• 专利附录
  • 专利说明
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    • 专利摘要:
    The invention relates to a composition containing a first semiconductor SC1, particles comprising one or more element (s) M in the metallic state chosen from an element of groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the periodic table of elements, and a second semiconductor SC2 comprising cerium oxide, said first semiconductor SC1 being in direct contact with said particles comprising one or more element (s) M to the metallic state, said particles being in direct contact with said second semiconductor SC2 comprising cerium oxide so that the second semiconductor SC2 covers at least 50% of the surface of the particles comprising one or more elements (s) M in the metallic state. The invention also relates to its preparation process as well as its application in photocatalysis
    公开号:FR3026964A1
    申请号:FR1459846
    申请日:2014-10-14
    公开日:2016-04-15
    发明作者:Dina Lofficial；Antoine Fecant；Denis Uzio；Eric Puzenat；Christophe Geantet
    申请人:IFP Energies Nouvelles IFPEN；
    IPC主号:
    专利说明:

    [0001] The field of the invention is that of composite materials and their application in photocatalysis. By composite material is meant a solid consisting of at least two compounds of different chemical natures.
    [0002] In the following, the groups of chemical elements are given according to the classification CAS (CRC Handbook of Chemistry and Physics, publisher CRC press, editor-in-chief D. R. Lide, 81 st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals of columns 8, 9 and 10 according to the new IUPAC classification.
    [0003] PRIOR ART Examples of composite materials containing semiconductors, in particular composite materials composed of core-layer particles on the surface of a semiconductor substrate, exist in the literature. This type of solid has particularly been developed in photocatalytic applications. C. Li et al (J. Hydrogen Energy, 37, pp. 6431-6437, 2012) have unveiled the synthesis of TiO 2 nanotube-based solids on which are deposited in a photo-assisted manner oxidized metallic copper particles in their entirety. area. H. Lin et al. (Cat., 21: 91-95, 2012) propose a composite prepared by coprecipitation composed of AgBr / Ag / Agl, AgBr and Agl both being semiconductors. C. Wang et al. (Chem Eng J., 237, p.29-37, 2014) prepared by successive impregnations a material having contacts between WO3 and Pt on the one hand and Pt and TiO2 on the other hand prepared by coprecipitation. Finally, H. Tada (Nature Materials, 5, pp. 782-786, 2006) proposes a solid based on hemispherical particles having a layer of CdS around an Au core, which particles are deposited on the semiconductor surface. TiO2 conductor. The object of the invention is to provide a composition containing a first semiconductor SC1, particles comprising one or more element (s) M in the metallic state chosen from a group element IVB, VB, VIB, VIIB , VIIIB, IB, IIB, IIIA, IVA and VA of the periodic table of the elements, and a second semiconductor SC2 comprising cerium oxide, said first semiconductor SC1 being in direct contact with said particles having one or 3026964 2 a plurality of metallic element M, said particles being in direct contact with said second semiconductor SC2 comprising cerium oxide so that the second semiconductor SC2 covers at least 50% of the surface; particles having one or more element (s) M in the metallic state. The use of cerium oxide constituting the semiconductor SC2 makes it possible, surprisingly, to obtain a photocatalyst having improved photocatalytic performance compared with photocatalysts known from the state of the art. According to a preferred variant, the first semiconductor SC1 is furthermore in direct contact with the second semiconductor SC2. According to a preferred variant, said first semiconductor SC1 forms a support, said support contains at its surface core-layer type particles, said layer being formed by said semiconductor SC2 comprising cerium oxide, said core being formed by said particles having one or more element (s) M in the metallic state. According to one variant, the cerium oxide is mainly composed of Ce 2 O 3. According to one variant, the element M in the metallic state is chosen from platinum, palladium, gold, nickel, cobalt, ruthenium, silver, copper, rhenium or rhodium.
    [0004] According to one variant, the content of cerium oxide, expressed as element Ce, is between 0.01 and 50% by weight relative to the total weight of the composition. According to one variant, the content of element (s) M in the metallic state is between 0.001 and 20% by weight relative to the total weight of the composition.
    [0005] According to a variant, said particles comprising one or more element (s) M in the metallic state are in the form of particles of sizes between 0.5 nm and 1000 nm. According to one variant, the composition is in the form of a nanometric powder.
    [0006] According to one variant, the semiconductor SC1 is selected from TiO2, Bi2S3, Bi2O3, Fe2O3, ZnO, WO3, CuO, ZnFe2O4, MoS2, and In (OH) 3. According to one variant, the layer has a thickness of 1 nm to 1000 nm.
    [0007] The invention also relates to a process for preparing it comprising the following steps: a) a suspension containing a first semiconductor SC1 is prepared under agitation in a liquid mixture composed of water and / or one or more organic compounds and at least one metal precursor selected from an element of Groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the Periodic Table of Elements, and the suspension is irradiated by an irradiation source such that at least a part of the emission spectrum of said source is composed of photons with energies greater than the bandgap width of the semiconductor SC1; b) said irradiation source is introduced under agitation and under irradiation; cerium precursor at the degree of oxidation +3 soluble in the suspension obtained in step a), c) is then introduced with stirring and under irradiation of said irradiation source a basic agent or acid of in order to cause the precipitation of the cerium oxide, d) then the composition is separated from the suspension of step c), e) the composition obtained in step d) is dried, f) optionally, the dried composition obtained in step e) at a heat treatment. According to one variant, the metal precursor is chosen from a precursor of platinum, palladium, gold, nickel, cobalt, ruthenium, silver, copper, rhenium or rhodium.
    [0008] Alternatively, in step c) the pH is between 9 and 13 after the introduction of the basic or acidic agent. The invention also relates to the use of the composition according to the invention or prepared according to the preparation method as photocatalyst.
    [0009] DETAILED DESCRIPTION OF THE INVENTION Composition according to the invention The invention relates to a composition containing a first semiconductor SC1, particles comprising one or more element (s) M in the metallic state 3026964 4 selected from an element of the groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the periodic table of elements, and a second semiconductor SC2 comprising cerium oxide, said first semiconductor SC1 being in contact directly with said particles comprising one or more element (s) M in the metallic state, said particles being in direct contact with said second semiconductor SC2 comprising cerium oxide so that the second semiconductor SC2 covers at least 50% of the surface of the particles comprising one or more element (s) M in the metallic state. Preferably, the composition consists of a first semiconductor SC1, particles comprising one or more element (s) M in the metallic state chosen from an element of groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the periodic table of elements, and a second semiconductor SC2 comprising cerium oxide.
    [0010] According to an important aspect of the invention, the first semiconductor SC1 is in direct contact with particles comprising one or more element (s) M in the metallic state, said particles being in direct contact with a second semiconductor SC2 comprising cerium oxide. Preferably, the first semiconductor SC1 is further in direct contact with the second semiconductor SC2. According to a preferred variant of the invention, said first semiconductor SC1 forms a support, said support contains on its surface core-layer type particles, said layer being formed by said semiconductor SC2 comprising cerium, said core being formed by said particles comprising one or more element (s) M in the metallic state. The use of cerium oxide constituting the layer of the core-layer-type particles at the surface of a semiconductor support SC1 according to the invention makes it possible, surprisingly, to obtain a photocatalyst having improved photocatalytic performance compared with photocatalysts. known from the state of the art not containing the supported core-layer architecture. The second semiconductor SC2 covers at least 50% of the surface of the particles comprising one or more element (s) M in the metallic state, a surface area of preferably greater than 60% and very preferably greater than 75%. %. The layer has a thickness of 1 nm to 1000 nm, preferably 1 nm to 500 nm, and particularly preferably 2 to 50 nm.
    [0011] The composition contains a first SC1 semiconductor. SC1 semiconductors used according to the invention comprise at least one inorganic, organic or organic-inorganic composite semiconductor. The bandgap width of the inorganic, organic or organic-inorganic semiconductor is generally between 0.1 and 5.5 eV.
    [0012] According to a first variant, the semiconductor SC1 comprises at least one inorganic solid. The inorganic semiconductor may comprise one or more of the elements selected from Group IVA elements, such as silicon, germanium, silicon carbide or silicon-germanium. It may also be composed of elements of groups IIIA and VA, such as GaP, GaN, InP and InGaAs, or elements of groups IIB and VIA, such as CdS, ZnO and ZnS, or elements of groups IB and VIIA, such as CuCl and AgBr, or elements of groups IVA and VIA, such as PbS, PbO, SnS and PbSnTe, or elements of groups VA and VIA, such as Bi2Te3 and Bi203, or elements of groups IIB and VA, such as Cd3P2, Zn3P2 and Zn3As2, or elements of groups IB and VIA, such as CuO, Cu2O and Ag2S, or of elements of groups VIII and VIA, such as CoO, PdO, Fe2O3 and NiO, or elements of groups VIB and VIA, such as MoS2 and WO3, or elements of groups VB and VIA, such as V205 and Nb2O5, or elements of groups IVB and VIA, such as TiO2 and HfS2, or elements of groups IIIA and VIA, such as In203, In253 or In (OH) 3, or elements of groups VIA and lanthanides, such as Ce203, Pr203, Sm253, Tb2S3 and La2S3, or elements VIA groups and actin ides, such as UO2 and UO3. Preferably, the semiconductor is selected from TiO2, Bi2S3, Bi203, CdO, Ce203, CeO2, CoO, Cu2O, Fe2O3, FeTiO3, In203, In (OH) 3, NiO, PbO, ZnO, WO3, CuO, ZnFe2O4, MoS2, Ag2S, CdS, Ce2S3, Cu2S, CuInS2, In2S3, ZnFe2O3, ZnS and ZrS2 and In (OH) 3. Most preferably, the semiconductor is selected from TiO2, Bi2S3, Bi2O3, Fe2O3, ZnO, WO3, CuO, ZnFe2O4, MoS2, and In (OH) 3. According to another variant, the semiconductor SC1 comprises at least one organic semiconductor. Organic semiconductors include tetracene, anthracene, polythiophene, polystyrenesulfonate, phosphyrenes and fullerenes. According to another variant, the semiconductor SC1 comprises at least one organic-inorganic semiconductor. Among the organic-inorganic semiconductors, mention may be made of crystalline solids of the MOF type (for Metal Organic Frameworks according to the English terminology). The MOFs consist of inorganic subunits (transition metals, lanthanides, etc.) connected to each other by organic ligands (carboxylates, phosphonates, imidazolates, etc.), thus defining crystallized hybrid networks, sometimes porous.
    [0013] The semiconductor SC1 may optionally be doped with one or more ions selected from metal ions, such as, for example, ions of V, Ni, Cr, Mo, Fe, Sn, Mn, Co, Re, Nb, Sb, La, Ce, Ta, Ti, non-metallic ions, such as for example C, N, S, F, P, or a mixture of metal and non-metallic ions. According to another variant, the semiconductor SC1 may be surface-sensitized with any organic molecules capable of absorbing photons. The semiconductor SC1 may be in different forms (nanometric powder, nanoobjects with or without cavities, ...) or shaped (films, monolith, beads of micrometric or millimeter size, ...).
    [0014] The composition contains a second SC2 semiconductor. The semiconductor SC2 comprises cerium oxide. Preferably, the cerium element is at oxidation levels +3 and / or +4. Very preferably, the cerium oxide is mainly composed of Ce 2 O 3. The term "mainly composed of Ce 2 O 3" means a Ce 2 O 3 content greater than 50% by weight, preferably greater than 60% by weight and particularly preferably greater than 70% by weight of the total weight of the SC2 semiconductor. Optionally, the semiconductor SC2 may further contain cerium hydroxides. The semiconductor SC2 preferably contains no other element of the group of metals than cerium. The cerium oxide content, expressed as Ce element, is between 0.01 and 50% by weight, preferably between 0.5 and 20% by weight relative to the total weight of the composition.
    [0015] The composition comprises particles comprising one or more element (s) M in the metallic state chosen from an element of Groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the Periodic Table. elements. Said particles comprising one or more element (s) M are in direct contact with said semiconductor SC1 and SC2 respectively. Said particles can be composed of a single element in the metallic state or of several elements in the metallic state that can form an alloy. The term "element in the metallic state" means an element belonging to the family of metals, said element being at the zero oxidation state (and thus in the form of metal). Preferably, the element or elements M in the metallic state are chosen from a metal element of groups VIIB, VIIIB, IB and IIB of the periodic table of elements, and particularly preferably from platinum, palladium, gold, nickel, cobalt, ruthenium, silver, copper, rhenium or rhodium.
    [0016] Said particles comprising one or more element (s) M in the metallic state are preferably in the form of particles of sizes between 0.5 nm and 1000 nm, very preferably between 0.5 nm and 100 nm. The content of element (s) M in the metallic state is between 0.001 and 20% by weight, preferably between 0.01 and 10% by weight relative to the total weight of the composition. The composition according to the invention can be in various forms (nanometric powder, nanoobjects with or without cavities, ...) or shaped (films, monolith, beads of micrometric or millimeter size, ...). The composition according to the invention is advantageously in the form of a nanometric powder. Preparation of the solid The composition according to the invention may be prepared according to any method known to those skilled in the art. According to one embodiment, the composition is obtained by photodeposition of the metal element (s) M forming the metal particles (and thus the core in a supported core-layer architecture), then by condensation induced by precipitation under irradiation of a cerium precursor. of +3 oxidation state (forming the layer in a supported core-layer architecture) on a semiconductor SC1 (forming the support in a supported core-layer architecture) containing the metal particles on its surface. It should be noted that a preparation by the dry impregnation technique (generally seeking a high dispersion of the metal on the support) of a copper precursor does not make it possible to obtain a composition according to the invention in which the second semiconductor SC2 comprising copper oxide covers at least 50% of the surface of the particles comprising one or more element (s) M in the metallic state.
    [0017] More particularly, the process for preparing the composition according to the invention comprises the following steps: a) a suspension containing a first semiconductor SC1 is prepared with stirring in a liquid mixture composed of water and / or one or more compounds and at least one metal precursor selected from an element of Groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the Periodic Table of Elements, and the suspension is irradiated by a source of irradiation such that at least a portion of the emission spectrum of said source is composed of photons of energies greater than the forbidden band width of the semiconductor SC1, b) is introduced with stirring and under irradiation of said source of irradiation a cerium precursor at the degree of oxidation +3 soluble in the suspension obtained in step a), c) is then introduced with stirring and irradiation of said irradiation source a basic agent or acid to cause precipitation of the cerium oxide, d) then the composition is separated from the suspension of step c), e) the composition obtained in step d) is dried, f) optionally, the dried composition obtained in step e) is subjected to a heat treatment.
    [0018] Thus, in step a), a suspension containing a SC1 semiconductor, preferably in the form of a nanometric powder, is prepared with stirring in a liquid mixture composed of water and / or one or more organic compounds and at least one metal precursor selected from an element of Groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the Periodic Table of Elements, and the suspension is irradiated by an irradiation source such that at least a portion of the emission spectrum of said source is composed of photons of energies greater than the forbidden bandgap of the semiconductor SC1.
    [0019] The percentage of organic compounds contained in the suspension varies from 0 to 100% by volume. The organic compounds are generally primary or secondary alcohols, preferably the organic compounds are methanol, ethanol or isopropanol, alone or as a mixture. The metal precursor is introduced into the mixture in the form of a soluble powder or in solution, preferably in aqueous solution. The metal precursor is generally based on acetate, acetylacetonate, chloride, nitrate or sulfate. Preferably, the metal precursor is based on chloride or nitrate. The metal precursor is chosen from an element of Groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the Periodic Table of Elements, preferably from Groups VIIB, VIIIB, IB and IIB. of the periodic table of elements. Very preferably, the precursor is a precursor of platinum, palladium, gold, nickel, cobalt, ruthenium, silver, copper, rhenium or rhodium.
    [0020] The amounts of the metal precursor introduced into the suspension are chosen such that the content of element (s) M in the metallic state is between 0.001 and 20% by weight, preferably between 0.01 and 10%. by weight relative to the total weight of the composition. The semiconductor SC1 introduced in step a) is one of the previously described semiconductors. The mixture is preferably carried out at ambient temperature with stirring, preferably mechanically or by bubbling. The mixture is irradiated by a source such that at least a portion of the emission spectrum is composed of photons of energies greater than the forbidden bandwidth of the semiconductor employed. Preferably, the source emits at least a wavelength range greater than 280 nm, very preferably 315 nm to 800 nm, which includes the UV spectrum and / or the visible spectrum. The radiation source may be any source of artificial or natural electromagnetic radiation, such as natural sunlight, a Hg type lamp, a Xe type lamp, an LED type lamp. The duration of this step is preferably between 1 minute and 20 hours under irradiation, preferably between 1 minute and 5 hours.
    [0021] During step a), the M5 + metal ions of the precursor are reduced in the form of metal particles M ° at the surface of the semiconductor SC1 under the action of the electrons generated by the absorption of photons by said semiconductor. When the composition is in the form of a supported core-layer architecture, these metal particles form the core of the composition according to the invention. In step b), a cerium precursor with a degree of oxidation +3 soluble in the suspension obtained in step a) is introduced with stirring and under irradiation of the said irradiation source.
    [0022] The cerium precursor is generally based on chloride, sulfate, acetate, bromide, fluoride, acetylacetonate, nitrate, hydroxide, carbonate. Preferably, the precursor is cerium chloride or nitrate. The cerium precursor may be solubilized prior to introduction into water or a liquid mixture composed of water and one or more organic compounds such as primary or secondary alcohols, and preferably, methanol, methanol, and the like. ethanol or isopropanol, alone or in admixture. Optionally, and in order to ascertain the solubility of the cerium precursor, an acidic agent may be added to the mixture to modulate the pH of the solution. The acidic agent is preferably selected from inorganic acids such as nitric, sulfuric, phosphoric, hydrochloric, hydrobromic acid or organic acids such as carboxylic or sulfonic acids. The pH of the solution is less than 7, preferably less than 5. The amounts of the cerium precursor introduced into the suspension are chosen such that the cerium oxide content, expressed as Ce element, is between 0, 01 and 50% by weight, preferably between 0.5 and 20% by weight relative to the total weight of the composition. The agitation and irradiation conditions are those described for step a). The agitation and irradiation conditions are preferably identical to those of step a). The duration of this step is preferably between 1 minute and 20 hours, preferably between 1 minute and 5 hours. In step c), a basic or acidic agent is introduced with stirring and under irradiation of the said irradiation source so as to cause the precipitation of the cerium oxide, in particular of Ce 2 O 3. Preferably, the pH is modified by the addition of a basic or acidic agent in such a manner that it is in a range between 9 and 13 after the addition of the agent. When a basic agent is introduced, it is preferably selected from alkali or alkaline earth hydroxides, organic bases such as amines or ammonia. When an acidic agent is introduced, it is preferably selected from inorganic acids such as nitric, sulfuric, phosphoric, hydrochloric, hydrobromic acid or organic acids such as carboxylic or sulfonic acids.
    [0023] The stirring and irradiation conditions of step c) are those described for step a). The agitation and irradiation conditions are preferably identical to those of step a). The duration of this step is preferably between 1 minute and 20 hours, preferably between 1 minute and 5 hours. During step c), the metal ions Ce3 + precipitate in the form of a metal oxide layer Ce203 on the surface of the metal particles M deposited in step a), under the action of the basic agent or introduced acid. . The M / Semiconductor SC1 interface promotes the localization of the photogenerated electrons by the absorption of photon in said semiconductor SC1 at the surface of the metal particles M and thus induces a negative surface charge of said metal particles M, hence the preferential localization of the Ce203 oxide layer on the metal particles due to the electrostatic attraction between Ce3 + and M (5-). In step d), the composition is separated from the suspension of step c). The separation can be carried out by filtration or by centrifugation. Preferably it is carried out by centrifugation. Generally, this centrifugation is carried out for 10 to 60 minutes from 2000 to 10,000 revolutions per minute. Preferably, one to three washes with water are then carried out.
    [0024] In step e), the composition obtained in step d) is dried. Drying is carried out at 30 ° C to 200 ° C, usually for 1 to 48 hours, preferably in air. Optionally, this drying can be carried out under an inert atmosphere. Drying may optionally be carried out in an oven or rotary evaporator.
    [0025] The drying step can optionally be carried out under partial vacuum. According to one embodiment, a separation step can be carried out between steps a) and b), preferably by centrifugation, an optional washing step, and a drying step under the conditions described above.
    [0026] Optionally, the dried composition obtained in step e) is subjected to a heat treatment (step f). The heat treatment is carried out under air flow, nitrogen, hydrogen or partial vacuum, generally at a temperature between 50 ° C and 500 ° C, preferably for a period between 1 and 16 hours.
    [0027] The invention also relates to the use of the composition according to the invention as a photocatalyst, and in particular as a photocatalyst for the degradation of organic compounds, such as, for example, formic acid. The photocatalytic process for the degradation of organic compounds, such as, for example, the photocatalytic degradation of formic acid, is carried out by bringing into contact a stream containing an organic compound with said composition according to the invention. The composition is then irradiated with at least one irradiation source producing at least one wavelength suitable for activating said composition so as to degrade the organic compound, for example formic acid with hydrogen and with CO2. The composition can be used in a photocatalytic process in a liquid or gaseous medium. The implementation of the photocatalytic process can be done in fixed bed crossed, in fixed bed licking or in suspension (also called "slurry" according to the English terminology). It can also be done in reactors entirely made of glass or having non-absorbing optical windows in order to allow the radiation to reach the surface of the solid. The type of reactor technology for the implementation of the solid is generally adapted to a suspension. This type of technology is also called "slurry" according to the terminology 3026964 13 Anglo-Saxon. The type of reactor technology may be of the solar panel type with licking bed or through porous or non-porous support. The photocatalyst can also be deposited directly on optical fibers. Any irradiation source emitting at least one wavelength suitable for activating said composition, that is to say absorbable by the composition, may be used according to the invention. The irradiation of the source is therefore such that at least a portion of the emission spectrum of said source is composed of photons of energies greater than the forbidden band width of the composition according to the invention. Preferably, the source emits at least one wavelength range greater than 280 nm, most preferably 315 nm to 800 nm, which includes the UV spectrum and / or the visible spectrum. The source of radiation may be any source of artificial or natural electromagnetic radiation, such as natural sunlight, a type of lamp Hg, a lamp type Xe, a lamp type LED. The use of the composition is conditioned by the provision of photons 15 adapted to the photocatalytic system for the reaction envisaged and therefore is not limited to a specific pressure or temperature range apart from those for providing stability. of the product (s). The temperature range employed for use of the composition is generally from -10 ° C to + 200 ° C, preferably from 0 to 150 ° C, and most preferably from 0 to 50 ° C. The pressure range used for the use of the composition is generally from 0.01 MPa to 70 MPa (0.1 to 700 bar), more preferably from 0.1 MPa to 2 MPa (1 to 20 bar). The invention is illustrated by the following examples, which in no way present a limiting character.
    [0028] EXAMPLES Example 1: Solid A according to the invention Ce 2 O 3 / Pt / TiO 2 0.0712 g of H 2 PtCl 6 6H 2 O (37.5% by weight of metal) is inserted in 500 ml of distilled water. 50 ml of this solution are taken and inserted into a double-jacketed glass reactor. 3 ml of methanol then 250 mg of TiO2 (P25, DegussaTM) are then added with stirring to form a suspension.
    [0029] The mixture is then left stirring and under UV radiation for two hours. The lamp used to provide UV radiation is a 125W Mercury vapor HPKTM lamp. The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washings with water are then carried out, each washing being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours. The solid A 'Pt / TiO 2 is then obtained. The Pt element content is measured by plasma atomic emission spectroscopy (ICP-AES) at 0.93% by mass. A solution of Ce (NO3) 3 is prepared by dissolving 0.05 g of Ce (NO3) 3, 6H2O (Sigma-AldrichTM, 99%) in 50 ml of H 2 O, a concentration of Ce3 + of 2.3 mmol. / L. In the reactor were introduced: 0.10 g of solid A ', 25 ml of distilled water and finally 25 ml of isopropanol. The system is purged in the dark under a stream of argon (100 ml / min) for 2 hours. The reactor is thermostated at 25 ° C. throughout the synthesis.
    [0030] The argon flow is then slowed down to 30 ml / min and the irradiation of the reaction mixture starts. The lamp used to provide the UV radiation is a mercury vapor HPKTM lamp 125 W. Then, 5 ml of the cerium nitrate solution is added to the mixture. The mixture is left for 1 hour with stirring and irradiation. 1 ml of a 30% solution of NH3 is then added. The mixture is again left for 1 hour with stirring and irradiation. The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washings with water are then carried out, each washing being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours.
    [0031] The solid A Ce 2 O 3 / Pt / TiO 2 is then obtained. The content of element Ce is measured by ICP-AES at 1.7% by weight. By XPS measurement (X-Ray Photoelectron Spectrometry according to the English terminology), a recovery of platinum particles greater than 83% and cerium oxide phases are measured at 74% Ce203 and 26% CeO2. By transmission electron microscopy, an average layer thickness of 4 nm cerium oxide was measured around the metal particles. Example 2: B solid according to the invention Ce 2 O 3 / Pt / TiO 2 0.0710 g of H 2 PtCl 6 H 2 O (37.5% by weight of metal) is inserted into 500 ml of distilled water. 50 ml of this solution are taken and inserted into a double jacketed glass reactor. 3 ml of methanol then 250 mg of TiO2 (P25, DegussaTM) are then added with stirring to form a suspension. The mixture is then left stirring and under UV radiation for two hours. The lamp used to provide the UV radiation is a 125W mercury vapor lamp HPKTM 10. The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washings with water are then carried out, each washing being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours.
    [0032] The solid B 'Pt / TiO 2 is then obtained. The content of Pt element is measured by ICP-AES at 0.92% by mass. A solution of Ce (NO3) 3 is prepared by dissolving 0.05 g of Ce (NO3) 3, 6H2O (Sigma-AldrichTM, 99%) in 50 ml of H 2 O, a concentration of Ce3 + of 2.3 mmol / L.
    [0033] In the reactor were introduced: 0.10 g of solid B ', 25 ml of distilled water and finally 25 ml of isopropanol. The system is purged in the dark under a stream of argon (100 ml / min) for 2 hours. The reactor is thermostated at 25 ° C. throughout the synthesis. The argon flow is then slowed down to 30 ml / min and the irradiation of the reaction mixture starts. The lamp used to provide the UV radiation is a 125 W mercury vapor HPKTM lamp. Then, 10 ml of the cerium nitrate solution is added to the mixture. The mixture is left for 1 hour with stirring and irradiation. 1 ml of a 30% solution of NH3 is then added. The mixture is again left for 1 hour with stirring and irradiation.
    [0034] The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washes with water are then carried out, each of the washes being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours. The solid B Ce 2 O 3 / Pt / TiO 2 is then obtained. The content of element Ce is measured by ICP-AES at 3.8% by weight. By XPS measurement, a platinum particle coverage greater than 90% and cerium oxide phases were measured at 77% Ce 2 O 3 and 23% CeO 2. Transmission electron microscopy measured an average layer thickness of cerium oxide of 11 nm around the metal particles. Example 3: Solid C according to the invention Ce 2 O 3 / Pt / ZnO 0.0710 g of H 2 PtCl 6 6H 2 O (37.5% by weight of metal) is inserted into 500 ml of distilled water. 50 ml of this solution are taken and inserted into a double jacketed glass reactor. 3 ml of methanol then 250 mg of ZnO (Lotus SynthesisTM, specific surface area 50 m 2 / g) are then added with stirring to form a suspension.
    [0035] The mixture is then left stirring and under UV radiation for two hours. The lamp used to provide UV radiation is a 125W Mercury vapor HPKTM lamp. The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washes with water are then carried out, each of the washes being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours. The solid C 'Pt / ZnO is then obtained. The content of Pt element is measured by ICP-AES at 0.80% by weight. A solution of Ce (NO3) 3 is prepared by dissolving 0.05 g of Ce (NO3) 3, 6H2O (Sigma-AldrichTM, 99%) in 50 ml of H 2 O, a concentration of Ce3 + of 2.3 mmol. / L. In the reactor were introduced: 0.10 g of the solid C ', 25 ml of distilled water and finally 25 ml of isopropanol. The system is purged in the dark under a stream of argon (100 ml / min) for 2 hours. The reactor is thermostated at 25 ° C throughout the synthesis. The argon flow is then slowed down to 30 ml / min and the irradiation of the reaction mixture starts. The lamp used to provide the UV radiation is a 125 W mercury vapor lamp HPKTM. Then, 10 ml of the cerium nitrate solution is added to the mixture. The mixture is left for 1 hour with stirring and irradiation. 1 ml of a 30% solution of NH3 is then added. The mixture is again left for 1 hour with stirring and irradiation.
    [0036] The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washings with water are then carried out, each washing being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours. The solid C Ce203 / Pt / ZnO is then obtained. The content of element Ce is measured by ICP-AES at 3.7% by mass. By XPS measurement, a recovery of platinum particles greater than 89% and cerium oxide phases 81% Ce203 and 19% CeO2. Transmission electron microscopy measured an average layer thickness of cerium oxide of 12 nm around the metal particles.
    [0037] Example 4: D solid according to the invention Ce 2 O 3 / Au / TiO 2 0.0472 g of HAuCl 4, xH 2 O (52% by weight of metal, AldrichTM) is inserted into 500 ml of distilled water. 50 ml of this solution are taken and inserted into a double jacketed glass reactor. 3 mL of methanol and then 250 mg of TiO2 (P25, DegussaTM) are then added with stirring to form a suspension. The mixture is then left stirring and under UV radiation for two hours. The lamp used to provide UV radiation is a 125W Mercury vapor HPKTM lamp. The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washings with water are then carried out, each washing being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours. An Au / TiO 2 solid is then obtained. The Au element content is measured by ICP-AES at 0.95% by mass.
    [0038] A solution of Ce (NO3) 3 is prepared by dissolving 0.05 g of Ce (NO3) 3, 6H2O (Sigma-AldrichTM, 99%) in 50 ml of H 2 O, a concentration of Ce3 + of 2.3 mmol. / L.
    [0039] In the reactor were introduced: 0.10 g of the solid D ', 25 ml of distilled water and finally 25 ml of isopropanol. The system is purged in the dark under a stream of argon (100 ml / min) for 2 hours. The reactor is thermostated at 25 ° C. throughout the synthesis.
    [0040] The argon flow is then slowed down to 30 ml / min and the irradiation of the reaction mixture starts. The lamp used to provide the UV radiation is a 125 W mercury vapor HPKTM lamp. Then, 10 ml of the cerium nitrate solution is added to the mixture. The mixture is left for 1 hour with stirring and irradiation. 1 ml of a 30% solution of NH3 is then added. The mixture is again left for 1 hour with stirring and irradiation. The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washings with water are then carried out, each washing being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours.
    [0041] The solid D Ce 2 O 3 / Au / TiO 2 is then obtained. The content of element Ce is measured by ICP-AES at 3.6% by weight. By XPS measurement, a coverage of gold particles greater than 90% and cerium oxide phases at 75% Ce 2 O 3 and 25% CeO 2 are measured. Transmission electron microscopy measured an average layer thickness of cerium oxide of 14 nm around the metal particles. Example 5: Solid E, not in accordance with the invention Ce 2 O 3 / Pt / TiO 2 0.0710 g of H 2 PtCl 6 6H 2 O (37.5% by weight of metal, AldrichTM) is inserted into 500 ml of distilled water. 50 ml of this solution are taken and inserted into a double jacketed glass reactor. 3 ml of methanol then 250 mg of TiO2 (P25, DegussaTM) are then added with stirring to form a suspension. The mixture is then left stirring and under UV radiation for two hours. The lamp used to provide the UV radiation is a mercury vapor HPKTM lamp of 125 W. The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washings with water are then carried out, each washing being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours.
    [0042] A solid E 'Pt / TiO 2 is then obtained. The content of Pt element is measured by ICP-AES at 0.94% by mass. A solution of Ce (NO3) 3 is prepared by dissolving 0.05 g of Ce (NO3) 3, 6H2O (Sigma-AldrichTM, 99%) in 50 ml of H 2 O, a concentration of Ce3 + of 2.3 mmol. / L. In the reactor were introduced: 0.10 g of the solid E ', 25 ml of distilled water and finally 25 ml of isopropanol. The system is purged in the dark under a stream of argon (100 ml / min) for 2 hours. The reactor is thermostated at 25 ° C. throughout the synthesis.
    [0043] The argon flow is then slowed down to 30 ml / min. Then 10 ml of the cerium nitrate solution is added to the mixture. The mixture is left stirring for 1 hour and without irradiation. 1 ml of a 30% solution of NH3 is then added. The mixture is again left for 1 hour with stirring and without irradiation. The mixture is then centrifuged for 10 minutes at 3000 rpm to recover the solid. Two washings with water are then carried out, each washing being followed by centrifugation. The recovered powder is finally placed in an oven at 70 ° C. for 24 hours. The solid E Ce203 / Pt / TiO2 is then obtained. The content of element Ce is measured by ICP-AES at 3.8% by weight. By XPS measurement, a platinum particle coverage of about 21% and cerium oxide phases were measured at 76% Ce 2 O 3 and 24% CeO 2. By transmission electron microscopy, a layer of cerium oxide is sometimes distinguished around the metal particles without being able to measure an average thickness because of the inhomogeneity of the distribution.
    [0044] Example 6: Solid F (not in accordance with the invention) TiO2 Solid F is commercial titanium dioxide TiO2 P25, DegussaTM Example 7: Evaluation of Photocatalytic Degradation Solids of Formic Acid Solids A, B, C, D , E and F are subjected to a photocatalytic test for the production of dihydrogen by formic acid degradation in a pyrex stirred semi-open reactor equipped with a quartz optical window and a jacket to regulate the test temperature. . 100 mg of solids are suspended in 60 ml of a 0.5 mol / l aqueous formic acid solution. The tests are carried out at 25 ° C. under atmospheric pressure with an argon flow rate of 5 ml / min to entrain the hydrogen gas product which is analyzed by gas chromatography. The UV-Visible irradiation source is provided by an Xe-Hg lamp (Asahi ™, MAX302 ™). The irradiation power is always maintained at 100%. The duration of the test is 20 hours. Photocatalytic activities are expressed in moles of dihydrogen produced per hour and per gram of photocatalyst. The results are reported in Table 1. The activity values show that the solids according to the invention systematically have the best photocatalytic performance. Photocatalyst Initial SC2 / M / SC1 activity (ilmol / h / g) Solid A (compliant) Ce203 / Pt / TiO2 1027 Solid B (compliant) Ce203 / PtiTiO2 1232 Solid C (compliant) Ce203 / Pt / ZnO 793 Solid D (compliant) Ce203 / Au / TiO2 912 Solid E (non-compliant) Ce203 / Pt / TiO2 234 Solid F (non-compliant) TiO2 12 Table 1: Initial activity solids performances for the production of dihydrogen by formic acid degradation
    权利要求:
    Claims (15)
    [0001]
    REVENDICATIONS1. Composition containing a first semiconductor SC1, particles comprising one or more element (s) M in the metallic state chosen from an element of groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the periodic table of elements, and a second semiconductor SC2 comprising cerium oxide, said first semiconductor SC1 being in direct contact with said particles comprising one or more element (s) M in the metallic state, said particles being in direct contact with said second semiconductor SC2 comprising cerium oxide so that the second semiconductor SC2 covers at least 50% of the surface of the particles comprising one or more element (s) M to the metallic state.
    [0002]
    2) The composition of claim 1, wherein the first semiconductor SC1 is in direct contact with the second semiconductor SC2.
    [0003]
    3) Composition according to one of claims 1 or 2, wherein said first semiconductor SC1 forms a support, said support contains on its surface core-layer type particles, said layer being formed by said SC2 semiconductor comprising cerium oxide, said core being formed by said particles comprising one or more element (s) M in the metallic state.
    [0004]
    4) Composition according to one of claims 1 to 3, wherein the cerium oxide is predominantly composed of Ce203.
    [0005]
    5) Composition according to one of claims 1 to 4, wherein the element M in the metallic state is selected from platinum, palladium, gold, nickel, cobalt, ruthenium, silver, copper, rhenium or rhodium.
    [0006]
    6) Composition according to one of claims 1 to 5, wherein the cerium oxide content, expressed as element Ce, is between 0.01 and 50% by weight relative to the total weight of the composition.
    [0007]
    7) Composition according to one of claims 1 to 6, wherein the content of element (s) M in the metallic state is between 0.001 and 20% by weight relative to the total weight of the composition.
    [0008]
    8) Composition according to one of claims 1 to 7, wherein said particles comprising one or more element (s) M in the metallic state are in the form of particle size between 0.5 nm and 1000 nm. 3026964 22
    [0009]
    9) Composition according to one of claims 1 to 8, which is in the form of nanoscale powder.
    [0010]
    10) Composition according to one of claims 1 to 9, wherein the semiconductor SC1 is selected from TiO2, Bi2S3, Bi203, Fe2O3, ZnO, WO0, CuO, ZnFe2O4, MoS2, and the in (OH) 3.
    [0011]
    11) Composition according to one of claims 3 to 10, wherein the layer has a thickness of 1 nm to 1000 nm.
    [0012]
    12) Process for the preparation of the composition according to claims 1 to 11 comprising the following steps: a) a suspension containing a first SC1 semiconductor in a liquid mixture composed of water and / or a plurality of organic compounds and at least one metal precursor selected from an element of Groups IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of the Periodic Table of Elements, and the suspension is irradiated by a source. irradiation such that at least a portion of the emission spectrum of said source is composed of photons of energies greater than the forbidden band width of the semiconductor SC1, b) is introduced with stirring and under irradiation of said source irradiation a cerium precursor at the degree of oxidation +3 soluble in the suspension obtained in step a), c) is then introduced with stirring and irradiation of said irradiation source a basic agent o acid in order to cause the precipitation of the cerium oxide, d) then the composition is separated from the suspension of step c), e) the composition obtained in step d), f) is optionally dried the dried composition obtained in step e) is subjected to a heat treatment.
    [0013]
    13) A process according to claim 12, wherein the metal precursor is selected from platinum, palladium, gold, nickel, cobalt, ruthenium, silver, copper, rhenium or of rhodium.
    [0014]
    14) Preparation process according to one of claims 12 or 13, wherein in step c) the pH is between 9 and 13 after the introduction of the basic agent or acid. 3026964 23
    [0015]
    15) Use of the composition according to claims 1 to 11 or prepared according to the process according to claims 12 to 14 as a photocatalyst.
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    同族专利:
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    JP2017533816A|2017-11-16|
    FR3026964B1|2019-10-25|
    WO2016058861A1|2016-04-21|
    ES2716726T3|2019-06-14|
    EP3206787A1|2017-08-23|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20060210636A1|2002-12-09|2006-09-21|Ralph Nonninger|Nanoscale core/shell particles and the production thereof|
    FR2961011A1|2010-06-08|2011-12-09|Commissariat Energie Atomique|NANOCOMPOSITE MATERIAL AND ITS USE IN OPTOELECTRONICS|
    CN103599776A|2013-11-21|2014-02-26|福州大学|Pd/CeO2 visible light catalyst and preparation method and application thereof|FR3053898A1|2016-07-13|2018-01-19|IFP Energies Nouvelles|PROCESS FOR PREPARING AN IRRADIATION-ASSISTED COBALT COMPOSITION|
    CN108273510B|2018-01-18|2020-06-30|三明学院|Z-shaped visible light response composite photocatalyst and preparation method thereof|
    CN111774085B|2020-07-10|2021-12-03|复旦大学|Transition metal carbide/metal organic framework compound and super-assembly preparation method thereof|
    KR102321703B1|2020-08-13|2021-11-04|숙명여자대학교 산학협력단|Photocatalyst including cerium oxide nanoparticles having selectivity in photocatalystic characteristics and method for manufacturing the same|
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    优先权:
    申请号 | 申请日 | 专利标题
    FR1459846A|FR3026964B1|2014-10-14|2014-10-14|PHOTOCATALYTIC COMPOSITION COMPRISING METALLIC PARTICLES AND TWO SEMICONDUCTORS INCLUDING CERIUM OXIDE|
    FR1459846|2014-10-14|FR1459846A| FR3026964B1|2014-10-14|2014-10-14|PHOTOCATALYTIC COMPOSITION COMPRISING METALLIC PARTICLES AND TWO SEMICONDUCTORS INCLUDING CERIUM OXIDE|
    JP2017519277A| JP6703984B2|2014-10-14|2015-10-06|Photocatalytic composition containing two kinds of semiconductors including those composed of metal particles and cerium oxide|
    PCT/EP2015/072995| WO2016058861A1|2014-10-14|2015-10-06|Photocatalytic composition comprising metallic particles and two semiconductors, one of which is composed of cerium oxide|
    US15/518,967| US10682630B2|2014-10-14|2015-10-06|Photocatalytic composition comprising metallic particles and two semiconductors, one of which is composed of cerium oxide|
    EP15774637.1A| EP3206787B1|2014-10-14|2015-10-06|Photocatalytic composition comprising metallic particles and two semiconductors, one of which is composed of cerium oxide|
    ES15774637T| ES2716726T3|2014-10-14|2015-10-06|Photocatalytic composition comprising metallic particles and two semiconductors, one of which is composed of cerium oxide|
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