Photo-anode material, preparation method thereof and water electrolysis hydrogen production system comprising photo-anode material

Abstract

The invention discloses a photo-anode material for producing hydrogen by electrolyzing water and a preparation method of the photo-anode material. The photo-anode material comprises an oxide MOx and doping elements (isoelectronic chalcogenide element atoms S, Se and Te) in a VI main group, wherein the doping elements are distributed in the metal oxide MOx. The preparation method comprises the following steps: (A) forming a metal oxide MOx; (B) carrying out annealing treatment on the metal oxide MOx; and (C) alloying the annealed MOx with group VI elements (S, Se, Te) to form a multi-component alloy containing the equivalent group VI elements. According to the photo-anode material for hydrogen production through water electrolysis and the preparation method of the photo-anode material, the forbidden band width of a photo-anode can be effectively reduced, the utilization rate of visible light in the water electrolysis process is increased, and therefore the photocatalytic performance of the photo-anode is improved, and the photovoltaic hydrogen production efficiency is further improved.

Description

Technical Field

[0001] The present disclosure relates to a photoanode material, and in particular to a photoanode material for a photochemical cell, a method for preparing the photoanode material, and a photochemical cell comprising the photoanode material. Background Art

[0002] Developing and utilizing various new renewable energy sources and promoting the adjustment of energy structure have become the main issues at present. As one of the most promising new energy sources, hydrogen energy has many advantages, such as clean products (only water), wide applications (can be used for power generation, heating and as a fuel for transportation), and diversified forms (appearing in gaseous, liquid or solid metal hydrides, which can adapt to the different requirements of storage and transportation and various application environments), etc. However, as a secondary energy source, hydrogen energy, like electricity, needs to be produced and prepared.

[0003] Photoelectrochemical cells (PECs) are light-driven cells that produce hydrogen and oxygen by electrolysis of water or aqueous solutions. The principle of photoelectrochemical water splitting is based on a cell that converts light energy into electricity and contains two electrodes immersed in an aqueous electrolyte, at least one of which is made of a semiconductor that is exposed to light and is able to absorb light. This electricity generated by the conversion of light energy is used for water electrolysis. The performance of PECs in terms of solar energy conversion efficiency and the resulting hydrogen production depends largely on the electrochemical properties of the semiconductor photoelectrode used in the water splitting process.

[0004] Most inorganic semiconductors have the potential for efficient photoelectrochemical (PEC) hydrogen production due to their favorable band gaps. However, unacceptably high corrosion rates inhibit the practical application of these materials. Some more stable and corrosion-resistant inorganic broadband semiconductor materials, such as metal oxides, cannot fully utilize the sufficient solar spectrum due to their large band gaps, so the energy conversion efficiency is quite low.

[0005] Therefore, those skilled in the art are in urgent need of a photoanode material for producing hydrogen by electrolysis of water and a preparation method thereof to ensure that the basic requirements of photochemical cells can be better met. Summary of the invention

[0006] The present disclosure provides a semiconductor oxide alloy and a preparation method thereof, according to which the bandgap energy width can be reduced for use in photoelectrochemical cell applications. This is achieved by introducing at least two Group VI elements, such as sulfur, selenium or tellurium, into metal oxides such as TiO2 or WO3 to form an alloy. Photoelectrodes made from these new semiconductor alloy materials provide better conversion efficiency for water decomposition and can provide a longer working life for hydrogen production using PECs. The method can also be extended to any broadband semiconductor oxide, whose bandgap energy gap can be changed by introducing equivalent Group VI elements. The present invention is committed to solving the related problems of material development in potential components of high-efficiency photoelectrochemical cells (PECs), which are used for spontaneous solar water decomposition to produce hydrogen.

[0007] According to the present disclosure, a photoanode material for producing hydrogen by electrolysis of water is provided, comprising: an oxide MOx and at least two doping elements in the VI main group distributed in the metal oxide MOx.

[0008] According to another aspect of the present disclosure, there is provided a method for preparing a photoanode material for producing hydrogen by electrolysis of water, comprising:

[0009] Step (A): Formation of metal oxide MO x ;as well as

[0010] Step (C): alloying the annealed MOx with at least two Group VI elements to form a multi-element alloy containing equivalent Group VI elements.

[0011] According to yet another aspect of the present disclosure, a water electrolysis hydrogen production system comprising the above-mentioned photoanode material is provided.

[0012] The photoanode material disclosed herein can effectively improve the utilization rate of visible light in the water electrolysis process, thereby improving the photocatalytic performance of the photoanode, and further improving the efficiency of photovoltaic hydrogen production.

[0013] The photoanode according to the present disclosure can be multiply doped with a plurality of elements of the VI main group, which makes the band gap adjustment controllability of the photoanode higher than that of single-unit doping. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention, wherein the drawings are only used to illustrate some embodiments of the present invention, but not to limit all embodiments of the present invention thereto.

[0015] Figure 1 Show W(S x O 1-x )3Band diagram near the center of the Brillouin zone;

[0016] Figure 2 Show W(S x O 1-x )3 and WO3 related spectral characteristics of the interband transition;

[0017] Figure 3 The Ti(S) relative to the vacuum level is shown x O 1-x )2, and its energy position diagram relative to the redox potential of the hydrogen production half reaction and the oxygen production half reaction at different pH values;

[0018] Figure 4 is a graph showing the relationship between the current density and the semiconductor bandgap energy calculated according to the Shockley-Queisser theoretical model under the condition of AM1.5G solar spectrum irradiance, and the corresponding solar hydrogen production efficiency (STH), showing that pure metal oxides WO3 and TiO2 have only about 4% and 2% STH efficiencies, respectively; and

[0019] Figure 5 is a schematic diagram showing a photoelectrochemical cell system according to the present disclosure. DETAILED DESCRIPTION

[0020] The technical solution of the present disclosure is described in detail below with reference to the specific embodiments of the present disclosure. It should be noted that in the following description and in the claims, specific numerical values ​​are not intended to be exact numerical values, but include reasonable deviations.

[0021] Photoelectrochemical cells (PECs) are light-driven cells that produce hydrogen and oxygen by electrolysis of water or aqueous solutions. The principle of photoelectrochemical water splitting is based on a cell that converts light energy into electricity and contains two electrodes immersed in an aqueous electrolyte, at least one of which is made of a semiconductor that is exposed to light and is able to absorb light. This electricity generated by the conversion of light energy is used for water electrolysis. The performance of PECs in terms of solar energy conversion efficiency and the resulting hydrogen production depends largely on the electrochemical properties of the semiconductor photoelectrode used in the water splitting process.

[0022] According to the principle of photoelectrochemistry, a given semiconductor material can cause intrinsic ionization when absorbing photons with energy greater than the band gap, generating electrons in its conduction band and forming holes in its valence band:

[0023] 2hν → 2e - + 2h + (1)

[0024] where h is Planck's constant, ν is the photon frequency, and e - It is an electron, h +are holes. When the energy of the photon (hν) is equal to or greater than the band gap, a reaction may occur (1). To avoid recombination of these charge carriers, an electric field is required at the electrode / electrolyte interface. This can be achieved by changing the potential at the electrode / electrolyte interface. Photoinduced holes can cause water molecules to split into gaseous oxygen and hydrogen ions:

[0025] 2h + + H2O(liquid)→1 / 2 O2(gas)+2H + (2)

[0026] This process (2) occurs at the photoanode / electrolyte interface. Gaseous oxygen is evolved at the photoanode, and hydrogen ions migrate to the cathode via the internal circuit (aqueous electrolyte). At the same time, electrons generated by reaction (1) at the photoanode are transferred to the cathode via the external circuit, resulting in the reduction of hydrogen ions to gaseous hydrogen at the cathode:

[0027] 2H + +2e - → H2(gas) (3)

[0028] Therefore, the overall reaction of PEC can be expressed as follows:

[0029] 2hν + H2O(liquid)→1 / 2O2(gas)+H2(gas) (4)

[0030] When the energy of the photon absorbed by the photoanode is equal to or greater than the total reaction threshold energy Et of the PEC, reaction (4) occurs:

[0031] Et = ΔG0(H2O) / 2N A , (5)

[0032] Where ΔG0(H2O) is the standard free enthalpy per mole of reaction (4), ΔG0(H2O) = 237.141 kJ / mol; where N A is Avogadro's number, N A =6.022×1023mol -1 . This produces:

[0033] Et = hν = 1.23 eV. (6)

[0034] According to equation (6), water can be electrochemically decomposed when the cell's electromotive force (EMF) is equal to or greater than 1.23 V. The oxygen production half reaction generally requires an additional overpotential (>0.275 V), while the hydrogen production half reaction requires an additional overpotential (>0.050 V) for both reactions to proceed at a reasonable rate. For a single photoelectrode cell, the acceptor (hole) electronic state or donor (electron) state of the cell must be located at the bulk Fermi level. Depending on the doping concentration of the bulk material, this bulk Fermi level is typically located 0.050-0.200 eV from the band edge. Considering all these factors that affect the working performance of PEC, the semiconductor and electrochemical properties of the photoelectrode must meet the following conditions:

[0035] 1. The conduction band and valence band edges must span H + / H2 and O2 / H2O redox potential;

[0036] 2. The optimal band gap is about 2.0eV;

[0037] 3. It must have superior corrosion resistance than other semiconductors with similar band gap.

[0038] According to the present disclosure, by using oxide MOx and doping the oxide with a Group VI element, a photoanode material satisfying the above three conditions is obtained, wherein preferably at least two Group VI elements are doped, and more preferably, one of the two doped Group VI elements is sulfur and the other is selected from Se or Te. The following is described with reference to the preferred embodiments of the present disclosure.

[0039] First embodiment

[0040] Titanium oxide (TiO2) or tungsten oxide (WO3) are semiconducting metal oxides used as photoanodes in conventional PEC cells for spontaneous water photolysis using sunlight. Figure 3 The curves showing the energy position of the redox potential of the hydrogen production half reaction and the oxygen production half reaction relative to the vacuum energy level as a function of the liquid pH value are shown in FIG. However, since the band gap width of TiO2 is 3.2 eV, such a large band gap energy makes it a material with very low solar energy conversion efficiency (theoretically only 3.4%), because it can only absorb the ultraviolet part, which accounts for about 4% of the total solar irradiance, and is not sensitive to the visible spectrum, such as Figure 4 WO3 has a similar situation.

[0041] According to the present disclosure, by doping TiO2 or WO3 with a doping element of Group VI, the bandgap of the formed photoanode material is reduced, for example, to around 2.0 eV, thereby obtaining a photoanode material with good performance.

[0042] According to the first embodiment, the photoanode material for producing hydrogen by electrolysis of water comprises WO3 or TiO2 and S and Se doping elements distributed in the metal oxide WO3 or TiO2, wherein the concentration of the S and Se doping elements is 1at% to 10at%. As a specific example, the concentration of the S doping element is 5at%, and the concentration of the Se doping element is 1at%.

[0043] like Figure 4 As shown in the figure and the subsequent Table 1, the band gap of the obtained photoanode material is about 2.1 eV, thereby improving the performance of the photoanode material.

[0044] The photoanode material according to this embodiment can be prepared, for example, by the following method, which includes the steps of:

[0045] Step (A): Deposit a WO3 or TiO2 film with a thickness of 200nm to 2000nm on a substrate using PVD ion beam sputtering (IBS); the substrate is glass or sapphire coated with SnO2, or stainless steel, this type of substrate material is used for thin film deposition; the source for making the WO3 or TiO2 film is a WO3 or TiO2 target. The substrate is placed in a deposition chamber with a nominal surface temperature of about 300K. Deposition is performed by sputtering the WO3 or TiO2 target using Ar plasma. The deposition rate is controlled by adjusting the RF power of the RF and monitored by the change in thickness.

[0046] Step (B): Post-deposition annealing is performed in a heating tube with a constant oxygen flow at a temperature of about 550° C. for a time of 0.5 h to 5.0 h.

[0047] Step (C): encapsulating a metal oxide WO3 or TiO2 chip in an ampoule for sulfidation or selenization; connecting the ampoule to H2S / H2Se gas, and then heating the ampoule to 300°C to 600°C to decompose the S and Se elements, thereby forming an alloy with the metal oxide WO3 or TiO2 for 1 hour to 5 hours; the atomic percentages of the S and Se elements in the resulting alloy can be mainly controlled by the time period of the oxide chip under the partial pressure of the S and Se element sources, so that in the formed photoanode material, the S element doping concentration is 5at%, and the Se element doping concentration is 1at%.

[0048] In addition, as another example, by controlling the time period, the S element doping concentration is 5 at % and the Se element doping concentration is 2 at %.

[0049] Second embodiment:

[0050] According to a second embodiment of the present disclosure, a photoanode material for producing hydrogen by electrolysis of water is provided, wherein the photoanode material comprises a metal oxide WO3 or TiO2 and two doping elements, S and Te, distributed in the metal oxide WO3 or TiO2, wherein the concentration of the S and Te doping elements may be 1at% to 10at%, and preferably the S doping concentration is 5% and the Te doping concentration is 1%.

[0051] Such a photoanode material can be prepared, for example, by the following method:

[0052] Step (A): Deposit a WO3 or TiO2 film with a thickness of 200nm to 2000nm on a substrate using PVD ion beam sputtering (IBS); the substrate is glass or sapphire coated with SnO2, or stainless steel, this type of substrate material is used for thin film deposition; the source for making the WO3 or TiO2 film is a WO3 or TiO2 target. The substrate is placed in a deposition chamber with a nominal surface temperature of about 300K. Deposition is performed by sputtering the WO3 or TiO2 target using Ar plasma. The deposition rate is controlled by adjusting the RF power of the RF and monitored by the change in thickness.

[0053] Step (B): Post-deposition annealing is performed in a heating tube with a constant oxygen flow at a temperature of about 550° C. for a time of 0.5 h to 5.0 h.

[0054] Step (C): encapsulating a metal oxide WO3 or TiO2 wafer in an ampoule for sulfidation or selenization; connecting the ampoule to H2S / H2Te gas, and then heating the ampoule to 300°C to 600°C to decompose the S and Te elements to form an alloy with the metal oxide WO3 or TiO2 for 1 hour to 5 hours; the atomic percentages of the S and Te elements in the resulting alloy can be mainly controlled by the time period of the oxide wafer under the partial pressure of the S and Te element sources.

[0055] Thus, a photoanode material is obtained, which contains metal oxide WO3 or TiO2 and doping elements S and Te, wherein the doping concentration of S can be, for example, 5 at%, and the doping concentration of Te can be, for example, 1 at%.

[0056] Third embodiment:

[0057] The above describes a photoanode material for electrolyzing water to produce hydrogen comprising a metal oxide and two Group VI doping elements, but may also comprise three doping elements. According to a third embodiment of the present disclosure, the photoanode material comprises a metal oxide such as WO3 or TiO2 and S, Se and Te doping elements distributed in the metal oxide WO3 or TiO2, wherein the concentration of the S, Se and Te doping elements is 1at% to 10at%, preferably, the doping concentration of S is 5at%, the doping concentration of Se is 1at%, and the doping concentration of Te is 1at%.

[0058] The method for preparing the photoanode material according to the third embodiment is described below. First, in step (A): a WO3 or TiO2 film with a thickness of 200nm to 2000nm is deposited on a substrate using PVD ion beam sputtering (IBS); the substrate is glass or sapphire coated with SnO2, or stainless steel, and this type of substrate material is used for thin film deposition; the source for making the WO3 or TiO2 film is a WO3 or TiO2 target. The substrate is placed in a deposition chamber with a nominal surface temperature of about 300K. Deposition is performed by sputtering the WO3 or TiO2 target using Ar plasma. The deposition rate is controlled by adjusting the RF power of the RF and monitored by the change in thickness.

[0059] Then, in step (B): post-deposition annealing is performed in a heating tube with a constant oxygen flow at a temperature of about 550° C. for a time of 0.5 h to 5.0 h.

[0060] Then, in step (C): the metal oxide WO3 or TiO2 wafer is encapsulated in an ampoule for sulfidation or selenization; the ampoule is connected to H2S / H2Se / H2Te gas, and then the ampoule is heated to 300°C to 600°C to produce decomposition of S, Se and Te elements, so that they form an alloy with the metal oxide WO3 or TiO2 for 1h to 5h; the atomic percentage of S and Se elements in the obtained alloy can be mainly controlled by the time period of the oxide wafer under the partial pressure of the S, Se and Te element sources. For example, the doping concentration of S is 5at%, the doping concentration of Se is 1at%, and the doping concentration of Te is 1at%.

[0061] Comparative Example:

[0062] As a comparative example, a photoanode material containing only S as a doping element is prepared. The photoanode material contains TiO 2 and an S doping element distributed in the metal oxide TiO 2 , wherein the concentration of the S doping element is 5 at %.

[0063] Various photoanode materials obtained by the above method were subjected to comparative tests, and the bandgap widths were obtained as shown in Table 1. In Table 1, only the case where TiO2 is used as the metal oxide is listed, but the case where WO3 is used as the metal oxide is similar, so it is not repeated.

[0064] MOx Doping elements Doping concentration Bandgap First embodiment <![CDATA[TiO2]]> S+Se 5at%(S)+1at%(Se) 2.15 First embodiment <![CDATA[TiO2]]> S+Se 5at%(S)+2at%(Se) 2.0 Second embodiment <![CDATA[TiO2]]> S+Te 5at%(S)+1at%(Te) 2.1 Third embodiment <![CDATA[TiO2]]> S+Se+Te 5at%(S)+1at%(Se)+1at%(Te) 1.95 Comparative Example <![CDATA[TiO2]]> S 5at% 2.3

[0065] It can be seen from the test results in Table 1 that the band gap of the photoanode material doped only with S is around 2.3 eV, while by doping at least two Group VI elements, the band gap can be reduced to around 2.0 eV, thereby obtaining a photoanode material that meets the performance requirements.

[0066] According to a further embodiment of the present disclosure, Figure 5 As shown, a water electrolysis hydrogen production system is provided, wherein the electrolysis hydrogen production system includes water or an aqueous solution as an electrolyte 30, a cathode 20, and an anode 10, wherein the cathode 20 contains platinum, for example, and the anode 10 includes the photoanode material described in the above embodiment of the present disclosure, including a substrate 11 and a photoanode material 12, wherein the photoanode material 12 includes a metal oxide layer, such as a thin layer of TiO2 or WO3, and at least two Group VI doping elements doped in the metal oxide, such as S, Se or Te. Under sunlight, oxygen is generated on the surface of the anode 10, and hydrogen is generated on the surface of the cathode. The generated hydrogen and oxygen can be collected by an appropriate collection system and further processed or utilized. Thus, hydrogen is directly generated by utilizing the band gap of the semiconductor material, simplifying the structure of the hydrogen production system.

[0067] Although it is described above that a metal oxide thin layer is formed on a substrate by ion beam sputtering, the present disclosure is not limited thereto, but other methods may be used, for example, PECVD, evaporation, ALD and other deposition methods, and in the case where the metal oxide thin layer is formed by other methods, the annealing of step (B) may be omitted. Regarding the doping of Group VI elements, although it is described above that it is achieved by heating an ampoule, the present disclosure is not limited thereto, and other methods such as diffusion, ion implantation, evaporation and the like may also be used to achieve it. In addition, in the above description, the photoanode materials are described by taking TiO2 and WO3 as examples, but the present disclosure is not limited thereto, for example, BaTiO3, CaTiO3 and the like may also be used as metal oxides.

[0068] Therefore, according to the present disclosure, the following embodiments are provided, including but not limited to:

[0069] Item 1. A photoanode material for producing hydrogen by electrolysis of water, comprising: an oxide MOx and at least two doping elements distributed in the oxide MOx, wherein the at least two doping elements are selected from elements in the VI main group.

[0070] Item 2. The photoanode material for producing hydrogen by electrolysis of water according to Item 1, wherein the element M in the oxide MOx is a metal element.

[0071] Item 3. The photoanode material for producing hydrogen by electrolysis of water according to Item 2, wherein the metal element is one of Ti or W.

[0072] Item 4. A photoanode material for producing hydrogen by electrolysis of water according to any one of Items 1 to 3, wherein one of the at least two doping elements is sulfur (S).

[0073] Item 5. The photoanode material for producing hydrogen by electrolysis of water according to Item 4, wherein another of the doping elements is selected from Se or Te.

[0074] Item 6. The photoanode material for producing hydrogen by electrolysis of water according to any one of Items 1 to 5, wherein the concentration of the doping element is 1 at % to 10 at %.

[0075] Item 7. The photoanode material for producing hydrogen by electrolysis of water according to any one of Items 4 to 6, wherein the doping concentration of sulfur is 5 at %.

[0076] Item 8. The photoanode material for producing hydrogen by electrolysis of water according to Item 7, wherein the doping concentration of Se or Te is 1 at% to 2 at%.

[0077] Item 9. A method for preparing a photoanode material for producing hydrogen by electrolysis of water, comprising the following steps:

[0078] Step (A): forming oxide MOx;

[0079] Step (C): alloying the oxide MOx with at least two elements selected from Group VI to form a multi-element alloy containing equivalent Group VI doping elements.

[0080] Item 10. The method for preparing a photoanode material for producing hydrogen by electrolysis of water according to Item 9, wherein M in the oxide MOx is a metal element and the oxide MOx is a metal oxide.

[0081] Item 11. The method for preparing a photoanode material for producing hydrogen by electrolysis of water according to Item 9 or 10, wherein the at least two elements of Group VI are selected from the group consisting of S, Se and Te.

[0082] Item 12. The method for preparing a photoanode material for producing hydrogen by electrolysis of water according to Item 10 or 11, further comprising:

[0083] After step (A) and before step (C), step (B) is performed: annealing the metal oxide MOx.

[0084] Item 13. A method for preparing a photoanode material for producing hydrogen by electrolysis of water according to any one of Items 10 to 12, wherein the synthesis method for forming the metal oxide MOx in step (A) comprises: depositing a metal oxide MOx thin film on a substrate by PVD ion beam sputtering (IBS).

[0085] Item 14. The method for preparing a photoanode material for producing hydrogen by electrolysis of water according to Item 13, wherein the thickness of the metal oxide MOx film is about 1.0 nm to 1.0 mm.

[0086] Item 15. A method for preparing a photoanode material for producing hydrogen by electrolysis of water according to any one of Items 12 to 14, wherein the substrate material may be glass, sapphire, or stainless steel.

[0087] Item 16. A method for preparing photoanode materials for producing hydrogen by electrolysis of water according to any one of Items 12 to 15, wherein the process conditions of step (B) are: heat treatment temperature of 300 to 1000°C, duration of 0.5h to 5.0h under continuous oxygen flow conditions.

[0088] Item 17. A method for preparing a photoanode material for producing hydrogen by electrolysis of water according to any one of Items 10 to 16, wherein step (C) comprises:

[0089] The metal oxide MOx wafer is sealed in an ampoule under vacuum conditions;

[0090] An ingot of at least two Group VI element sources is disposed in the ampoule;

[0091] The ampoule is heated in a dual-zone furnace so that the ingot is in the hot zone, generating a partial pressure of the group VI element, which forms an alloy with the metal oxide MOx.

[0092] Item 18. The method for preparing photoanode materials for producing hydrogen by electrolysis of water according to Item 17, wherein the heating duration is 1 h to 5 h.

[0093] Item 19. A method for preparing a photoanode material for producing hydrogen by electrolysis of water according to any one of Items 10 to 16, wherein step (C) comprises:

[0094] The metal oxide MOx wafer is sealed in an ampoule under vacuum conditions;

[0095] providing a gas containing at least two sources of Group VI elements to the ampoule;

[0096] Heating the ampoule causes the decomposition of the Group VI element, which forms an alloy with the metal oxide MOx.

[0097] Item 20. The method for preparing a photoanode material for producing hydrogen by electrolysis of water according to Item 19, wherein the ampoule is heated to 100°C to 1000°C.

[0098] Item 21. The method for preparing photoanode materials for producing hydrogen by electrolysis of water according to Item 19 or 20, wherein the heating duration is 1 h to 5 h.

[0099] Item 22. A system for producing hydrogen by electrolysis of water, comprising:

[0100] Water or aqueous solution;

[0101] a cathode; and

[0102] An anode, comprising the photoanode material as described in any one of items 1 to 8 or the photoanode material prepared according to the preparation method as described in any one of items 9 to 21.

[0103] From the above description, it is apparent to those of ordinary skill in the art that, although the methods and apparatus described herein constitute exemplary embodiments of the present disclosure, the present invention is not limited to these specific embodiments, and changes may be made to such embodiments without departing from the scope of the present invention as defined by the claims. In addition, it is to be understood that the present invention is defined by the claims, and this does not mean that any limitation or element describing the exemplary embodiments set forth herein will be incorporated into the interpretation of any claim element unless such limitation or element is expressly stated. Similarly, it is to be understood that not all of the mentioned advantages or purposes of the invention disclosed herein need to be met in order to fall within the scope of any claim, because the present invention is defined by the claims and because there may be inherent and / or unforeseen advantages of the claimed invention even though they may not have been explicitly discussed herein.

Claims

1. A photoanode material for producing hydrogen by electrolysis of water, comprising: An oxide MOx and at least two doping elements distributed in the oxide MOx, wherein the at least two doping elements are selected from elements in the VI main group.

2. The photoanode material for producing hydrogen by electrolysis of water according to claim 1, wherein: The element M in the oxide MOx is a metal element.

3. The photoanode material for producing hydrogen by electrolysis of water according to claim 2, wherein: The metal element is one of Ti and W.

4. The photoanode material for producing hydrogen by electrolysis of water according to any one of claims 1 to 3, wherein: One of the at least two doping elements is sulfur (S).

5. The photoanode material for producing hydrogen by electrolysis of water according to claim 4, wherein: The other of the doping elements is selected from Se or Te.

6. A method for preparing a photoanode material for producing hydrogen by electrolysis of water, comprising the following steps: Step (A): forming oxide MOx; Step (C): alloying the oxide MOx with at least two elements selected from Group VI to form a multi-element alloy containing equivalent Group VI doping elements.

7. The method for preparing a photoanode material for producing hydrogen by electrolysis of water according to claim 6, wherein: M in the oxide MOx is a metal element, and the oxide MOx is a metal oxide.

8. The method for preparing a photoanode material for producing hydrogen by electrolysis of water according to claim 6 or 7, wherein: The at least two elements of Group VI are selected from the group consisting of S, Se and Te.

9. The method for preparing a photoanode material for producing hydrogen by electrolysis of water according to claim 6 or 7, further comprising: After step (A) and before step (C), step (B) is performed: annealing the metal oxide MOx.

10. A system for producing hydrogen by electrolysis of water, comprising: Water or aqueous solution; cathode; as well as An anode, comprising the photoanode material according to any one of claims 1 to 5 or the photoanode material prepared by the preparation method according to any one of claims 6 to 9.

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