A photoelectrode includes a double-layer homojunction of metal oxide semiconductor films without heteroatoms incorporated. The metal oxide semiconductor films are uniform in large size with rich oxygen vacancies. For BiVO.sub.4 films, Bi precursor can be electrodeposited on a substrate under atmospheric pressure and air atmosphere. The electrolytes for electrodeposition are acidic or alkaline with controllable pHs. The electrodeposited substrate is transferred to the muffle furnace for thermal evaporation with V precursor. Film thickness and size can be controlled by electrodeposition parameters. The BiVO.sub.4 double-layer homojunction is a safer and cheaper material in photo-driven devices, hydrogen producers, and solar cells, and is an economical replacement of costly III-V compounds, polymers, and valuable fossil. The BiVO.sub.4 double-layer homojunction can also be employed as photoelectrodes for H.sub.2 production via photoelectrochemical (PEC) water splitting under solar light, which can provide pivotal reactor materials for hydrogen producers and solar cells.

A photoelectrode includes a double-layer homojunction of metal oxide semiconductor films without heteroatoms incorporated. The metal oxide semiconductor films are uniform in large size with rich oxygen vacancies. For BiVO.sub.4 films, Bi precursor can be electrodeposited on a substrate under atmospheric pressure and air atmosphere. The electrolytes for electrodeposition are acidic or alkaline with controllable pHs. The electrodeposited substrate is transferred to the muffle furnace for thermal evaporation with V precursor. Film thickness and size can be controlled by electrodeposition parameters. The BiVO.sub.4 double-layer homojunction is a safer and cheaper material in photo-driven devices, hydrogen producers, and solar cells, and is an economical replacement of costly III-V compounds, polymers, and valuable fossil. The BiVO.sub.4 double-layer homojunction can also be employed as photoelectrodes for H.sub.2 production via photoelectrochemical (PEC) water splitting under solar light, which can provide pivotal reactor materials for hydrogen producers and solar cells.

A photoelectrochemical system may be utilized for processing of wastewater to hydrogen. For example, a method for hydrogen production from wastewater may include: providing a photocathode electrically connected by a wire to a photocatalyst, where both the photocathode and the photocatalyst are at least partially immersed in an electrolyte solution that comprises an aqueous fluid having wastewater at least partially dissolved therein; illuminating the photocathode with first light thereby causing the photocathode to generate a first plurality of electron-electron hole pairs, wherein the photocathode comprises a silicon-based heterojunction; illuminating a photocatalyst with second light thereby causing the photocathode to generate a second plurality of electron-electron hole pairs, wherein the photocatalyst comprises a semiconductor; and photochemically converting the wastewater to hydrogen gas and oxygen.

A photoelectrochemical system may be utilized for processing of wastewater to hydrogen. For example, a method for hydrogen production from wastewater may include: providing a photocathode electrically connected by a wire to a photocatalyst, where both the photocathode and the photocatalyst are at least partially immersed in an electrolyte solution that comprises an aqueous fluid having wastewater at least partially dissolved therein; illuminating the photocathode with first light thereby causing the photocathode to generate a first plurality of electron-electron hole pairs, wherein the photocathode comprises a silicon-based heterojunction; illuminating a photocatalyst with second light thereby causing the photocathode to generate a second plurality of electron-electron hole pairs, wherein the photocatalyst comprises a semiconductor; and photochemically converting the wastewater to hydrogen gas and oxygen.

A photoelectrochemical system may be utilized for processing of hydrogen sulfide to hydrogen. For example, a method for hydrogen production from hydrogen sulfide may include: providing a photocathode electrically connected by a wire to a photocatalyst, where both the photocathode and the photocatalyst are at least partially immersed in an electrolyte solution that includes an aqueous fluid having hydrogen sulfide at least partially dissolved therein; illuminating the photocathode with first light thereby causing the photocathode to generate a first plurality of electron-electron hole pairs, wherein the photocathode includes a silicon-based heterojunction; illuminating a photocatalyst with second light thereby causing the photocathode to generate a second plurality of electron-electron hole pairs, wherein the photocatalyst includes a semiconductor; and photochemically converting the hydrogen sulfide to hydrogen gas and sulfur.

A photoelectrochemical system may be utilized for processing of hydrogen sulfide to hydrogen. For example, a method for hydrogen production from hydrogen sulfide may include: providing a photocathode electrically connected by a wire to a photocatalyst, where both the photocathode and the photocatalyst are at least partially immersed in an electrolyte solution that includes an aqueous fluid having hydrogen sulfide at least partially dissolved therein; illuminating the photocathode with first light thereby causing the photocathode to generate a first plurality of electron-electron hole pairs, wherein the photocathode includes a silicon-based heterojunction; illuminating a photocatalyst with second light thereby causing the photocathode to generate a second plurality of electron-electron hole pairs, wherein the photocatalyst includes a semiconductor; and photochemically converting the hydrogen sulfide to hydrogen gas and sulfur.

A method of promoting a chemical reaction includes immersing a device in a solution contained in a reaction chamber, the device including a substrate and a plurality of conductive projections supported by the substrate, each conductive projection of the plurality of conductive projections having a semiconductor composition, irradiating the device to drive the chemical reaction, and controlling a temperature of the solution contained in the reaction chamber such that the temperature is maintained in a temperature range closer to a boiling temperature of the solution than a freezing temperature of the solution

The present application discloses a photoelectrode and a preparation method therefor, and a Pt-based alloy catalyst and a preparation method therefor. The method for preparing the Pt-based nano-alloy catalyst includes: placing a photoelectrode in an electrolytic cell with at least one light-transmitting surface and including an electrolyte; using a light source to irradiate a surface of the photoelectrode from the light-transmitting surface of the electrolytic cell, where the photoelectrode includes an active metal layer, a passivation layer, a semiconductor light absorption layer, a rear conductive layer, and an insulating protective layer that are sequentially stacked along the light incident direction; based on an electrochemical workstation and light irradiation, using a Pt electrode and a reference electrode to match the photoelectrode to electrochemically treat the surface of the photoelectrode; and cleaning the electrochemically-treated photoelectrode to obtain the Pt-based nano-alloy catalyst and a photoelectrode modified by the Pt-based nano-alloy catalyst.

The present application discloses a photoelectrode and a preparation method therefor, and a Pt-based alloy catalyst and a preparation method therefor. The method for preparing the Pt-based nano-alloy catalyst includes: placing a photoelectrode in an electrolytic cell with at least one light-transmitting surface and including an electrolyte; using a light source to irradiate a surface of the photoelectrode from the light-transmitting surface of the electrolytic cell, where the photoelectrode includes an active metal layer, a passivation layer, a semiconductor light absorption layer, a rear conductive layer, and an insulating protective layer that are sequentially stacked along the light incident direction; based on an electrochemical workstation and light irradiation, using a Pt electrode and a reference electrode to match the photoelectrode to electrochemically treat the surface of the photoelectrode; and cleaning the electrochemically-treated photoelectrode to obtain the Pt-based nano-alloy catalyst and a photoelectrode modified by the Pt-based nano-alloy catalyst.

There is provided an electrolyte membrane that is disposed between an electrolytic solution in an oxidation tank and a reduction electrode in a reduction tank to be in contact with both the electrolytic solution and the reduction electrode and is used in a carbon dioxide reduction device which performs a carbon dioxide reduction reaction by bringing carbon dioxide into direct contact with the reduction electrode, the electrolyte membrane including: a water-repellent film on a part of a surface which is in contact with the electrolytic solution.