A wastewater to chemical fuel conversion device is provided that includes a housing having a first chamber and a second chamber, where the first chamber includes a bio-photoanode, where the second chamber includes a photocathode, where a backside of the bio-photoanode abuts a first side of a planatized fluorine doped tin oxide (FTO) glass, where a backside of the photocathode abuts a second side of the FTO glass, where a proton exchange membrane separates the first chamber from the second chamber, where the first chamber includes a wastewater input and a reclaimed water output, where the second chamber includes a solar light input and a H.sub.2 gas output, where the solar light input is disposed for solar light illumination of the first chamber and the second chamber.

One aspect of the invention provides a photoelectrochemical device including at least one electrochemical cell comprising an anode electrode and a cathode electrode; and a photovoltaic module integrated with the at least one electrochemical cell and adapted for converting energy of photons to electrical energy for driving the at least one electrochemical cell to facilitate redox reactions therein.

One aspect of the invention provides a photoelectrochemical device including at least one electrochemical cell comprising an anode electrode and a cathode electrode; and a photovoltaic module integrated with the at least one electrochemical cell and adapted for converting energy of photons to electrical energy for driving the at least one electrochemical cell to facilitate redox reactions therein.

A method for controllably making catalysts with at least one metallic surface state, that includes: a) identifying all the topological insulators in the ICSD, b) calculating the Real Space Invariants of the valence bands for all these topological insulators in order to c) identify in all these topological insulators the Wyckoff Positions where the irreducible Wannier Charge Centers (WCCs) are localized, and then d) selecting as potentially catalytic active compound a topological insulator in which the position of WCCs is not occupied by any atom; e) synthesizing a crystal of the selected potentially catalytic active compound either so that it is grown in a predefined crystallographic direction (characterized by its Miller indices (h,k,l)) which exposes the metallic surface state; or cutting the crystal in a predefined crystallographic direction (characterized by its Miller indices (h,k,l)), so that the metallic surface state is exposed when

[00001]$\left(\left(\{\begin{array}{c}\left(h,k,l\right).Math.\left(x-X_j,y-Y_j,z-Z_j\right)=0,\\ \left(h,k,l\right).Math.\left(x-x_i,y-y_i,z-z_i\right)\ne 0,\\ h,k,lϵZ\end{array}\right)\right)$

A device for catalytic conversion of carbon dioxide (CO.sub.2) includes a substrate having a surface, an array of conductive projections supported by the substrate and extending outward from the surface of the substrate, each conductive projection of the array of conductive projections having a semiconductor composition, and a plurality of nanoparticles disposed over the array of conductive projections, each nanoparticle of the plurality of nanoparticles being configured for the catalytic conversion of carbon dioxide (CO.sub.2). Each nanoparticle of the plurality of nanoparticles includes a metal sulfide, the metal sulfide including a d-block metal.

A device for catalytic conversion of carbon dioxide (CO.sub.2) includes a substrate having a surface, an array of conductive projections supported by the substrate and extending outward from the surface of the substrate, each conductive projection of the array of conductive projections having a semiconductor composition, and a plurality of nanoparticles disposed over the array of conductive projections, each nanoparticle of the plurality of nanoparticles being configured for the catalytic conversion of carbon dioxide (CO.sub.2). Each nanoparticle of the plurality of nanoparticles includes a metal sulfide, the metal sulfide including a d-block metal.

A method for producing a nitride semiconductor photoelectrode includes: a first step of forming an n-type gallium nitride layer on an electrically insulative or conductive substrate; a second step of forming an indium gallium nitride layer on the n-type gallium nitride layer; a third step of forming a p-type nickel oxide layer on the indium gallium nitride layer; and a fourth step of subjecting a nitride semiconductor in which the p-type nickel oxide layer has been formed to heat treatment.

A device for performing electrolysis of water is disclosed. The device comprising: a semiconductor structure comprising a surface and an electron guiding layer below said surface, the electron guiding layer of the semiconductor structure being configured to guide electron movement in a plane parallel to the surface, the electron guiding layer of the semiconductor structure comprising an InGaN quantum well or a heterojunction, the heterojunction being a junction between AlN material and GaN material or between AlGaN material and GaN material; at least one metal cathode arranged on the surface of the semiconductor structure; and at least one photoanode arranged on the surface of the semiconductor structure, wherein the at least one photoanode comprises a plurality of quantum dots of In.sub.xGa.sub.(1−x)N material, wherein 0.4≤x≤1. A system comprising such device is also disclosed.

A CaTiO.sub.3—TiO.sub.2 composite electrode and method of making is described. The composite electrode comprises a substrate with an average 2-12 μm thick layer of CaTiO.sub.3—TiO.sub.2 composite particles having average diameters of 0.2-2.2 μm. The method of making the composite electrode involves contacting the substrate with an aerosol comprising a solvent, a calcium complex, and a titanium complex. The CaTiO.sub.3—TiO.sub.2 composite electrode is capable of being used in a photoelectrochemical cell for water splitting.

A CaTiO.sub.3—TiO.sub.2 composite electrode and method of making is described. The composite electrode comprises a substrate with an average 2-12 μm thick layer of CaTiO.sub.3—TiO.sub.2 composite particles having average diameters of 0.2-2.2 μm. The method of making the composite electrode involves contacting the substrate with an aerosol comprising a solvent, a calcium complex, and a titanium complex. The CaTiO.sub.3—TiO.sub.2 composite electrode is capable of being used in a photoelectrochemical cell for water splitting.