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.

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.

Disclosed is a carbon dioxide utilization system capable of recharging and undergoing reactions. The system includes a cathode unit provided with a first aqueous solution accommodated in a first accommodation space, and a cathode at least a part of which is submerged in the first aqueous solution; an anode unit provided with an alkaline second aqueous solution accommodated in a second accommodation space, and a metal anode at least a part of which is submerged in the second aqueous solution; and a connection unit provided with a connection channel connecting the first and second accommodation spaces in open communication, and a porous ion transfer member, disposed in the connection channel, for blocking the movement of the first and second aqueous solutions but allowing the movement of ions.

Disclosed is a carbon dioxide utilization system capable of recharging and undergoing reactions. The system includes a cathode unit provided with a first aqueous solution accommodated in a first accommodation space, and a cathode at least a part of which is submerged in the first aqueous solution; an anode unit provided with an alkaline second aqueous solution accommodated in a second accommodation space, and a metal anode at least a part of which is submerged in the second aqueous solution; and a connection unit provided with a connection channel connecting the first and second accommodation spaces in open communication, and a porous ion transfer member, disposed in the connection channel, for blocking the movement of the first and second aqueous solutions but allowing the movement of ions.

The electrode catalyst ink for a water electrolysis cell includes a catalyst including a layered double hydroxide, an organic polymer, and a solvent. The Hansen solubility parameter distance R.sub.a1 between the solvent and the catalyst is 15.0 MPa.sup.½ or more and less than 20.5 MPa.sup.½. The Hansen solubility parameter distance R.sub.a2 between the solvent and the organic polymer is 10.0 MPa.sup.½ or more and 14.0 MPa.sup.½ or less.

The electrode catalyst ink for a water electrolysis cell includes a catalyst including a layered double hydroxide, an organic polymer, and a solvent. The Hansen solubility parameter distance R.sub.a1 between the solvent and the catalyst is 15.0 MPa.sup.½ or more and less than 20.5 MPa.sup.½. The Hansen solubility parameter distance R.sub.a2 between the solvent and the organic polymer is 10.0 MPa.sup.½ or more and 14.0 MPa.sup.½ or less.

Electrochemical cells for the oxidation of 5-hydroxymethylfurfural are provided. Also provided are methods of using the cells to carry out the oxidation reactions. The electrochemical cells and methods use catalytic copper-based anodes to carry out the electrochemical oxidation reactions.

Electrochemical cells for the oxidation of 5-hydroxymethylfurfural are provided. Also provided are methods of using the cells to carry out the oxidation reactions. The electrochemical cells and methods use catalytic copper-based anodes to carry out the electrochemical oxidation reactions.

A cathode is provided for electrolysis of water wherein the cathode material comprises a multi-principal element, transition metal dichalcogenide material that has four or more chemical elements and that is a single phase, solid solution. The pristine cathode material does not contain platinum as a principal (major) component. However, a cathode comprising a transition metal dichalcogenide having platinum (Pt) nanosized islands or precipitates disposed thereon is also provided.

A cathode is provided for electrolysis of water wherein the cathode material comprises a multi-principal element, transition metal dichalcogenide material that has four or more chemical elements and that is a single phase, solid solution. The pristine cathode material does not contain platinum as a principal (major) component. However, a cathode comprising a transition metal dichalcogenide having platinum (Pt) nanosized islands or precipitates disposed thereon is also provided.