Abstract: A nanocomposite electrode includes a porous copper substrate, Co3O4 and/or Cu/Co(OH)x nanoparticles electrolytically deposited on the porous copper substrate. Fabricating the nanocomposite electrode includes contacting the porous copper substrate with a solution comprising cobalt, and electrodepositing the cobalt on the porous copper substrate to yield the nanocomposite electrode. Reducing nitrate to ammonia includes contacting the nanocomposite electrode with an aqueous solution comprising nitrate, and electrocatalytically reducing the nitrate to yield ammonia.

Abstract: A water-disinfecting apparatus includes a vessel with a cathode, an insert with a photoanode, an ultraviolet light source configured to be positioned in the insert, and a power source. The cathode forms an electrically conductive layer on an inner surface of the vessel. The photoanode is configured to be positioned in the cathode. The power source is configured to be operably coupled to the cathode, the photoanode, and the light source.

Abstract: A nanocomposite electrode includes a porous copper substrate and platinum nanoparticles electrolytically deposited on the porous copper substrate. Making a nanocomposite electrode includes contacting a porous copper substrate with a solution including platinum, and electrodepositing the platinum on the porous copper substrate.

Abstract: A water-disinfecting apparatus includes a vessel with a cathode, an insert with a photoanode, an ultraviolet light source configured to be positioned in the insert, and a power source. The cathode forms an electrically conductive layer on an inner surface of the vessel. The photoanode is configured to be positioned in the cathode. The power source is configured to be operably coupled to the cathode, the photoanode, and the light source.

Abstract: An electrode includes an electrically conductive substrate with a coating containing boron-doped diamond (BDD) nanoparticles. Fabricating the electrode can include dispersing BDD nanoparticles in a solvent to yield a suspension, coating a conductive substrate with the suspension, and drying the suspension to yield the electrode. In some cases, fabricating the electrode includes combining BDD nanoparticles with a polymeric resin precursor to yield a mixture including a metal oxide, coating a conductive substrate with the mixture to yield a coated substrate, and calcining the coated substrate to yield a metal oxide coating including BDD nanoparticles.

Abstract: A coated optical fiber coupled to a light source for inactivating pathogens on surfaces or in water. The coated optical fiber includes a substantially UV-transparent core, particles optically coupled to the core, and a substantially UV-transparent polymer coating in contact with the particles. Coating the optical fiber includes optically coupling particles to a surface of an optical fiber core to yield a functionalized core, coating the functionalized core with a polymerizable material, and polymerizing the polymerizerable material to yield a substantially UV-transparent polymer coating on the functionalized core.