An electrochemical cell includes an electrolyte arranged between a hydrogen electrode and an oxygen electrode. The electrolyte contains a ceria-based material having a fluorite crystal structure and a stabilized zirconia-based material. The electrolyte may include a first electrolyte located on a side close to the hydrogen electrode and containing the ceria-based material. The electrolyte may further include a second electrolyte located on a side close to the oxygen electrode and containing the ceria-based material. The electrolyte may further include a third electrolyte located between the first electrolyte and the second electrolyte and containing the stabilized zirconia-based material.

A system embodiment includes, but is not limited to, a solid structure configure to contact each of a material in a liquid phase and a material in a vapor phase, the solid structure including a plurality of microstructures protruding at angles relative to a horizontal plane; and a layer of nanoparticles positioned on the plurality of microstructures, the layer of nanoparticles having a composition that is at least one of a same material as the plurality of microstructures and an oxide of the same material as the plurality of microstructures, the plurality of microstructures defining one or more valleys, each of the one or more valleys positioned between the layer of nanoparticles of adjacent microstructures of the plurality of microstructures, the one or more valleys configured to govern at least one of a size and a shape of a bubble of the material in the vapor phase.

Systems and methods for providing alternative fuel, in particular hydrogen photocatalytically generated by a system comprising photoactive nanoparticles and a nitrogenase cofactor are provided. In one aspect, the system includes a water soluble cadmium selenide nanoparticle (CdSe) surface capped with mercaptosuccinate (CdSe-MSA) and a NafY.FeMo-co complex comprising a NafY protein and an iron-molybdenum cofactor (FeMo-co), wherein the CdSe-MSA and NafY.FeMo-co complex are present in about 1:2 to 1:10 molar ratio.

Disclosed herein are doped perovskite oxides. The doped perovskite oxides may be used as a cathode material in an electrochemical cell to electrochemically generate ammonia from N.sub.2. The doped perovskite oxides may be combined with nitride compounds, for instance iron nitride, to further increase the efficiency of the ammonia production.

A method of producing hydrogen gas comprises introducing gaseous water to an electrolysis cell comprising a positive electrode, a negative electrode, and a proton conducting membrane between the positive electrode and the negative electrode. The proton conducting membrane comprises an electrolyte material having an ionic conductivity greater than or equal to about 10.sup.2 S/cm at one or more temperatures within a range of from about 150 C. to about 650 C. The gaseous water is decomposed using the electrolysis cell. A hydrogen gas production system and an electrolysis cell are also described.

A method of carbon dioxide hydrogenation comprises introducing gaseous water to a positive electrode of an electrolysis cell comprising the positive electrode, a negative electrode, and a proton-conducting membrane between the positive electrode and the negative electrode. The proton-conducting membrane comprises an electrolyte material having an ionic conductivity greater than or equal to about 102 S/cm at one or more temperatures within a range of from about 150 C. to about 650 C. Carbon dioxide is introduced to the negative electrode of the electrolysis cell. A potential difference is applied between the positive electrode and the negative electrode of the electrolysis cell to generate hydrogen ions from the gaseous water that diffuse through the proton-conducting membrane and hydrogenate the carbon dioxide at the negative electrode. A carbon dioxide hydrogenation system is also described.

Embodiments of the present disclosure describe methods and systems using a hydride-forming Group VI transition metal chalcogenide catalyst, such as MoSx, for selective electrocatalysis of enzyme cofactor regeneration. In particular, a method of electrochemical cofactor regeneration comprising: holding an electrode comprising a Group VI transition metal chalcogenide catalyst at a potential sufficient to form a metal hydride in an aqueous electrolyte solution; and contacting the electrode with an oxidized cofactor to reduce the cofactor, is provided. The reduced cofactor can be used by a cofactor-dependent oxidoreductase to convert a substrate to a desired product and subsequently regenerated.

The present invention relates to the use of a composition of formula (I): Fe.sub.9-a-b-cNi.sub.aCo.sub.bM.sub.cS.sub.8-dSe.sub.d, wherein M stands for one or more elements having in the ionic state an effective ionic radius in the range of 70-92 pm, a is a number within the range of 2.5?a?3.5, more preferably 2.7?a?3.3, b is a number within the range of 1.5?b?5.0, more preferably 1.5?b?4.0, most preferably 2.5?b?3.5, c is a number within the range of 0.0?c?2.0, more preferably 0.0?c?1.0, d is a number within the range of 0.0?d?4.0, more preferably 0.0?d?1.0, wherein the sum of a, b and c is in the range of 5?a+b+c?8 and wherein ?90 wt. % of the composition is in the pentlandite phase for electrocatalytic splitting of water, preferably for hydrogen evolution reaction.

The present invention relates to the use of a composition of formula (I): Fe.sub.9-a-b-cNi.sub.aCo.sub.bM.sub.cS.sub.8-dSe.sub.d, wherein M stands for one or more elements having in the ionic state an effective ionic radius in the range of 70-92 pm, a is a number within the range of 2.5?a?3.5, more preferably 2.7?a?3.3, b is a number within the range of 1.5?b?5.0, more preferably 1.5?b?4.0, most preferably 2.5?b?3.5, c is a number within the range of 0.0?c?2.0, more preferably 0.0?c?1.0, d is a number within the range of 0.0?d?4.0, more preferably 0.0?d?1.0, wherein the sum of a, b and c is in the range of 5?a+b+c?8 and wherein ?90 wt. % of the composition is in the pentlandite phase for electrocatalytic splitting of water, preferably for hydrogen evolution reaction.

Methods of producing sodium hydroxide (NaOH) or lithium hydroxide (LiOH), and sulfuric acid (H.sub.2SO.sub.4), include generating sodium sulfate (Na.sub.2SO.sub.4) or lithium sulfate (Li.sub.2SO.sub.4) from battery manufacturing and recycling and converting the generated Na.sub.2SO.sub.4 or Li.sub.2SO.sub.4 to NaOH, LiOH, and H.sub.2SO.sub.4 via an electrochemical salt-splitting process. The processing steps can be carried out in a closed system such that the generated Na.sub.2SO.sub.4 or Li.sub.2SO.sub.4 can be used in the conversion process with optional purification steps. In particular, the LiOH, NaOH, and Na.sub.2SO.sub.4 are recycled into battery recycling or battery manufacturing processes.