Solution-phase (e.g., homogeneous) or surface-immobilized (e.g., heterogeneous) electrode-driven oxidation catalysts based on iridium coordination compounds which self-assemble upon chemical or electrochemical oxidation of suitable precursors and methods of making and using thereof are. Iridium species such as {[Ir(LX).sub.x(H.sub.2O).sub.y(μ-O)].sub.z.sup.m+}.sub.n wherein x, y, m are integers from 0-4, z and n from 1-4 and LX is an oxidation-resistant chelate ligand or ligands, such as such as 2(2-pyridyl)-2-propanolate, form upon oxidation of various molecular iridium complexes, for instance [Cp*Ir(LX)OH] or [(cod)Ir(LX)] (Cp*=pentamethylcyclopentadienyl, cod=cis-cis,1,5-cyclooctadiene) when exposed to oxidative conditions, such as sodium periodate (NaIO.sub.4) in aqueous solution at ambient conditions.

Apparatuses and methods for performing coupled chemical and electrochemical reactions are disclosed. An electrochemical cell has a first reaction chamber configured to perform a chemical reaction and an anode chamber configured to perform an electrochemical reaction. The first reaction chamber and the anode chamber are separated by a first membrane. The first membrane acts as a cathode of the cell, a hydrogen-selective layer and a catalyst. The first membrane may comprise a layer of palladium or a palladium alloy. An ion exchange membrane separates the first membrane and the anode chamber. The chemical and electrochemical reactions may respectively be hydrogenation and dehydrogenation reactions.

Apparatuses and methods for performing coupled chemical and electrochemical reactions are disclosed. An electrochemical cell has a first reaction chamber configured to perform a chemical reaction and an anode chamber configured to perform an electrochemical reaction. The first reaction chamber and the anode chamber are separated by a first membrane. The first membrane acts as a cathode of the cell, a hydrogen-selective layer and a catalyst. The first membrane may comprise a layer of palladium or a palladium alloy. An ion exchange membrane separates the first membrane and the anode chamber. The chemical and electrochemical reactions may respectively be hydrogenation and dehydrogenation reactions.

Disclosed is an electrochemical method for continuous regeneration of a Pt.sup.IV oxidant to furnish overall electrochemical methane oxidation. Cl-adsorbed Pt electrodes catalyze facile oxidation of Pt.sup.II to Pt.sup.IV without concomitant methanol oxidation. Exploiting this electrochemistry, the Pt.sup.II/IV ratio in solution is maintained via in situ monitoring of the solution potential coupled with dynamic modulation of the electric current. Remarkably, this method leads to sustained methane oxidation catalysis with ˜70% selectivity for methanol.

Disclosed is an electrochemical method for continuous regeneration of a Pt.sup.IV oxidant to furnish overall electrochemical methane oxidation. Cl-adsorbed Pt electrodes catalyze facile oxidation of Pt.sup.II to Pt.sup.IV without concomitant methanol oxidation. Exploiting this electrochemistry, the Pt.sup.II/IV ratio in solution is maintained via in situ monitoring of the solution potential coupled with dynamic modulation of the electric current. Remarkably, this method leads to sustained methane oxidation catalysis with ˜70% selectivity for methanol.

A photocatalyst and a method for producing hydrogen and oxygen from water by photocatalytic electrolysis are disclosed. The photocatalyst includes a photoactive material and metal or metal alloy material (15)—e.g. pure particles or alloys of Au, Pd and Ag—capable of having plasmon resonance properties deposited on the surface of the photoactive material. The photoactive material includes a p-n junction (17) formed by contact of a n-type semiconductor material (10), such as mixed phase TiO2 nano particles (anatase to rutile ratio of 1.5 to 1 or greater), and a p-type semiconductor material (16), such as CoO or Cu2O.

A reactor and process capable of concurrently producing electric power and selectively oxidizing gaseous components in a feed stream, such as hydrocarbons to unsaturated products, which are useful intermediates in the production of liquid fuels. The reactor includes an oxidation membrane, a reduction membrane, an electron barrier, and a conductor. The oxidation membrane and reduction membrane include an MIEC oxide. The electron barrier, located between the oxidation membrane and the reduction membrane, is configured to allow transmission of oxygen anions from the reduction membrane to the oxidation membrane and resist transmission of electrons from the oxidation membrane to the reduction membrane. The conductor conducts electrons from the oxidation membrane to the reduction membrane.

This invention is directed to a method of oxygenating hydrocarbons with molecular oxygen, O.sub.2, as oxidant under electrochemical reducing conditions, using polyoxometalate compounds based on the so-called Keplerate capsules, such as [{(W.sup.VI)W.sup.VI.sub.5O.sub.21(SO.sub.4)}.sub.12{(Fe(H.sub.2O)).sub.30}(SO.sub.4).sub.13(H.sub.2O).sub.34].sup.32− or [{(Mo.sup.VI)Mo.sup.VI.sub.5O.sub.21)(X′.sub.1).sub.6}.sub.12{Fe.sup.III(H.sub.2O)(X.sub.1)}.sub.30] or solvates thereof as catalysts, wherein X′.sub.1 and X.sub.1 are each independently selected from H.sub.2O, Mo.sub.2O.sub.8.sup.2−, Mo.sub.2O.sub.9.sup.2−, CH.sub.3COO.sup.− (acetate), or any combination thereof.

This invention is directed to a method of oxygenating hydrocarbons with molecular oxygen, O.sub.2, as oxidant under electrochemical reducing conditions, using polyoxometalate compounds based on the so-called Keplerate capsules, such as [{(W.sup.VI)W.sup.VI.sub.5O.sub.21(SO.sub.4)}.sub.12{(Fe(H.sub.2O)).sub.30}(SO.sub.4).sub.13(H.sub.2O).sub.34].sup.32− or [{(Mo.sup.VI)Mo.sup.VI.sub.5O.sub.21)(X′.sub.1).sub.6}.sub.12{Fe.sup.III(H.sub.2O)(X.sub.1)}.sub.30] or solvates thereof as catalysts, wherein X′.sub.1 and X.sub.1 are each independently selected from H.sub.2O, Mo.sub.2O.sub.8.sup.2−, Mo.sub.2O.sub.9.sup.2−, CH.sub.3COO.sup.− (acetate), or any combination thereof.

A method for manufacturing a palladium coated doped metal oxide conducting electrode including immersing a metal oxide conducting electrode into an aqueous solution having a palladium precursor salt to form the metal oxide conducting electrode having at least one surface coated with palladium precursor. To form a layer of palladium nanoparticles on the metal oxide conducting electrode the palladium precursor on the metal oxide conducting is reduced with a borohydride compound. The palladium nanoparticles on the metal oxide conducting electrode have an average diameter of 8 nm to 22 nm and are present on the surface of the metal oxide conducting electrode at a density from 1.5×10.sup.−3 Pd.Math.nm.sup.−2 to 3.5×10.sup.−3 Pd.Math.nm.sup.−2.