A method for ambient-temperature synthesis of a catalyst for water electrolysis by dissolving an amount of an Fe.sup.2+ source and optionally an amount of a salt of another divalent cation in deionized water at ambient temperature to form a solution, placing nickel (Ni) foam into the solution, whereby the Ni foam serves as a substrate and/or a Ni source for growth of the catalyst, leaving the Ni foam in the solution at ambient temperature for a time duration in a range of from about 0.5 hour to about 4 hours to provide a treated foam, during which time duration, the catalyst is grown on the substrate, and removing the treated foam from the solution after the time duration, wherein the treated foam comprises the catalyst grown thereon.

A method for ambient-temperature synthesis of a catalyst for water electrolysis by dissolving an amount of an Fe.sup.2+ source and optionally an amount of a salt of another divalent cation in deionized water at ambient temperature to form a solution, placing nickel (Ni) foam into the solution, whereby the Ni foam serves as a substrate and/or a Ni source for growth of the catalyst, leaving the Ni foam in the solution at ambient temperature for a time duration in a range of from about 0.5 hour to about 4 hours to provide a treated foam, during which time duration, the catalyst is grown on the substrate, and removing the treated foam from the solution after the time duration, wherein the treated foam comprises the catalyst grown thereon.

A hydrogen ammonia producing device is configured to produce hydrogen and/or ammonia. The hydrogen ammonia producing device includes an electrochemical cell including an electrode assembly and an electrolyte solution. The electrode assembly has a cathode, a separator and an anode that are sequentially stacked with each other. The anode is in contact with urea. The electrolyte solution is an alkaline aqueous solution. At least one of the anode or the cathode is in contact with the electrolyte solution. The separator is an ion exchange membrane.

Disclosed herein is a method and apparatus for producing hydrogen and oxygen from water, more particularly, for decomposing water molecular bonds using resonant waves. The produced hydrogen gas may be used as a fuel, and the released oxygen gas may be used as an oxidant.

Disclosed herein is a method and apparatus for producing hydrogen and oxygen from water, more particularly, for decomposing water molecular bonds using resonant waves. The produced hydrogen gas may be used as a fuel, and the released oxygen gas may be used as an oxidant.

A method of generating electrical power or hydrogen from thermal energy is disclosed. The method includes separating, by a selectively permeable membrane, a first saline solution from a second saline solution, receiving, by the first saline solution and/or the second saline solution, thermal energy from a heat source, and mixing the first saline solution and the second saline solution in a controlled manner, capturing at least some salinity-gradient energy as electrical power as the salinity difference between the first saline solution and the second saline solution decreases. The method further includes transferring, by a heat pump, thermal energy from the first saline solution to the second saline solution, causing the salinity difference between the first saline solution and the second saline solution to increase.

A method of generating electrical power or hydrogen from thermal energy is disclosed. The method includes separating, by a selectively permeable membrane, a first saline solution from a second saline solution, receiving, by the first saline solution and/or the second saline solution, thermal energy from a heat source, and mixing the first saline solution and the second saline solution in a controlled manner, capturing at least some salinity-gradient energy as electrical power as the salinity difference between the first saline solution and the second saline solution decreases. The method further includes transferring, by a heat pump, thermal energy from the first saline solution to the second saline solution, causing the salinity difference between the first saline solution and the second saline solution to increase.

Various examples are directed to a solar power electrolyzer system comprising a first electrolyzer stack, a second electrolyzer stack, a first converter and a first converter controller. The first electrolyzer stack may be electrically coupled in series with a photovoltaic array. The first converter may be electrically coupled in series with the first electrolyzer stack and electrically coupled in series with the photovoltaic array. The second electrolyzer stack electrically may be coupled at an output of the first converter. The first converter controller may be configured to control a current gain of the first converter.

Various examples are directed to a solar power electrolyzer system comprising a first electrolyzer stack, a second electrolyzer stack, a first converter and a first converter controller. The first electrolyzer stack may be electrically coupled in series with a photovoltaic array. The first converter may be electrically coupled in series with the first electrolyzer stack and electrically coupled in series with the photovoltaic array. The second electrolyzer stack electrically may be coupled at an output of the first converter. The first converter controller may be configured to control a current gain of the first converter.

A system such as a hydrogen refueling station and a method are provided. The system includes a cryotank for storing a liquefied fuel having liquid and vapor phases, a pump for providing a first stream of the liquefied fuel in the liquid phase from the cryotank, a heat exchanger for converting at least a portion of the first stream to a gaseous fuel, a dispenser for dispensing at least a portion of the gaseous fuel to a receiving fuel tank, a refrigeration unit integrated with the heat exchanger, and a backup power unit. The refrigeration unit and the heat exchanger exchange heat with each other, and the refrigeration unit provides cooling capacity to a facility of environment where cooling is needed. The backup power unit generate electric power by using a second stream of the liquefied fuel in the vapor phase or in the liquid phase or both.