Rafael Abargues López, Jaume Noguera Gómez, Juan P. Martínez Pastor (Universitat de València); Pedro Javier Rodríguez Cantó (Intenanomat S.L.); Sixto Giménez Julia, Miguel García Tecedor (Universitat Jaume I).
Nowadays, there is a growing need in promoting the development of clean and renewable energies to combat climate change. However, one of the most important challenge is the efficient production of clean fuels like H2 from the hydrolysis of water. The use of H2 as a fuel is one of the most promising solutions for electricity generation as the H2 combustion with O2 is completely clean because H2O is the only product of the reaction. This is carried out in a fuel cell. The hydrolysis of water is a spontaneous process only at very high temperatures, around 2200ºC. Electrolysis of water is the most promising alternative in terms of sostenibility. However, electrolysis of water at room temperature requires a large amount of extra energy, compared to the theoretically necessary to carry it out (+1.23V). This is because, as in any chemical reaction, it is necessary to overcome the activation energy of the reaction. Electrocatalysts can be used to reduce the energy required. Although the use of photoelectrochemistry in hydrogen production processes has enormous potential, it has not yet been possible to develop an application capable of competing economically with conventional procedures. Currently, the best performing electrocatalytic systems are based on the use of precious metals (RuOx, IrOx, or Pt) that are highly expensive. Furthermore, methane reforming allows a cheap hydrogen production (3€/kg), but with an important carbon footprint that must be eliminated. Therefore, there is a need to develop new catalysts based on metals more abundant in the land surface.
Researchers from the Universitat de València in collaboration with researches from the Universitat Jaume I and Intenanomat S.L. have developed a novel material based on non-stoichiometric nickel oxide (NiOx) that possesses excellent electrocatalytic properties for the electrolysis (oxidation) of water. This compound is overtaking even the efficiencies of electrocatalysts based on precious metals (RuOx, IrOx, or Pt). The technology allows the synthesis of the electrocatalyst through the formulation of various NiOx precursors. These precursors are prepared in solutions for the deposition on different types of substrates in a single step by different printing techniques. The resulting material has excellent electrocatalytic properties for water oxidation with low energy requirements. The manufacturing method used is also completely scalable and compatible with roll-to-roll manufacturing techniques, where flexible substrates or thin metal sheets are required.
The invention would be applicable in electrocatalysts: for hydrolysis of water and in electrochloration and purification of water and in fuel cells for the generation of electricity from H2 and O2. Also can be used in the formulation of coatings and paints with photocatalytic properties and in materials for selective hole transport layers for photovoltaics and optoelectronics such as LEDs.
The proposed system has significant advantages over established systems: