Investigation of Vacuum Plasma Spraying (VPS) Coated Anodes for Alkaline Water Electrolysis

Abstract

Hydrogen has been pointed out to be the energy source of the future. So far its production was estimated to derivate 96 % from fossil fuels. However, the increase of environmental problems and the dwindling of the oil reserves are two big reasons to change the hydrogen production. The alkaline water electrolysis, associated with renewable energies, has been reported as one way to solve the problems of hydrogen production and in parallel resolving the intermittent availability of renewable electrical power. But, to become effective and economically attractive, it is necessary to develop high-performance electrocatalytical electrodes that are suitable for the intermittent process. Raney nickel (Raney-Ni) is one of the most promising electrocatalytic materials. The addition of different compounds into Raney-Ni electrodes can improve its catalytic efficiency as well as its longterm stability. Despite the variety of coated electrodes preparation, Vacuum Plasma Spraying (VPS) has shown to originate the best electrochemical performance electrodes in alkaline water electrolysis. Due to the slow kinetics of the oxygen evolution reaction (OER), the development and optimization of anode electrodes is of critical importance. Electrochemical measurements and analytical analysis were made to study the catalytic efficiency and long-term stability of adding to Raney-Ni electrode perovskite (La0.6Sr0.4CoO3 (LSCoO3 or LSC) and La0.6Sr0.4Fe0.8Co0.2O3 (LSCF)), cobalt oxide (Co3O4) and NiAlMo (nickel aluminium molybdenum). The final results show that adding perovskite and cobalt oxide to Raney-Ni improved the catalytic efficiency and long-term stability. However, further tests must be done to assess the effective logterm stability of the proposed Raney-Ni modifications.