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Cu_xCo_3-xO₄ ultra-thin film as efficient anodic catalysts for anion exchange membrane water electrolysers

ICMS

E. López-Fernández, J. Gil-Rostra, J.P. Espinós, A.R. González-Elipe, F. Yubero, A. de Lucas-Consuegra Journal of Power Sources 2019, Vol. 415, 136-144

Cu_xCo_3-xO₄ ultra-thin films, deposited by magnetron sputtering at oblique angles have been used as anodic catalysts in anion exchange membrane water electrolysers. It has been demonstrated that the used deposition procedure provides porous and amorphous samples with a strict control of the total catalyst load and Co/Cu ratio. Electrocatalytic tests showed a maximum performance for the oxygen evolution reaction at Co/Cu atomic ratio around 1.8. The optimized anodic catalyst presented a long-term stability confirmed by accelerated lifetime tests together with the chemical surface analysis of the used samples. The effect of the crystallization of a single layer Cu_xCo_3-xO₄ and a multilayer (CuO/Co₃O₄)n anodic catalyst samples was also investigated. The loss of catalytic performance found in both cases may prove that a particular local chemical environment around the Co and Cu sites acts as an efficient catalytic site for the oxygen evolution reaction. A catalyst film with the optimum Co/Cu atomic ratio was incorporated into a Membrane Electrode Assembly, using a sputtered Ni film as cathode. Current density values up to 100 mA cm^-2 at 2.0 V were obtained in 1.0 M KOH electrolyte. Upon normalization by the amount of catalyst, this performance is one of the highest reported in literature. 

 

Ester López