Electrochemical promotion of a dispersed Ni catalyst for H2 production via partial oxidation of methanol

This study reports the electrochemical promotion (EPOC) of Ni particles dispersed in a diamond-like carbon (DLC) matrix. A Ni-DLC (Ni/C molar ratio of 0.1) catalyst film was prepared on a K-βAl₂O₃ (K⁺-conductor) solid electrolyte by cathodic arc deposition (CAD). This physical vapour deposition (PVD) technique allows to decrease the metal loading used in the solid electrolyte cell and to electrochemically activate dispersed Ni particles in the methanol partial oxidation (POM) reaction by in-situ controlling the coverage of K⁺ ions electrochemically transferred to the catalyst surface. As compared with a pure Ni layer prepared by the same technique, the Ni-DLC catalyst film shows a higher specific activity and an improved oxidation resistance under EPOC working reaction conditions. The possibility of electrochemically activate (with a negligible energy consumption) dispersed particles of a non-noble metal catalyst (closely related to commercially catalyst formulations) is of great interest for a further commercialization step of the EPOC phenomena in H₂ production reactions and in other catalytic systems.