NiFe on CeO2, TiO2, and ZrO2 Supports as Efficient Oxygen Evolution Reaction Catalysts in Alkaline Media.

Abstract

The high cost and low energy efficiency of conventional water electrolysis methods continue to restrict the widespread adoption of green hydrogen. Anion exchange membrane (AEM) water electrolysis is a promising technology that can produce hydrogen using cost-effective transition-metal catalysts at high energy efficiency. Herein, we investigate the catalytic activity of nickel and iron nanoparticles dispersed on metal-oxide supports for the oxygen evolution reaction (OER), employing electrochemical testing with an anion exchange ionomer to evaluate their potential for application in AEM electrolyzers. We report the electrochemical performance of NiFe nanoparticles of varying Ni:Fe ratios on CeO₂ for OER reaction, assessing the overpotential, Tafel slope, and electrochemical stability of the catalysts. Our findings indicate that Ni₉₀Fe₁₀ has the highest catalytic activity as well as stability. To further understand the role of different supports, we assess the electrocatalytic performance of Ni₉₀Fe₁₀ nanoparticles on two more supports - TiO₂ and ZrO₂. While CeO₂ has the lowest overpotential, the other supports also show high activity and good performance at high current densities. TiO₂ exhibits superior stability and its overpotential after chronopotentiometry measurements approaches that of CeO₂ at high current densities. These results underscore the critical role of iron addition in enhancing nickel nanoparticles' catalytic activity and further emphasize the importance of metal oxide supports in improving catalyst stability and performance.