Developing an FexCoyLaz-based amorphous aerogel catalyst for the oxygen evolution reaction via high throughput synthesis

Abstract

Electrochemical water splitting provides clean and sustainable hydrogen. The industrial demand for electrolysis-generated hydrogen requires efficient and affordable oxygen evolution reaction (OER) electrocatalysts. Few studies have systematically examined the synergistic impact of various elements in multi-principal-element catalysis. We developed Fe_xCo_yLa_z-containing ternary amorphous aerogel electrocatalysts via high-throughput fabrication to fulfil this research need. Stoichiometric evaluation over 70 varying compounds of Fe_xCo_yLa_z identified several high-performing compositions, such as Fe₂Co₆La₂, with an η_onset of 201 mV, η₁₀ of 209 mV, η₁₀₀ of 319 mV, and Tafel slope of 49.84 mV dec⁻¹. In addition, its catalytic stability and mass activity outperform those of a commercial catalyst, RuO₂. After investigating the catalytic roles of each constituent elements in the ternary compounds via factor rating and numerical fitting, it is concluded that the valence state of Co and its evolution directly impact the catalytic activity of the ternary compound, while Fe affects the valence state of Co, and La alters the coordination environment around the active sites, improving the catalytic stability especially at high current densities. This work suggests a feasible approach to screen out high-performance non-noble-metal electrocatalysts for effective water-splitting. Furthermore, the analytic models employed in this work put forward a new path for investigating synergistic catalytic effects in multi-principal-element electrocatalysts.