Synergistic Effects in Earth-Abundant Bimetallic Aerogels for Enhanced Oxygen Evolution Reaction

Abstract

Inexpensive and efficient earth-abundant metal catalysts are required for electrocatalytic water splitting to meet future energy conversion and storage demand, but its practical production is limited by uncertain factors such as slow oxygen evolution reaction (OER) kinetics, low electrical conductivity, and unclear catalytic mechanism. A facile one-step reduction and in situ gelation reaction is proposed to synthesize a series of earth-abundant nickel-based bimetallic aerogels (Ni_xFe_y, Ni_xCo_y, and Ni_xCu_y) by utilizing the synergistic effect between bimetals and a surface electronic structure adjustment strategy to realize the OER performance improvement. Meanwhile, density functional theory calculations show that the introduction of transition metal Fe into Ni aerogels can cause the center of Fe d-band to shift down, induce strong electronic effects on the Ni surface, and regulate the adsorption of OER reaction intermediates (*OH, *O, and *OOH), enhancing the aerogel conductivity, thereby achieving higher intrinsic OER activity of the Ni₄₅Fe₅₅ aerogel catalyst. This work sheds light on the design of high-performance earth-abundant bimetallic aerogels electrocatalysts.