An electronic structure tailored all non-precious Zn-promoted FeCo alloy anchored on a porous N-doped carbon aerogel by thermal reduction for boosting the oxygen evolution reaction

Abstract

The development of cost-effective and highly active electrocatalysts for the oxygen evolution reaction (OER) is essential for advancing clean energy and energy storage systems. Herein, we prepared a novel Zn-promoted FeCo alloy anchored on an N-doped carbon aerogel (Zn-FeCo@NCA) derived from cellulose aerogel as an efficient and stable electrocatalyst using high-temperature carbothermal reduction. This process provides a solution to the problem of limiting the industrialization of metal aerogels by employing traditional chemical reductants and enhances cost-effectiveness due to the use of non-precious metals. The Zn-FeCo@NCA aerogel displays excellent OER activity with a low overpotential of 270 mV (10 mA cm⁻²) and a high mass activity of 0.429 A mg⁻¹, surpassing most commercial precious metal catalysts. Electrochemical in situ Raman spectroscopy indicates that Zn-FeCo@NCA undergoes self-reconfiguration during the OER to form CoOOH as a truly catalytically active species. Moreover, density functional theory (DFT) calculations further demonstrate that this modulated electronic structure favors the reduction of the adsorption energy of the intermediate O*, thereby accelerating the electron transfer kinetics and enhancing the OER activity. When integrated into an anion-exchange membrane water electrolyzer (AEMWE), the Zn-FeCo@NCA anode achieves a current density of 1000 mA cm⁻² at 2.18 V per cell, outperforming commercial RuO₂. In conclusion, benefiting from the optimized electronic interactions between Zn-promoted FeCo alloys and N-doped carbon aerogels, as well as the “pearl-like” hierarchical structure, large specific surface area, and high electrical conductivity, Zn-FeCo@NCA is expected to be an ideal candidate for the anode of AEMWEs.