Seamless construction of self-supporting nanoporous FeCoZn alloy as one highly efficient electrocatalyst for oxygen evolution reaction in alkaline media

Abstract

Exploring high-efficient and economical electrocatalyst for oxygen evolution reaction (OER) is critical for the electrocatalytic water splitting technology to hydrogen production. Herein, we report a hierarchical nanoporous FeCoZn alloys with different Fe/Co atomic ratios in-situ constructed on bimodal porous NiZn intermetallic and Ni heterojunction over nickel foam (FeCoZn/NF) through a scalable electroplating-annealing-etching strategy. The synergistic effect between multi-elements, multiple interface coupling, and self-supporting seamless porous architecture is beneficial for enhancing the number of active sites but also promoting efficient mass transport and electron transfer. FeCoZn/NF exhibits the superior electrocatalytic activity toward OER with a low overpotential of 440 mV at 1004 mA cm⁻² and small Tafel slope of 84.8 mV dec⁻¹. The as-made sample also shows exceptional long-term catalytic stability in alkaline media with 1.0 M KOH of remained under the overpotential of 350 mV for 100 h. Besides, the combined FeCoZn/NF and Pt/C/NF for overall water splitting needs the cell potential of 1.481 V at 10 mA cm⁻², along with long-term stability. This work provides implications for the design and preparation of highly active non-noble metal-based multiple alloy electrocatalysts.