A surface reconstruction approach using nonprecious zirconium-enriched nanosheets on NiCo nanowire catalysts with an iron foam substrate for water splitting

Abstract

The selection of active materials and substrates for electrocatalysts significantly influences water splitting efficiency under extreme operating conditions. In this study, we prepared nonprecious zirconium-enriched flake-like nanosheets on a NiCo nanowire using an iron foam substrate, where surface reconstruction occurs during the long-term water splitting process. This design catalyst synergistically combines active metal components (Ni–Co–Fe) with Zr incorporation, enhancing mass transport by creating hydrophilic surfaces for electrolyte adsorption and hydrophobic surfaces for gas bubble release. The ZrFe–NiCo/IF catalysts demonstrate exceptional HER and OER over a period of 100 h at 500 mA cm⁻², with a reduced overpotential of 350 mV observed at 10 mA cm⁻² for the overall water splitting. Impressively, the catalyst operates steadily at 500 mA cm⁻² for 866 h and during long-term operation, surface reconstruction occurs after 200 h, exposing additional accessible active sites that sustain stable performance. Remarkably, in a large-scale alkaline water electrolyzer, ZrFe–NiCo/IF operates at 1.95 V for 233 h at 500 mA cm⁻². Therefore, this work introduces a promising approach to designing Zr-enriched, non-precious electrocatalysts with exceptional water splitting performance and controlled surface reconstruction under extreme conditions.