Interfacial stress induced by the adaptive construction of hydrangea-like heterojunctions based on in situ electrochemical phase reconfiguration for highly efficient oxygen evolution reaction at high current density

Abstract

Activating the redox chemistry of transition metal catalysts to dynamically construct adaptive heterojunctions while incorporating lattice mismatch-induced interfacial stress/lattice strain is critical for designing electrocatalysts with high water oxidation activity. Here, we perform electrochemically induced surface reconstruction of an adaptive hydrangea-like heterojunction (NS/NOOH), where crystalline NiOOH is epitaxially grown on the surface of NiSe nanorods (NS) to induce lattice mismatch and then generate interfacial stress. This lattice strain combined with the sufficient exposure of electrochemically active sites gifted by the hydrangea-like structure and the synergistic interfacial effect between the phases endows NS/NOOH-30 with a 25-fold and 30-fold improvement in OER performance compared with the NS/NOOH counterpart without stress during the initial cycle and original NS, respectively. Only 260 mV of overpotential is required even at high current densities (j = 500 mA cm⁻²), which meets the industrial requirements. This work demonstrates the importance of in situ surface phase transitions of electrocatalysts to generate interfacial stress and provide new insight into lattice engineering. These new insights also open up the possibility of developing highly active heterojunction catalysts through selected surface reconstruction processes.