Interface strain engineering of Ir clusters on ultrathin NiO nanosheets for electrochemical water splitting over 1800 hours

Abstract

Strain engineering of two-dimensional (2D) material interfaces represents a powerful strategy for enhancing the electrocatalytic activity of water splitting. However, maintaining catalytic stability under various harsh conditions by introducing interface strain remains a great challenge. The catalyst developed and evaluated herein comprised Ir clusters dispersed on 2D NiO nanosheets (NSs) derived from metal organic frameworks (Ir@NiO/CBDC), which displays a high activity and stability under all pH conditions, and even a change of only 1% in the applied voltage is observed after continuous electrocatalytic operation for over 1800 h under alkaline conditions. Through combined experimental and computational studies, we found that the introduced interfacial strain contributes to the outstanding structural stability of the Ir@NiO/CBDC catalyst, arising from its increased Ir and Ni vacancy formation energies, and hence suppressing its leaching. Moreover, strain also enhances the kinetically sluggish electrocatalytic water splitting reaction by optimizing its electronic structure and coordination environment. This work highlights the effects of strain on catalyst stability and provides new insights for designing widely applicable electrocatalysts.