Solar‐Driven Interfacial Evaporation Accelerated Electrocatalytic Water Splitting on 2D Perovskite Oxide/MXene Heterostructure

Abstract The rational design of economic and high‐performance electrocatalytic water‐splitting systems is of great significance for energy and environmental sustainability. Developing a sustainable energy conversion‐assisted electrocatalytic process provides a promising novel approach to effectively boost its performance. Herein, a self‐sustained water‐splitting system originated from the heterostructure of perovskite oxide with 2D Ti 3 C 2 T x MXene on Ni foam (La 1‐x Sr x CoO 3 /Ti 3 C 2 T x MXene/Ni) that shows high activity for solar‐powered water evaporation and simultaneous electrocatalytic water splitting is presented. The all‐in‐one interfacial electrocatalyst exhibits highly improved oxygen evolution reaction (OER) performance with a low overpotential of 279 mV at 10 mA cm −2 and a small Tafel slope of 74.3 mV dec −1 , superior to previously reported perovskite oxide‐based electrocatalysts. Density functional theory calculations reveal that the integration of La 0.9 Sr 0.1 CoO 3 with Ti 3 C 2 T x MXene can lower the energy barrier for the electron transfer and decrease the OER overpotential, while COMSOL simulations unveil that interfacial solar evaporation could induce OH − enrichment near the catalyst surfaces and enhance the convection flow above the catalysts to remove the generated gas, remarkably accelerating the kinetics of electrocatalytic water splitting.