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

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 Ti3C2Tx MXene on Ni foam (La1‐xSrxCoO3/Ti3C2Tx 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 La0.9Sr0.1CoO3 with Ti3C2Tx 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. An active interfacial solar evaporation‐accelerated electrocatalytic heterostructure assembled from perovskite oxide and 2D Ti3C2Tx MXene on Ni foam and its implementation in the water‐splitting process are reported. The all‐in‐one integrated electrocatalyst demonstrates much higher activity for solar‐powered interfacial water evaporation and simultaneously shows remarkable electrocatalytic performance toward the oxygen evolution reaction and hydrogen evolution reaction.