Architecting the High-Entropy Oxides on 2D MXene Nanosheets by Rapid Microwave-Heating Strategy with Robust Photoelectrochemical Oxygen Evolution Performance.

High-entropy oxides (HEO) have recently concerned interest as the most promising electrocatalytic materials for oxygen evolution reactions (OER). In this work, a new strategy to the synthesis of HEO nanostructures on Ti 3 C 2 T x MXene via rapid microwave heating and subsequent calcination at a low temperature is reported. Furthermore, the influence of HEO loading on Ti 3 C 2 T x MXene is investigated toward OER performance with and without visible-light illumination in an alkaline medium. The obtained HEO/Ti 3 C 2 T x -0.5 hybrid exhibited an outstanding photoelectrochemical OER ability with a low overpotential of 331 mV at 10 mA cm -2 and a small Tafel slope of 71 mV dec -1 , which exceeded that of a commercial IrO 2 catalyst (340 mV at 10 mA cm -2 ). In particular, the fabricated water electrolyzer with the HEO/Ti 3 C 2 T x -0.5 hybrid as anode required a less potential of 1.62 V at 10 mA cm -2 under visible-light illumination. Owing to the strong synergistic interaction between the HEO and Ti 3 C 2 T x MXene, the HEO/Ti 3 C 2 T x hybrid has a great electrochemical surface area, many metal active sites, high conductivity, and fast reaction kinetics, resulting in an excellent OER performance. This study offers an efficient strategy for synthesizing HEO-based materials with high OER performance to produce high-value hydrogen fuel.