In situ formed VOOH nanosheet arrays anchored on a Ti3C2Tx MXene as a highly efficient and robust synergistic electrocatalyst for boosting water oxidation and reduction

Abstract

Developing low-cost and high-efficiency bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is pivotal for large-scale production of clean and sustainable hydrogen energy, but still remains challenging. In this work, a facile strategy to construct the VOOH/Ti₃C₂T_x MXene heterostructures is reported, benefiting from the optimized electronic structure and abundant heterogeneous interfaces that weakens the adsorption of oxygen-containing intermediates, as well as accelerating the dissociation of water molecules, thus facilitating the catalytic kinetics of the OER and HER. As expected, the VOOH/Ti₃C₂T_x MXene required overpotentials of 238 mV for the OER and 100 mV for the HER to reach a current density of 10 mA cm⁻². More importantly, by employing the VOOH/Ti₃C₂T_x MXene as both the anode and the cathode, a two-electrode alkaline electrolyzer delivers a current density of 10 mA cm⁻² at a low cell voltage of 1.579 V, which is superior to the commercial IrO₂‖Pt/C couple. This work opens up appealing opportunities for the rational design of MXene-based hybrid materials for efficient H₂ production and other energy-related applications.