Unveiling the synergy of MXene supported ZIF-8 hybrid catalyst for enhanced oxygen evolution reaction

Abstract

The oxygen evolution reaction (OER) is a critical process in sustainable energy technologies, but its sluggish kinetics necessitate efficient, non-precious metal catalysts. ZIF-8 has recently gained attention as a model electrocatalyst due to its porous structure, functional channels, and high Brunauer-Emett-Teller (BET) surface area. However, its poor conductivity and aggregation hinder its OER performance. MXene, a family of multifunctional 2D material with rich surface chemistry, shows great promise as a catalyst support material. This study presents the synthesis of ZIF-8 and MXene composites (MXene@ZIF-8) with varying ZIF-8 concentrations while maintaining a constant MXene mass to evaluate the supportive function of MXene in improving the OER performance of the composite. The optimized MXene@ZIF-8 (1:5) catalyst achieved superior performance, with a reduced overpotential (330 mV) and Tafel slope (149.79 mV/dec) compared to ZIF-8 (579 mV, 351.38 mV/dec) and MXene (613 mV, 400.02 mV/dec). It also exhibited exceptional durability, maintaining stability at 10 mA/cm² for 50 h in alkaline condition. The enhanced performance stems from its increased BET and electrochemically active surface areas. The incorporation of MXene introduces mesopores, increases pore volume, enhances hydrophilicity, and reduces charge transfer resistance, collectively facilitating efficient electrolyte diffusion and reactant accessibility. This study underscores MXene's potential as an efficient and cost-effective support material for advancing OER catalysts, facilitating the development of advanced sustainable energy solutions.