Phosphorized MXene-Phase Molybdenum Carbide as an Earth-Abundant Hydrogen Evolution Electrocatalyst

MXenes with good conductivity and hydrophilicity are a new family of potential electrocatalysts (e.g., for hydrogen evolution). However, pristine MXenes usually show unsatisfactory catalytic activity compared with traditional platinum group metal electrocatalysts. We introduce both phosphorus and oxygen into Mo2CTx MXenes through a simple phosphorization course. The phosphorized Mo2CTx MXenes exhibit significantly improved electrocatalytic performance toward hydrogen evolution reaction compared with pristine Mo2CTx MXenes, with a dramatic decrease in overpotential (more than 100 mV at 10 mA cm–2). Theoretical computation suggests that P and O doped Mo2CTx MXenes possess a metallic band structure and an optimal hydrogen adsorption, which lead to improved conductivity and electrocatalytic kinetics, respectively. This work not only advances the understanding of property-tuning of the latest two-dimensional MXene materials but also paves the way for the development of MXene-based materials that can be applied in the field of energy conversion and storage.