All-pH Hydrogen Evolution by Heterophase Molybdenum Carbides Prepared via Mechanochemical Synthesis

As non-precious-metal catalysts for the hydrogen evolution reaction (HER), molybdenum carbides have attracted extensive attention in recent years. Molybdenum carbides usually require high synthesis temperatures (>700 °C), which leads to a high cost. In this study, we report a controllable synthesis of heterophase molybdenum carbides (MoC/Mo₂C) using a simple ball milling method without external thermal input. The as-obtained MoC/Mo₂C catalysts exhibit excellent HER electrocatalytic activity and durability at all pH conditions in comparison with MoC or Mo₂C alone. The interface of MoC/Mo₂C formed in situ is the key factor in improving the electrocatalytic activity. This fabrication method is cheap and effective in generating heterophase interfaces, which can be employed in many other fields where interface engineering is needed.