In situ Engineering of Hollow Porous Mo C@C Nanoballs Derived From Giant Mo-Polydopamine Clusters as Highly...

Low-cost and highly effective catalysts are crucial to the electrocatalytic hydrogen evolution reaction (HER). Among non-noble catalysts, molybdenum carbides are promising candidates because of their high reserves, stability, low cost, and structural diversity. In this work, we report a simple method to fabricate a hollow porous Mo₂C@C nanoball through a hydrothermal preparation process of molybdenum precursors at high temperatures. Specifically, we have combined interfacial polymerization and the chelation effect to synthesize the Mo-polydopamine (Mo-PDA) precursor. As a result, Mo₂C@C-3 only requires an ultralow Tafel slope (~55 mV dec^-1) and low overpotential (η₅₀ ≈ 167 mV) in a 0.5 M H₂SO₄ solution with long-term cycling stability. Besides, it also exhibits outstanding activity and stability under extensive HER testing in alkaline media. This study is promising for the development of advanced molybdenum carbide electrocatalysts toward electrochemical applications.