Fabrication of Mo─N Modified Mesoporous Carbon-Coated Carbon Nanotubes via Dual-Template Strategy for Enhanced Electrocatalytic Hydrogen Evolution.

The development of non-noble metal catalysts with high activity and stability for the electrocatalytic hydrogen evolution reaction (HER) remains highly important. This study addresses the challenge of simultaneously achieving high activity and durability by proposing a hard-soft template synergistic strategy to construct mesoporous carbon-coated carbon nanotube heterostructures. Using 3-aminophenol as the carbon and nitrogen source and phosphomolybdic acid as the metal precursor, Mo─N modified mesoporous carbon layers were in situ grown on carbon nanotube surfaces, yielding CNT@Mo3O8/NC composites. The optimized catalyst, CNT@Mo3O8/NC-0.1-2Mo, exhibited favorable HER activity in both acidic and alkaline electrolytes, requiring overpotentials of 143 and 169 mV at 10 mA cm-2, with Tafel slopes of 100.2 and 92.1 mV dec-1, respectively. It demonstrated excellent stability, with less than 5% degradation after 1000 CV cycles and 15-20 h of chronoamperometry. The enhanced performance is attributed to Mo─N─C active sites, improved mass transfer via the mesoporous structure, suppressed agglomeration through strong metal-support interactions, and enhanced electron transport via the CNT conductive network. This work provides a feasible approach for transition metal/carbon-based composite electrocatalysts.