Boosting alkaline hydrogen evolution through cobalt-regulated d-band center of metallic molybdenum and concurrent nitrogen-doping

Abstract

The development of highly active non-noble metal catalysts necessitates the enhancement of water adsorption and optimization of hydrogen intermediate (H*) adsorption/desorption kinetics during the alkaline hydrogen evolution reaction (HER). In this work, nitrogen-doped carbon nanotubes encapsulating MoCo bimetallic nanoparticles and anchored on carbon cloth (MoCo@CNT/CC) were synthesized via a combined solvothermal and annealing approach. Theoretical calculations reveal that Co doping introduces lattice tensile strain and facilitates electron transfer from Co to Mo, thereby enhancing water adsorption and optimizing the d-band center along with the Gibbs free energy for H* adsorption. Electrochemically, the optimized catalyst MoCo@CNT/CC-4 exhibits superior HER performance in 1 M KOH, requiring overpotentials of only 64 and 202 mV to achieve current densities of 10 and 300 mA cm⁻², respectively, and demonstrates exceptional durability over 200 h of continuous operation at 300 mA cm⁻². This study provides an effective strategy for designing high-performance, stable electrocatalysts for alkaline water splitting.