The electrochemical methanol−hydrogen transformation as a significant technique for hydrogen generation is limited by a low Pt catalytic efficiency. Herein, the doping and interfacial support engineering of MoSe 2 nanosheets by NH 3 plasma confined in mesoporous hollow-carbon-spheressupported Pt nanoparticles (Pt/N-MoSe 2 @MHCS) were demonstrated as a novel platform for catalyzing methanol electrolysis. Experiments and density functional theory (DFT) calculations confirm that the band structure of the Pt species is downshifted to weaken the adsorption energy of CO ad /H ad , resulting in improved CO-poisoning resistance and accelerated electrocatalytic kinetics. As a result, Pt/ N-MoSe 2 @MHCS shows the highest current density of 99.2 mA cm −2 for methanol oxidation and a low overpotential of 26 mV@10 mA cm −2 for hydrogen evolution. The methanol-assisted water electrolyzer assembled by Pt/N-MoSe 2 @MHCS showed a low cell voltage of 1070 mV to reach 10 mA cm −2 . This work provides novel guidance for the design of reasonable noble-metal catalysts in methanol electrolysis for hydrogen production.