Interfacial engineering of N, S-doped Mo2C-Mo/C heterogeneous nanorods for enhanced alkaline hydrogen evolution

[Display omitted] •Composition of Mo-based nanoparticles embedded in carbon matrix is delicately controlled by initiator amount/calcination temperature.•N, S-doping and rich oxygen vacancies provide numerous catalytic defects.•Mo2C-Mo/C heterogeneous nanorods with abundant active heterointerfaces display remarkable HER activity and long-term durability. Interfacial engineering of cost-effective non-noble materials is attractive for synthesizing advanced electrocatalysts toward hydrogen evolution reaction (HER). Herein, we prepare N, S-doped Mo2C-Mo/C heterogeneous nanorods (NSMB-1.25) with abundant active heterointerfaces and defect sites via in situ polymerization and carburization strategy. The polyaniline-derived heteroatom-doped carbon acts not only as a matrix but also as a carbon source for Mo2C formation. The phase transition of Mo2C-Mo heterostructure is accurately regulated by delicately varying the dosage of the polymerization initiator and calcine temperature. The synergistic effects of Mo2C, metallic Mo and N, S doping carbon significantly enhance the HER activity and durability of nanorods. Benefiting from the plentiful active sites of the Mo2C-Mo heterointerfaces, fast charge and mass transfer channels, heteroatomic doping and large surface area, the as-prepared NSMB-1.25 nanorods deliver only 118 mV overpotential at 10 mA cm−2 current density, small Tafel slopes of 74 mV dec-1, high exchange current density of 25.84 × 10-2 mA cm−2 and excellent stability in 1.0 M KOH solution. This work may support a feasible strategy for reasonably designing highly active heterogeneous interfaces to achieve efficient energy conversion and storage.