High-efficiency electrocatalytic hydrogen evolution in NiCo-MoC tandem nanoreactors with bimetallic modulation and crystal plane synergy.

MoC, with an electronic structure closely resembling that of Pt, holds significant promise as a catalyst for nonprecious metal-based electrocatalytic hydrogen evolution reactions (HER). This study presents the design and synthesis of Ni and Co bimetallic-doped MoC (NiCo-MoC) tandem nanoreactors, engineered by leveraging the concept of a high-gain transistor cascade amplifier. In NiCo-MoC material, each monomer layer on MoC rod functions as an individual electrocatalytic nanoreactor, with the rod supporting a tandem configuration of these units. The combined modulation of Ni and Co at NiCo-MoC interface increases the electron cloud density around Mo and shifts the d-band center negatively, effectively reducing Mo-H* binding energy. The synergy between NiCo-MoC (101) and (002) crystal planes facilitates both water dissociation and H* desorption from Mo sites. This tandem configuration of multicatalytic units achieves enhanced hydrogen evolution, demonstrated by the low overpotential at 10 mA·cm (η) values of 129 mV and 180 mV and Tafel slopes of 84 mV·dec and 85 mV·dec in 1 M KOH and 0.5 M HSO, respectively. Through bimetallic modulation, crystal plane synergy, and tandem structuring, this work advances a novel approach to optimizing HER kinetics, presenting a valuable strategy for developing highly efficient, nonprecious metal-based electrocatalysts.