Phase-engineering terraced structure of edge-rich α-Mo2C for efficient hydrogen evolution reaction

Molybdenum carbide (Mo2C) nanomaterials have become potential candidates for hydrogen evolution reaction (HER) electrocatalysts. However, the electrocatalytic performance of powdery Mo2C is restricted because of the insufficient active sites and structural integrity of the organic binders. In this study, alpha-Mo2C nanosheets with a terraced structure and numerous edges were directly synthesized on a Cu/Mo substrate as a self-supported electrode and used as an electrocatalyst for HER without binder and transfer processes. The terraced alpha-Mo2C nanosheets exposed numerous active sites with mixed poly-morphs (1T and 1H phases) and Bernal (AB) stacking. They showed long-term stability and satisfactory HER activity, with overpotentials of 226, 324, and 294 mV vs. RHE (at a current density of 10 mA.cm(-2)) and Tafel slopes of 74, 104, and 63 mV/dec in 1.0 M KOH, 1.0 M PBS, and 0.5 M H2SO4, respectively. Density functional theory calculations revealed that the 1T-1H interface and Bernal stacking at the terraced alpha-Mo2C enhance the electrocatalytic performance compared to 2D alpha-Mo2C. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

In this study, alpha-Mo2C nanosheets with a terraced structure and numerous edges were synthesized as self-supported electrodes for hydrogen evolution reaction (HER). They exhibited long-term stability and satisfactory HER activity.