Structure and phase regulation in Mo_xC (Α-MoC_1-x/Β-Mo₂C) to enhance hydrogen evolution

Non-precious metal-based efficient electrocatalysts with superior activity and stability for the hydrogen evolution reaction (HER) are useful in solving energy and environmental crises. Herein, monodisperse inverse opal-like Mo_xC (α-MoC_1-x/β-Mo₂C) nanospheres were synthesized via a facile strategy to adjust the intrinsic activity and maximize the exposed active sites. In particular, the Mo_xC-0.4 with the optimal composition of α-MoC_1-x/β-Mo₂C (0.56/0.44) demonstrated a superior HER performance in 0.5 M H₂SO₄ with a small Tafel slope of 48 mV dec⁻¹ and remarkable stability. Such prominent performance not only benefits from the inverse opal-like structure that provides more active sites for HER, but also should be ascribed to the strong synergistic effect between α-MoC_1-x and β-Mo₂C. Based on theoretical calculations, it is further verified that the synergistic effect of Mo_xC-0.4 is originated from the optimization of interaction with the H* induced by the heterostructure. Furthermore, this work will broaden our vision for highly efficient hydrogen production by bridging the microscopic structure with macroscopic catalytic performance.