Modulating Electronic State and <i>d</i>-Band Center of Mo Atoms for High-Efficient Hydrogen Evolution
Guangyan Tian, Wenqian Qu, Kefeng Zhang, Jinfang Wu, Weisen Huang, Ronghui Gu, Gao‐Feng Han, Wenbo Wang
Abstract
Electrocatalysts play a crucial role in efficient hydrogen production through water splitting, and there is significant interest in enhancing their performance via microscopic regulation. In this study, we introduce for the first time a novel series of Mo 2 C/MoO 2 /C electrocatalysts enriched with heterojunctions, synthesized using sustainable carbon precursors such as vegetable oil. The incorporation of heterojunctions within these catalysts fine-tunes the electronic structure of Mo atoms, shifting the d -band center to significantly improve catalytic efficiency. The developed Mo 2 C/MoO 2 /C electrocatalysts exhibit low overpotentials of 104 mV in 1 M KOH and 141 mV in 0.5 M H 2 SO 4 electrolytes at a current density of 10 mA·cm –2, with Tafel slopes of 67.30 mV·dec –1 and 71.21 mV·dec –1, respectively. These catalysts also show exceptional stability, maintaining their activity for over 30 h under both acidic and alkaline conditions. Density functional theory (DFT) calculations provide insights into the mechanism behind this enhanced performance. They reveal that the adjusted electronic states of Mo atoms and the shifted d -band center optimize the adsorption and desorption dynamics of hydrogen intermediates (H*), thereby significantly boosting the hydrogen evolution reaction (HER) activity. This strategy is universal, as an electrocatalyst prepared using carbon source waste cooking oil also achieves comparable overpotentials of 106 mV in 1 M KOH and 136 mV in 0.5 M H 2 SO 4 at the same current density. It also delivers superior double-layer capacitance values of 112.05 mF·cm –2 and 77.25 mF·cm –2 in the respective electrolyte solutions. This highlights the significant potential of natural carbon precursors for advanced electrocatalyst design.