Nanocages Coupling with Carbides Quantum Dots for Efficient Hydrogen Evolution.

Zhao, Zejun; Wang, Weina; Xiao, Zheyu; Shi, Xiaodong; Li, Ruisong; Tian, Xinlong; Yang, Yong · Nano Lett · 2026

basic_science · Level V

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Abstract

An innovative strategy for synthesizing nitrogen-doped carbon nanocages embedded with ultrafine Mo<sub>2</sub>C and W<sub>2</sub>C quantum dots (Mo<sub>2</sub>C/W<sub>2</sub>C@NCNs) has been proposed through transition metal-assisted catalysis metal-organic framework (MOF) decomposition. During pyrolysis, Mo and W species derived from Mo(CO)<sub>6</sub> and W(CO)<sub>6</sub> facilitate the controllable thermal decomposition of the MOFs, forming a clear hollow structure. Meanwhile, the Mo and W substances transform into ultrafine Mo<sub>2</sub>C and W<sub>2</sub>C quantum dots and disperse in N-doped carbon matrix uniformly, which is conductive to boosting the catalytic activity and stability for HER. The optimized Mo<sub>2</sub>C/W<sub>2</sub>C@NCNs exhibits excellent HER performance, achieving low over potentials of 53.7 mV and 67.5 mV at 10 mA cm<sup>-2</sup> in acidic and alkaline media, respectively. The density functional theory calculations reveal that the Mo<sub>2</sub>C/W<sub>2</sub>C heterojunctions effectively modulate the <i>d</i>-band center position and optimize the Gibbs free energy for hydrogen adsorption, thereby enhancing the catalytic activity of the carbides.