Dispersing catalytically active metals as single atoms on supports offer an efficient pathway to minimize amount of precious metals. Although platinum (Pt) is highly active for HER, it is highly desirable to find ways to improve the HER performance and also keeping them stable during catalytic reactions while minimizing the Pt loading. Herein, we report a cathode polarization technique to disperse isolated single Pt atoms on β-Mo₂C as a catalyst for HER. The isolated Pt atoms partially occupy Mo sites in Mo₂C lattice by forming Pt-Mo shells, which maximize the utilization ratio of platinum noble metals. The single atoms catalyst Mo₂C/CFP-Act even exhibited 1.9 and 1.1 times higher current density (@ potential of 0.4 V vs. RHE) than that of Pt NPs catalysts (Mo₂C/CFP-Pt) after mass normalization in both acidic and alkali solution. Furthermore, DFT calculations demonstrate that Mo₂C/CFP-Act exhibits favorable ΔG_H* for the adsorption and desorption of hydrogen. The high HER activity of the Mo₂C/CFP-Act catalyst is related to the Mo-Pt center located in Mo₂C matrix, where the electronic structure of the Mo-Pt centers more efficient in donating electron to the σ* antiorbital of the H₃O⁺ molecule. This study sheds new light on the HER catalysis mechanism of isolated metal atoms based on fundamental understanding in molecular governing factors.

将催化活性金属作为单原子分散在载体上，提供了一条有效的途径，可将贵金属的量降至最低。尽管铂（Pt）对HER具有很高的活性，但非常需要找到提高HER性能并在催化反应过程中保持稳定的同时最小化Pt负载的方法。此，我们报告的阴极极化技术，以分散在β-沫分离单个的Pt原子₂ C作为用于HER的催化剂。通过形成Pt-Mo壳，孤立的Pt原子部分地占据了Mo ₂ C晶格中的Mo位置，从而使铂贵金属的利用率最大化。单原子催化剂Mo ₂在酸性和碱性溶液中进行质量归一化后，C / CFP-Act甚至表现出比Pt NPs催化剂（Mo ₂ C / CFP-Pt）高1.9倍和1.1倍的电流密度（相对于RHE的电势为0.4 V）。此外，DFT计算表明，Mo ₂ C / CFP-Act对于氢的吸附和解吸表现出有利的ΔGH _*。Mo ₂ C / CFP-Act催化剂的高HER活性与位于Mo ₂ C基质中的Mo-Pt中心有关，在该中心，Mo-Pt的电子结构更有效地向电子的σ*反轨道供体H ₃ O ⁺分子。这项研究基于对分子控制因素的基本理解，为孤立金属原子的HER催化机理提供了新的思路。