Molybdenum disulphide (MoS₂) is proven to be a promising catalyst for hydrogen evolution reaction (HER), but the HER performance of reported MoS₂-based catalysts is still limited by its poor conductivity and low density of active sites. Herein, a Pt-doped MoS₂ (Pt@MoS₂) catalyst is synthesized by a potential-cycling method, which introduces the Pt dopant into the MoS₂ lattice and achieves partial 2H to 1T phase conversion of MoS₂ simultaneously. Benefitting from the optimized geometric and electronic structure of MoS₂, the Pt@MoS₂ exhibits a low overpotential of 88.43 mV at 10 mA cm⁻², which is decreased by two-thirds as compared to that of the pristine MoS₂. A comprehensive study reveals the position and the contribution of Pt atom in electronic structure modulation of MoS₂. Theoretical calculations further reveal that the S atom adjacent to the Pt in MoS₂ acts as the most active site for HER, and possesses a small hydrogen adsorption free energy ($∆G_{H*}$) of ~ 0.04 eV, similar to the benchmark Pt catalyst. This study opens up a new avenue for designing MoS₂ and other transition metal dichalcogenide-based electrocatalysts with enhanced HER performance, as well as providing in-depth understanding on the HER mechanism in external metal-activated MoS₂ catalyst.

二硫化钼（MoS ₂）被证明是有前途的氢释放反应（HER）催化剂，但是已报道的基于MoS ₂的催化剂的HER性能仍然受到其导电性差和活性位点密度低的限制。在此，在Pt掺杂的MoS ₂（铂@的MoS ₂）催化剂通过电位循环方法，该方法引入了在Pt掺杂剂注入到所述MOS合成₂晶格并实现局部2H莫斯的1T相位转换₂同时进行。受益于MoS ₂的优化几何和电子结构，Pt @ MoS ₂在10 mA cm ^-2时显示出88.43 mV的低过电势与原始MoS ₂相比减少了三分之二。全面的研究揭示了Pt原子在MoS ₂电子结构调制中的地位和贡献。理论计算进一步表明，MoS _2中与Pt相邻的S原子是HER的最活跃位点，并具有较小的氢吸附自由能（$\Delta G_{H*}$）〜0.04 eV，类似于基准Pt催化剂。这项研究为设计具有增强的HER性能的MoS ₂和其他过渡金属二卤化钴基电催化剂开辟了一条新途径，并提供了对外部金属活化的MoS ₂催化剂中HER机理的深入了解。