Mo₂C and WC are widely considered as promising electrocatalysts for hydrogen evolution reaction (HER) owing to their Pt-like electronic features. Herein, dual-phased Mo₂C-WC nanocrystals, densely and uniformly confined in ultrathin carbon nanosheet assemblies (abbreviated as Mo₂C-WC/NCAs), which are possible candidates for high-performance HER electrocatalysts, are fabricated through the in-situ pyrolysis of polymers containing Mo and W. When evaluated as HER electrocatalysts, Mo₂C-WC/NCAs requires a small overpotential of ∼126 mV to drive a current density of 10 mA cm^-2, and low Tafel slopes of 72 mV dec^-1 and 59 mV dec^-1 in acidic and alkaline media, respectively. In addition, the Mo₂C-WC/NCAs exhibit robust catalytic stability up to 36 h. The introduction of dual-phased carbide heterostructures can modify the electronic structure and simultaneously facilitate the charge transfer of the catalysts, consistent with the density functional theory (DFT) calculations. This work highlights the in-situ construction of multi-phased hetero-metal carbide heterostructures for high-performance electrocatalysis.

Mo ₂ C和WC由于具有类似Pt的电子特征，因此被广泛认为是用于氢释放反应（HER）的电催化剂。在此，通过以下方法制备了双相Mo ₂ C-WC纳米晶体，其密实且均匀地限制在超薄碳纳米片组件（缩写为Mo ₂ C-WC / NCA）中，它们可能是高性能HER电催化剂的候选材料。含有Mo和W的聚合物的原位热解。当作为HER电催化剂进行评估时，Mo ₂ C-WC / NCAs需要约126 mV的小过电位来驱动10 mA cm ^-2的电流密度和低的Tafel斜率（降低了72 mV）^-1和59 mV dec ^-1分别在酸性和碱性介质中。另外，Mo ₂ C-WC / NCA表现出长达36小时的强大催化稳定性。与密度泛函理论（DFT）计算相一致，引入双相碳化物异质结构可以修饰电子结构，同时促进催化剂的电荷转移。这项工作强调了用于高性能电催化的多相杂金属碳化物异质结构的原位构建。