Transition metal phosphides (TMPs) have been proven to act as highly active catalysts for the hydrogen evolution reaction (HER). Recently, single-phase ternary NiCoP electrocatalysts have been shown through experiments to display remarkable catalytic activity for the HER during water splitting. But, the inherent mechanism is not well understood. Herein, the HER activity of NiCoP with low-Miller-index facets, including (111), (100), (001)-NiP-t, and (001)-CoP-t, was systematically investigated using periodic density functional theory (DFT). The calculated Gibbs free energy of hydrogen adsorption (Δ G _(H) ) values reveal that all calculated facets have good catalytic activity for the HER. The (111) facet with the lowest surface energy in a vacuum has optimal Δ G _(H) values close-to-zero for a range of hydrogen coverage. Ab initio thermodynamic analysis of hydrogen coverage was conducted to obtain the stabilities of surfaces, which follow the trend: (111) > (001)-CoP-t > (100) > (001)-NiP-t at 1 atm H _(2) and 298 K. We hope that this work can shed new light on further understanding the HER in relation to NiCoP and can give guidance for the design and synthesis of transition bimetal phosphide-based catalysts.
展开▼
机译：过渡金属磷化物（TMP）已被证明可作为氢释放反应（HER）的高活性催化剂。最近，通过实验显示单相三元NiCoP电催化剂在水分解过程中显示出对HER的显着催化活性。但是，其内在机制还没有被很好地理解。本文使用周期密度泛函理论系统地研究了具有低米勒指数刻面的NiCoP的HER活性，其中包括（111），（100），（001）-NiP-t和（001）-CoP-t）（ DFT）。所计算的氢吸附的吉布斯自由能（ΔG _（H））值表明，所有所计算的面均具有良好的HER催化活性。对于一定范围的氢覆盖范围，在真空中具有最低表面能的（111）晶面的最佳ΔG _（H）值接近于零。从头开始进行氢覆盖的热力学分析以获得表面的稳定性，其遵循以下趋势：（111）>（001）-CoP-t>（100）>（001）-NiP-t在1 atm H _（ 2）和298K。我们希望这项工作可以为进一步了解与NiCoP有关的HER提供新的思路，并可以为过渡双金属磷化物基催化剂的设计和合成提供指导。
展开▼
