Nonprecious transition metal phosphides (TMPs) have emerged as robust electrocalysts for the hydrogen evolution reaction (HER). However, the TMPs suffer from low activity for water dissociation, which greatly limits the efficiency for alkaline HER. Here, a facile yet robust strategy is reported to boost the HER of metal phosphides by coating defective TiO₂ overlayers. The oxygen vacancies (O_v) on defective TiO₂ overlayers are found to possess high activity for adsorption and dissociation of water, thereby significantly promoting the initial Volmer step of HER to generate the reactive hydrogen atoms. Moreover, the porous (Co, Ni)₂P (i.e., Co₂P and Ni₂P) nanosheets provide enough active sites for adsorption and recombination of reactive hydrogen atoms to produce hydrogen gas. The catalytic synergy of (Co, Ni)₂P and O_v coupled with the hierarchically porous structure renders the porous (Co, Ni)₂P@0.1TiO₂ nanosheet arrays excellent electrocatalysts for HER, showing a small overpotential (92 mV) to yield a current density of 10 mA cm⁻², a small Tafel slope (49 mV dec⁻¹), and an outstanding stability. This work demonstrates a surface decoration route for enhancing the activity of nonprecious metal‐based electrocatalysts for HER.

中文翻译：

---

通过涂覆有缺陷的TiO2覆盖层促进多孔金属磷酸盐纳米片的电化学氢逸出

非贵金属的过渡金属磷化物（TMPs）已成为氢析出反应（HER）的稳健电催化剂。但是，TMP的水解离活性低，这极大地限制了碱性HER的效率。在此，据报道，通过涂覆有缺陷的TiO ₂覆盖层来提高金属磷化物的HER的简便而稳健的策略。发现有缺陷的TiO ₂覆盖层上的氧空位（O _v）具有高的吸附和解离水的活性，从而显着促进了HER的Volmer初始步骤生成反应性氢原子。而且，多孔的（Co，Ni）₂ P（即，Co ₂ P和Ni ₂P）纳米片提供足够的活性位点，以吸附和重组反应性氢原子以产生氢气。（Co，Ni）₂ P和O _v的催化协同作用以及分层多孔结构使多孔（Co，Ni）₂ P@0.1TiO ₂纳米片阵列成为HER的优良电催化剂，显示出较小的超电势（92 mV）。产生10 mA cm ^-2的电流密度，小的Tafel斜率（49 mV dec ^-1）和出色的稳定性。这项工作展示了一种表面装饰途径，可以增强用于HER的非贵金属基电催化剂的活性。