Surface reconstruction of transition metal based electrocatalysts is a highly efficient strategy for water splitting, which is usually observed in oxygen evolution reaction. However, most of them are not designed subjectively and it brings great difficulties to developing and understanding the catalysts with well-defined structure after the reconstruction. We demonstrate here the design and synthesis of ZnCo phosphate that allows a two-step treatment for controllable surface reconstruction with Co²⁺ or Co³⁺ (oxy)hydroxide. The surface reconstruction continuously boosts the HER performance in alkaline electrolytes. More aided experiments are designed to disclose that the depletion of PO₄³⁻ in concentrated alkali and Zn²⁺ in following electrochemical etching serve as the key to trigger the reconstruction for Co²⁺-rich hydroxide and Co³⁺-rich oxyhydroxide, respectively. The reconstructed catalyst can work on hydrogen evolution for more than 50 h at high current density (1200 mA cm⁻²). Density functional theory simulations uncover the atomic-level understanding on the boosted catalytic performance. The energetically favorable electronic structure roots in the interfacial interaction and charge transfer. This work supplies valuable insights for the reconstruction chemistry and paves a new way to rational design heterogeneous catalysts associated with surface reconstruction in alkaline water electrolysers, and can cope with large-scale industrial water decomposition.

过渡金属基电催化剂的表面重建是一种高效的水分解策略，通常在析氧反应中观察到。然而，它们中的大多数都不是主观设计的，这给重建后具有明确结构的催化剂的开发和理解带来了很大的困难。我们在这里展示了 ZnCo 磷酸盐的设计和合成，它允许使用 Co ²⁺或 Co ³⁺（羟基）氢氧化物进行可控表面重建的两步处理。表面重建不断提高碱性电解质中的 HER 性能。设计了更多辅助实验以揭示浓碱和 Zn ²⁺中 PO ₄ ^3-的消耗在随后的电化学蚀刻中，分别作为触发富Co ²⁺氢氧化物和富Co ³⁺羟基氧化物重构的关键。重建的催化剂可以在高电流密度（1200 mA cm ^-2）下析氢超过 50 小时。密度泛函理论模拟揭示了对提高催化性能的原子级理解。能量有利的电子结构源于界面相互作用和电荷转移。这项工作为重构化学提供了有价值的见解，并为合理设计与碱性水电解槽表面重构相关的多相催化剂铺平了道路，并且可以应对大规模工业水分解。