The overall water splitting is severely limited by the sluggish oxygen evolution reaction (OER), which further restricts the large-scale production of hydrogen for sustainable energy. These transition metal-based (oxy)hydroxides (TM(O)OH) are recognized as the most efficient non-noble electrocatalysts for OER, but the rational design and fabrication of TM(O)OH species remain a big challenge. Here we have synthesized a porous metal-organic framework (MOF, CoHKUST-1), and the rapid degradation of this MOF itself in alkaline solution is intrinsically stemmed from the metastable nature of the Co–O coordination bonds in the Co-based paddle wheel. By simply applying an electric potential, these synthesized Co-MOFs can be decomposed into the 2-dimensional nanosheet structure mainly consisting Co(OH)₂ and CoOOH. The resulting CoO_xH_y nanosheets exhibit excellent OER performance to reach an overpotential of only 344 mV at 10 mA cm⁻², and its Tafel slope is calculated to be 66.4 mV dec⁻¹ indicating the fast reaction kinetics. The structural and morphological evolution under electrolysis is further proposed and evidenced by relevant physicochemical characterizations and theoretical calculations. The demonstrated work proves a feasible strategy for electrochemical design and fabrication of 2-dimensional TM(O)OH nanosheets for efficient water oxidation, which can be further applied in the future energy applications.

缓慢的氧气析出反应（OER）严重限制了总的水分解，这进一步限制了大规模生产可持续能源的氢。这些过渡金属基（羟基）氢氧化物（TM（O）OH）被认为是OER的最有效的非贵金属电催化剂，但是TM（O）OH种类的合理设计和制造仍然是一个很大的挑战。在这里，我们合成了一个多孔的金属-有机骨架（MOF，CoHKUST-1），并且该MOF本身在碱性溶液中的快速降解本质上是基于Co基桨轮中Co-O配位键的亚稳性质。 。通过简单地施加电势，这些合成的Co-MOF可以分解为主要由Co（OH）₂组成的二维纳米片结构和CoOOH。所得的CoO _x H _y纳米片表现出优异的OER性能，在10 mA cm ^-2时仅达到344 mV的过电势，其Tafel斜率经计算为66.4 mV dec ^-1，指示了快速的反应动力学。进一步提出了电解条件下的结构和形态演化，并通过相关的理化特征和理论计算得到证明。证明的工作证明了用于高效水氧化的二维TM（O）OH纳米片电化学设计和制造的可行策略，可以进一步应用于未来的能源应用中。