Two-dimensional metal-organic frameworks (MOFs) are promising earth-abundant electrocatalysts, especially for the key process of oxygen evolution reaction (OER), but challenges remain in the lack of effective synthesis and stabilization strategies. Here we first develop a general self-dissociation-assembly (SDA) strategy for in situ synthesis of well-defined ultrathin CoNi-MOF nanosheet arrays (CoNi-MOFNA) as highly active OER electrode. Remarkably, CoNi-MOFNA exhibit excellent OER activity and long-term stability, which deliver the current density of 10 mA cm^-2 at a low overpotential of 215 mV with negligible decay even after 300 h continuous electrolysis. The mass activity of CoNi-MOFNA is 14-times higher than commercial RuO₂. In addition, the systematic electrochemistry and time-dependent XAS spectroscopy studies convincingly identify the OER active sites of coordinatively unsaturated metal nodes and uncover the structure evolution of CoNi-MOFNA. More importantly, we have demonstrated the universality of this significant SDA strategy for controllably fabricating other types of ultrathin MOF nanosheet arrays uniformly on diverse metal substrates.

二维金属有机框架（MOF）是有前途的地球上富裕的电催化剂，尤其是对于氧释放反应（OER）的关键过程而言，但仍然缺乏有效的合成和稳定策略。在这里，我们首先开发一种通用的自解离组装（SDA）策略，用于原位合成明确定义的超薄CoNi-MOF纳米片阵列（CoNi-MOFNA）作为高活性OER电极。值得注意的是，CoNi-MOFNA具有出色的OER活性和长期稳定性，即使在连续电解300小时后，在215 mV的低过电势下仍可提供10 mA cm ^-2的电流密度。CoNi-MOFNA的质量活性是商业RuO _2的14倍。此外，系统的电化学和随时间变化的XAS光谱学研究令人信服地确定了不饱和配位金属节点的OER活性位点，并揭示了CoNi-MOFNA的结构演变。更重要的是，我们已经证明了这种重要的SDA策略的普遍性，该策略可控地在各种金属基材上均匀地制造其他类型的超薄MOF纳米片阵列。