Tuning the Reconstruction\nof Metal–Organic\nFrameworks during the Oxygen Evolution Reaction

Recently, there has been growing interest in the conversion\nof\nmetal–organic frameworks (MOFs) into metal-hydroxide catalysts\nfor alkaline oxygen evolution reactions (OERs). While studies have\nshown that the initial OER performance of MOF-derived intermediates\nsurpasses that of traditional metal-hydroxide catalysts, ongoing debates\npersist regarding these catalysts' durability and electrochemical\nstability. Moreover, the inevitable reorganization (aging) of MOF-derived\ncatalysts from disordered to ordered phases, particularly those primarily\ncomposed of nickel oxyhydroxides, remains a topic of discussion. To\naddress these issues, we propose a straightforward approach to mitigating\nMOF reconstruction and modulating aging in harsh alkaline environments\nby introducing additional organic carboxylate linkers into electrolytes.\nSpecifically, we focus on two examples: Ni-BPDC-MOFs and NiFe-BPDC-MOFs,\nof formula [M<sub>2</sub>(OH)<sub>2</sub>BPDC] (M: Ni and Fe; BPDC\n= 4,4′-biphenyldicarboxylate). Experimental results indicate\nthat alkaline electrolytes containing additional BPDC linkers exhibit\nenhanced OER activity and a prolonged electrochemical lifespan. Complemented\nby in situ Raman spectroscopy, our findings suggest that manipulating\nthe coordination equilibrium of the organic linker involved in Ni-MOF\nformation (linker assembly) and reconstruction (linker leaching) leads\nto the formation of more disordered nickel oxyhydroxide phases as\nthe active catalyst material, which shows enhanced OER performance.