Stable Hierarchical Bimetal–Organic Nanostructures as High-Performance Electrocatalysts for the Oxygen Evolution Reaction

Wei Zhou + , Dan-Dan Huang + , Ya-Pan Wu, Jun Zhao, Tao Wu, Jian Zhang, Dong-Sheng Li,* Chenghua Sun,* Pingyun Feng, and Xianhui Bu*

       Abstract: The integration of heterometallic units and nanostructures into metal–organic frameworks (MOFs) used for the oxygen evolution reaction (OER) can enhance the electro-catalytic performance and help elucidate underlying mechanisms. We have synthesized a series of stable MOFs (CTGU10a1–d1) based on trinuclear metal carboxylate clusters and a hexadentate carboxylate ligand with a (6,6)-connected nia net. We also present a strategy to synthesize hierarchical bimetallic MOF nanostructures (CTGU-10a2–d2). Among these, CTGU-10c2 is the best material for the OER, with an overpotential of 240 mVat a current density of 10 mAcm -2 and a Tafel slope of 58 mVdec -1 . This is superior to RuO 2 and confirms CTGU-10c2 as one of the few known high-performing pure-phase MOF-OER electrocatalysts. Notably, bimetallic CTGU-10b2 and c2 show an improved OER activity over monometallic CTGU-10a2 and d2. Both DFTand experiments show that the remarkable OER performance of CTGU-10c2 is due to the presence of unsaturated metal sites, a hierarchical nanobelt architecture, and the Ni–Co coupling effect.