Cobalt carbonate hydroxide assisted formation of self-supported CoNi-based Metal–Organic framework nanostrips as efficient electrocatalysts for oxygen evolution reaction

The development of efficient and low-cost electrocatalysts is crucial for improving the efficiency of electrochemical oxygen evolution reaction (OER). Herein, self-supported CoNi-based metal-organic framework (MOF) nanostrips grown on Ni foam (NF) were synthesized with cobalt carbonate hydroxide (CoCH) nanoneedles as a sacrificial template and demonstrated to be highly efficient electrocatalysts for OER. In this approach, the CoCH nanoneedles play a key role in modulating the morphology of CoNi-MOF with reduced thickness and sizes through affording Co source and slowing down the leaching of Ni ions from the NF substrate. The resultant CoNi-MOF/CoCH/NF electrode possesses higher catalytically active surface area and smaller electrochemical impedance than CoCH template-free electrodes, which enable rapid mass transport and charge transfer during OER, thus showing enhanced electrocatalytic activity for OER. In alkaline media (1.0 M KOH), it needs a low overpotential of 251 mV to deliver a current density of 10 mA cm−2 and exhibits a small Tafel slope of 40.7 mV dec−1 as well as excellent durability. The developed approach may inspire further capability on constructing more promising catalysts for energy related applications.