Metal-organic framework-derived CoNi-embedded carbon nanocages as efficient electrocatalysts for oxygen evolution reaction

The major challenge of electrocatalytic water splitting for hydrogen production is the sluggish kinetics of oxygen evolution reaction (OER). Herein, we report a facile synthesis of CoNi alloy embedded carbon nanocages (CoNi-C) through one-step annealing treatment of bimetallic organic frameworks as the precursors for application as efficient and economical electrocatalysts for OER. As a result, the optimized CoNi-C-200 sample with a Co/Ni atomic ratio of 9:1 exhibits a lower overpotential of 408 mV at a current density of 10 mA cm−2 and a smaller Tafel slope of 83 mV dec−1 compared to as-prepared CoNi-C-100 (410 mV, 93 mV dec−1), CoNi-C-400 (420 mV, 94 mV dec−1), and Co-C (447 mV, 97 mV dec−1). Moreover, it shows an excellent long-term stability during 5000 CV sweeps. Such improved performance can be attributed to the unique morphology and the synergistic effects of CoNi alloy nanoparticles and conductive carbon matrix in the composite.