Fabrication of NiFe-MOF/cobalt carbonate hydroxide hydrate heterostructure for a high-performance electrocatalyst of oxygen evolution reaction

Metal-organic frameworks (MOFs) have been widely investigated as electrocatalysts for the oxygen evolution reaction (OER). However, their catalytic performance needs to be further improved. Herein, a multi-pronged approach combining multi-metallic MOFs, 2D ultrathin structures and MOF hybridization was attempted. Specifically, the nanocomposite of lamellar NiFe-BTC and nanowire-like cobalt carbonate hydroxide hydrate (CCHH) was prepared on nickel foam (NF) by a two-step method. The as-prepared NiFe-BTC/CCHH/NF nanocomposite displayed excellent OER performance with an overpotential of 270 mV at a current density of 50 mA cm−2 and good stability in 1.0 M KOH. To construct an overall water splitting electrolytic cell, the phosphorization product of CCHH/NF (P-CCHH/NF) with high catalytic activity for hydrogen evolution reaction (HER) was used as the cathode. The water splitting electrolytic cell with NiFe-BTC/CCHH/NF as anode and P-CCHH/NF as cathode was highly efficient and stable, which only needed a voltage of 1.55 V to reach a current density of 10 mA cm−2. This multi-pronged approach is expected to inspire other researchers to design high-performance OER catalysts.