Rapid synthesis of a CuZn-MOF via controlled electrodeposition: manifesting enhanced overall electrocatalytic water splitting

Abstract

The immense potential of metal–organic frameworks (MOFs) in electrocatalytic applications has resulted in an upsurge of interest in these materials. Herein, we demonstrate the rapid electrodeposition of a bimetallic MOF (CuZn-BTC-250) on a nickel foam (NF) substrate under controlled electrochemical reaction conditions using BTC as a linker. The CuZn-BTC-250 electrode exhibits electrocatalytic activity for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) which is even better than that of commercially available RuO₂ and Pt/C at higher current densities (above 250 mA cm⁻²). During overall water splitting, the catalyst displays an onset potential of 1.37 V, whereas commercially available RuO₂‖Pt/C exhibits 1.38 V in alkaline solutions. The catalyst is highly stable and does not show any significant change in the current density even after 120 hours of continuous operation. From the density functional theory calculation, it is observed that the ‘Cu’ site in the MOF is more active for the OER and HER. Herein, the work also emphasizes the importance of time-controlled electrodeposition, which can enhance the performance of the electrode.