Aromatic carboxylic acid derived bimetallic nickel/cobalt electrocatalysts for oxygen evolution reaction and hydrogen peroxide sensing applications

Development of suitable electrocatalysts is crucial for both oxygen evolution reaction (OER) and sensing applications. In this study, we present a solvothermal approach for producing a Nickel/Cobalt based Metal-Organic Framework (NiCo-MOF) employing various organic linkers including Benzene-1,4-dicarboxylic acid (BDC), 1,3,5-Benzene tricarboxylic acid (BTC), and 2-Amino Benzene-1,4-dicarboxylic acid (ABDC). The synthesized NiCo-MOF composites were characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray Diffraction (XRD),Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and X-ray photoelectron spectroscopy (XPS). NiCo-ABDC showed enhanced catalytic behavior for Oxygen Evolution Reaction (OER) with low onset over potential of 330 mV along with a modest tafel slope value of 88 mV/dec. Besides, NiCo-ABDC exhibited attractive stability for 1000 cycles and improved durability over 24 h which shows advanced kinetics over the noble metal catalysts and other carboxylic derived MOFs. As an electrochemical sensor, the NiCo-ABDF modified electrode shows a lower limit of detection (0.18 mM), highersensitivity (0.08 μA mM −1 ), and wider linear response (0–7 mM). This study provides clear evidence for the preparation of Ni-Co MOF composites without anchoring any polymer or carbon sources like graphene oxide (GO) and reduced graphene oxide (RGO), revealing its outstanding catalytic activity towards both OER and sensing applications.