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

Abstract

• NiCo(OH) 2 and NiCo-MOFs were developed sucessfully as an efficient electrocatalysts for both OER and H 2 O 2 sensor applications. • NiCo-ABDC has exhibited excellent OER action, and a lower tafel slope value when compared to other metal oxides and NiCo-MOFs. • Also, NiCo-ABDC composite has high sensitivity, a low detection limit, and a better selectivity for electro-reductive H 2 O 2 detection. 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.