Calixarene Intercalated NiCo Layered Double Hydroxide\nfor Enhanced Oxygen Evolution Catalysis

Abstract

Water\nsplitting provides a promising, sustainable way to resolve\nproblems arising due to depleting fossil fuels. The success needs\ndevelopment of low-cost and high-performance electrode materials.\nThe oxygen evolution reaction (OER) is a crucial reaction in water\nsplitting. The combined Ni and Co oxide developed nanostructures\nhaving a small overpotential and fast kinetics of OER. They have\ndrawn considerable attention, because of their theoretically high\nefficiency, high abundance, low cost, and environmental benignity\nin comparison with precious metal oxides, such as RuO₂ and\nIrO₂. However, the desired efficiency needs the developments\nof enhanced specific active area and conductivity. In the present\ncommunication, we address these issues. Specifically, exfoliation\nof layer double hydroxide (LDH) is applied to enhance the active surface\narea. The study reveals that intercalation by calixarene in NiCo LDH\naffords a multifunctional interlayer to deliver a large active surface\narea and fast electron transport toward the carbon nano-onion (CNO)\nsupport. It favorably lowers the overpotentials in OER (290 mV) and\n attains Tafel slope of 31 mV/decade. Enhanced conductivity\nis achieved using CNO as a support for the calixarene intercalated\nNiCo LDH. These developments offer a synergistic effect in achieving\nsuperior electrocatalytic activity for OER. This work gives insight\ninto designing binder-free electrodes in alkaline media with good\nstability for advanced OER activity.