Electrodeposited CoNi-LDH nanosheets supported on halloysite nanotubes as a robust and highly efficient electrocatalyst for water oxidation

Abstract

This article presents the development of efficient catalysts for electrocatalytic water oxidation by synthesizing CoNi-LDH/HNT (cobalt–nickel layered double hydroxide/halloysite nanotube) binary composites. Four novel CoNi-LDH/HNT nanocomposites were fabricated on nickel foam substrates by electrodepositing CoNi-LDH nanostructures onto HNT-modified nickel foam. The electrocatalytic activities of these nanocomposites were evaluated in the alkaline oxygen evolution reaction (OER). Incorporating HNTs as a support material significantly enhanced the performance of pristine CoNi-LDH in the OER. Through the manipulation of the Co/Ni molar ratio in the LDH, a nanocomposite with optimal performance was achieved (denoted as CoNi/H-2). This nanocomposite demonstrated superior electrocatalytic activity in the alkaline OER. Specifically, it exhibited an overpotential of 183 mV (at 10 mA cm⁻²) and a Tafel slope of 68.2 mV decade⁻¹. CoNi/H-2 also showed robust electrochemical stability over 24 hours under harsh OER conditions, maintaining a current density of 53 mA cm⁻², while experiencing minimal activity loss. Significantly, the nanocomposite yielded an impressive current density of 475 mA cm⁻² with an overpotential of only 308 mV. This study underscores the potential of HNTs as a cost-effective and abundant material for designing efficient catalysts for OER.