MXene/CoP hybrid: Role of catalyst/support interaction on enhancing the electrocatalytic water oxidation performance

MXenes (Ti₃C₂Tx) are a class of two-dimensional material that consists of atomically thin layers endowed with unique properties. It exhibits promising electrocatalytic properties in its pristine phase and as a hybrid form. Accordingly, the present work systematically investigated MXene to address the elusive key questions. (i) Is MXene a suitable support material for making a hybrid with other electrochemically active phases? (ii) How does MXene improve the intrinsic properties of a model catalyst of CoP in the hybrid (CoP/MXene)? and (iii) What is the impact of CoP/MXene interface properties on the electrocatalytic water-splitting process of oxygen evolution reactions (OER)? Notably, the synthesized large-scale exfoliated two-dimensional (2D) MXene nanosheets serve as an effective host substrate, enabling the dense and vertically oriented growth of one-dimensional (1D) cobalt hydroxide fluoride (Co(OH)F) nanorods. Subsequent phosphidation yields a highly conductive cobalt phosphide (CoP)/MXene composite, characterized by an abundance of mesopores distributed across the CoP nanorod surfaces. The CoP/MXene heterostructure demonstrates improved specific surface area and a well-defined porous architecture, which collectively enhance electrolyte penetration and optimize mass transport kinetics. The CoP/MXene exhibited enhanced OER performance (ƞ = 230 mV for 10 mA/cm²) compared to the state-of-the-art IrO₂ (ƞ = 270 mV for 10 mA/cm²). The activity enhancement, due to the interplay between MXene support and CoP catalyst, is identified and demonstrated in the present study. These promising findings demonstrate the merits of MXene support for designing various hybrid electrocatalysts for different electrochemical applications.