Synthesis of porous MXene for efficient bifunctional electrocatalysis in overall water splitting: Hydrogen and oxygen evolution reactions

Abstract

Electrocatalytic water splitting is a key process for sustainable energy generation, but its large-scale implementation is hindered by the slow kinetics of the hydrogen evolution (HER) and oxygen evolution reactions (OER). This study introduces a design strategy for two-dimensional (2-D) MXene and porous MXene (P-MXene) nanostructures to enhance water splitting efficiency. By employing advanced etching and structural engineering, P-MXene nano structures with optimized porosity and increased surface area are fabricated, which improving the active site density and promoting rapid ion diffusion. Electrochemical characterizations demonstrate significantly reduced overpotentials and enhanced current densities for both HER and OER, consistently, P-MXene catalyst resulted in the overpotential reduction suggestively by 45 mV for HER and 110 mV for OER at anodic and cathodic current density of 10 m A cm⁻², compared to MXene, surpassing traditional noble-metal catalysts. Furthermore, the P-MXene/NF device delivers the stable current density of 10 mA cm⁻² for overall water splitting at 1.54 V and retained 92.2 % efficiency after 24 h. This work highlights the potential of porous MXene nanostructures in electrocatalysis, offering a scalable approach for the development of bifunctional electrocatalysts for next-generation energy conversion systems.