Enhanced Electrochemical Behaviors of Ti₃C₂ MXenes/Polypyrrole Polymer Composites as Electrode Materials for Electrocatalytic Water Splitting

MXenes have a wide range of applications in energy devices, sensors, lithium-ion batteries, sodium-ion batteries, and supercapacitors due to their novel two-dimensional (2D) layered carbides or carbonitride structure, high electrical conductivity, large specific surface area, and excellent electrochemical properties. Several MXene composites with carbon nanotubes and graphene, have been studied for energy devices over the past years, but these composites sometimes lack various structural and electrochemical properties, directing research toward more flexible solutions, literally and metaphorically. Polymers are an excellent choice for synthesizing MXene composites due to their versatility, compatibility, and low cost. Polypyrrole (PPy) has been widely used in energy devices as an outstanding conducting polymer due to its high theoretical specific capacity, reversible electrochemical redox characteristics, and high conductivity. However, pristine PPy tends to agglomerate together, which may hinder the diffusion of electrolyte ions. Many researchers have concentrated their efforts in recent years on the combination of conducting polymers and carbon materials to improve the electrochemical performance. In the present work, we present the synthesis of Ti₃C₂MXene/PPy composite via in-situ polymerization of pyrrole monomer. Comprehensive morphological, structural and electrochemical studies were carried out to develop the understanding of Ti₃C₂MXene/PPy composite with the fundamentals of electrochemistry. Inherent electrochemical behaviours were studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), chronoamperometry, and linear sweep voltammetry (LSV). The studies revealed that the current density of Ti₃C₂MXene/PPy composite is several folds higher than PPy_,which attributes to high electrocatalytic activity. Further, electrochemical surface area (ECSA) of Ti₃C₂MXene/PPy composite has been determined to investigate the electron transfer kinetics and specific catalytic activity. We investigated the electrocatalytic water splitting activity of Ti₃C₂MXene/PPy composite_,for electrocatalytic green hydrogen fuel production (>90% faradaic efficiency) by water splitting. This observed enhancement we attributed to the improved electrocatalytic behaviors of Ti₃C₂MXene/PPy composite, which stimulates the chemical reaction, as supported with DFT calculations. This study makes a big splash by demonstrating MXene/polymer composites for clean and green hydrogen energy production.