In Situ Polymerization of Thiophene on Biochar-Supported Bismuth Ferrite for Enhanced Electrochemical Hydrogen Evolution Reaction

The design and development of heterogeneous electrocatalysts via interface engineering represent a promising and necessary strategy for constructing a highly efficient hydrogen-based economy. The slow kinetics and high activation energy of the hydrogen evolution reaction (HER) necessitate the development of effective electrocatalysts to reduce the energy barrier, enabling lower overpotentials. In this work, we demonstrate an oxidative polymerization of different concentrations of thiophene (Th) to polythiophene (PTh) with biochar (BC)-modified bismuth ferrite (BFO) as a template. Among the designed electrocatalysts, BFO-BC/PTh 18 shows the least kinetic overpotential value of 289.62 mV and a Tafel slope of 67.02 mV/dec at a current density of 10 mA/cm 2 . From the material and electrochemical studies, it is clear that a decrease in absorbed oxygen, generation of new active sites, a decrease in crystallite size, and an overall change in the chemical environment of BFO account for the enhanced electrocatalytic activity. Overall, the design and strategy validate an effective pathway for designing a competent electrode for the HER.