Bifunctional Co ₃O ₄/g-C ₃N ₄ Hetrostructures for Photoelectrochemical Water Splitting

Abstract

This study explored the synergistic potential of photoelectrochemical water splitting through bifunctional Co ₃O ₄/g-C ₃N ₄ heterostructures. This novel approach merged solar panel technology with electrochemical cell technology, obviating the need for external voltage from batteries. Scanning electron microscopy and X-ray diffraction were utilized to confirm the surface morphology and crystal structure of fabricated nanocomposites; Co ₃O ₄, Co ₃O ₄/g-C ₃N ₄, and Co ₃O ₄/Cg-C ₃N ₄. The incorporation of carbon into g-C ₃N ₄ resulted in improved catalytic activity and charge transport properties during the visible light-driven hydrogen evolution reaction and oxygen evolution reaction. Optical properties were examined using UV–visible spectroscopy, revealing a maximum absorption edge at 650 nm corresponding to a band gap of 1.31 eV for Co ₃O ₄/Cg-C ₃N ₄ resulting in enhanced light absorption. Among the three fabricated electrodes, Co ₃O ₄/Cg-C ₃N ₄ exhibited a significantly lower overpotential of 30 mV and a minimum Tafel slope of 112 mV/dec This enhanced photoelectrochemical efficiency was found due to the established Z scheme heterojunction between Co ₃O ₄ and gC ₃N ₄. This heterojunction reduced the recombination of photogenerated electron–hole pairs and thus promoted charge separation by extending visible light absorption range chronoamperometric measurements confirmed the steady current flow over time under constant potential from the solar cell, and thus it provided the effective utilization of bifunctional Co ₃O ₄/g-C ₃N ₄ heterostructures for efficient solar-driven water splitting.