Conversion of CO2 into renewable fuel over Pt–g-C3N4/KNbO3 composite photocatalyst

Abstract

g-C₃N₄/KNbO₃ composites were fabricated by ultrasonic dispersion followed by heat treatment method, and developed as visible-light-sensitive photocatalysts for CO₂ conversion. The photocatalysts were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectra, nitrogen adsorption–desorption, and UV-vis diffuse reflection spectroscopy. HRTEM revealed that an intimate interface between g-C₃N₄ and KNbO₃ was formed in the g-C₃N₄/KNbO₃ composite. The g-C₃N₄/KNbO₃ composite exhibited superior photocatalytic performance for CO₂ reduction compared to g-C₃N₄ under visible-light illumination. Such a significant enhancement in the photocatalytic activity was mainly ascribed to the improved separation efficiency of photoinduced carriers at the interface of the g-C₃N₄/KNbO₃ composite, which was beneficial for separating the photoinduced electron–holes and thus improving the photocatalytic performance. The present study would provide a useful method to develop an effective composite photocatalyst for CO₂ reduction under visible light irradiation.