Influence of various sacrificial reagents on congo red degradation and H2O2 production based on heteroanionic titanium oxycarbide photocatalyst and its mechanism

Abstract

Combining a rational design strategy with a simple synthetic method to produce an eco-friendly material presents a unique challenge in photocatalysis technology. This work reports the successful synthesis of a heteroanionic titanium oxycarbide photocatalyst—TiO0.25C0.75 (TiOC) via a solid-state reaction and employed for the decomposition of Congo red (CR) and H2O2 generation from water under visible light radiation. Initially, TiOC demonstrated a moderate CR degradation efficiency of 54% (1 g/L) in 120 min and evolved a minimal amount of H2O2 after 90 min (2 mmol) and 120 min (10 mmol) of light exposure. This clearly indicates that the localization of hybridization of O-2p and C-2p orbitals and a more positive conduction band edge (CB) of TiOC lead to reduced carrier mobility and, consequently, high recombination of photogenerated charge carriers. Therefore, sacrificial reagents such as H2O2 and isopropyl alcohol (ISA) were employed to improve CR removal and H2O2 evolution rate, resulting in 70% and 21.5 mmol (120 min), respectively.