Quantum sized engineering of FeTiO3 perovskite for enhanced photocatalytic mineralization of antibiotics: Comprehensive exploration of roles of NCQDs and BNQDs in charge transfer dynamics

Abstract

Antibiotics can cause great risk to the environment and human health. Photocatalysis is an effective technology with the potential to eliminate toxic and persistent compounds from water sources. Ferrite titanate (FeTiO3), a type of perovskite catalyst with a small band gap, shows high potential in wastewater treatment processes, but its photocatalytic activity is limited due to its high recombination rate and inadequate charge transfer rate. Herein, we presented quantum sized engineering of FeTiO3 to regulate its optical features by construction with metal-free boron nitride quantum dots (BNQDs) and nitrogen-doped carbon quantum dots (NCQDs). The incorporation of QDs into the perovskite structure enhanced visible light absorption, improved exciton dissociation, accelerated charge transfer, and increased the surface oxygen vacancies. Benefiting from the advantages, the FeTiO3/QDs catalysts displayed enhanced antibiotic decomposition efficiency, as evidenced by the degradation rates of 71.6% and 87.4% for FeTiO3/BNQDs and FeTiO3/NCQDs, respectively, which were higher than that of sole FeTiO3 (66% degradation). The origin of higher photocatalytic performance of the FeTiO3/QDs catalysts was assigned to the boosted separation of charge pairs in which NCQDs promoted electron transfer while BNQDs acted as hole trapper. The effects of oxidants (hydrogen peroxide, peroxymonosulfate) and solution pH on the photocatalytic performance were investigated. This work provides a comprehensive exploration of roles of NCQDs and BNQDs in charge transfer dynamics of FeTiO3 perovskite and introduces highly efficient photocatalysts for green environmental remediation.