Zhong-Ting Hu
Nanyang Technological University, Singapore
Title: Nanoscaled material design: Bi2Fe4O9/Ag with graphene-wrapping tribrid composite with superior capability for environmental decontamination via visible-light-driven photo-fenton oxidation and physical adsorption
Biography
Biography: Zhong-Ting Hu
Abstract
Nanoscaled material design is an efficient method to improve the drawback of the pristine material or fabricate a multifunctional material combining their individual functions. As many investigations have proved that semiconductor/metal composite can exhibit enhanced photocatalysis because of the plasmonic (enhance light harvesting) and electrical conduction (charge separation) properties of noble metal NPs. However, the efficiency of a photocatalyst is determined not only by the charge separation of photogenerated electron/hole pairs but also by that of the recombination effect. Herein, a novel ternary oxide (bismuth ferrite) is selected as the research subject and the corresponding cuboid-like Bi2Fe4O9/AgNP with graphene-wrapping tribrid nanoarchitecture was fabricated using a delicate multi-step synthesis process. It is designed to effectively enhance the performance of the pristine Bi2Fe4O9 in organic pollutants removal (up to 97% of methylene blue (MB) removal in 30 min under visible-light irradiation) through ternary collaboration among Bi2Fe4O9, silver nanoparticles (AgNPs) and reduced graphene oxide (rGO). The challenges, such as mass transfer of pollutants in water treatment, recombination of electrons/holes and interconversion between Fe(III) and Fe(II) states within Bi2Fe4O9, could be addressed effectively. The resulting samples (i.e., Bi2Fe4O9/Ag/rGO, Bi2Fe4O9/Ag and Bi2Fe4O9) were characterized by various techniques and their differences in physical and chemical properties were investigated. Meanwhile, their applications in organic pollutants removal were assessed via photo-Fenton oxidation and photocatalysis under visible-light irradiation. The findings demonstrate the individual functions of AgNP (i.e., electrical conduction, enhanced interconversion of Fe(III)/Fe(II)) and rGO (i.e., anti-recombination of electrons/holes, enhanced mass transfer of organic pollutants) within the Bi2Fe4O9/Ag/rGO composite. The schematic illustration of the mechanism of organic pollutants removal using the multi-functional Bi2Fe4O9/Ag/rGO is proposed.