Enhanced photocatalytic activity of Bi24O31Br10 microsheets constructing heterojunction with AgI for Hg0 removal

Abstract

A range of AgI modified Bi24O31Br10 heterojunction microsheets were produced by a hydrothermal subsequent deposition-precipitation method for highly efficient photocatalytic removal of Hg0 under fluorescent light irradiation. Diverse characterization techniques such as XRD, BET, SEM, TEM, UV − vis DRS, XPS, PL, and ESR were implemented to investigate the properties of the as-fabricated materials. The experimental parameters such as AgI content, sample dosage, pH value of solution, reaction temperature, FSL illumination, inorganic anions, SO2 and NO were employed to evaluate the activity of the materials. It was found that the AgI material was successfully deposited on the surface of Bi24O31Br10 microsheets. In comparison, the dramatic enhancement photocatalytic performance of AgI-Bi24O31Br10 could be assigned to synergies of Bi24O31Br10 and AgI under fluorescent light irradiation, including effective electron-hole separations and generation of photocatalytic active substances at the interfaces of the two semiconductors. AgI loading, inorganic carbonate ion contents and SO2 gas all had significant influence on the removal of Hg0. The 2% AgI-Bi24O31Br10 sample was testified to exhibit an extraordinary enhanced photocatalytic activity. On the basis of the results of ESR detection and radical trapping experiments, reactive substances O2− and h+ were significant players in the photocatalytic reaction.