Abstract
Porous ZnGa2O4 microspheres (P-ZGO) are synthesized by a facial glucose-mediated microwave hydrothermal method followed by annealing. The morphological, photoelectric and photocatalytic properties of the as-prepared P-ZGO sample are characterized in detail, and the results show that the P-ZGO photocatalyst has a good crystallinity, large species surface area, hierarchical mesoporosity, and distinguished photoelectric properties. Under 254 nm UV irradiation, the P-ZGO sample shows a much higher activity and stability than TiO2 in the photocatalytic degradation of gas-phase aromatic pollutants. The average conversion efficiencies of toluene and benzene over P-ZGO are ~56.6% and ~44.3%, and with corresponding mineralization rates of ~86.3% and ~65.2%, respectively. No remarkable deactivation of P-ZGO is observed in a 60 h heterogeneous photoreaction. Furthermore, the as-prepared P-ZGO sample also shows an excellent photocatalytic efficiency (up to 99.8%) for the liquid-phase As(III) removal from water. The distinguished photocatalytic performance of P-ZGO can be ascribed to its unique electronic structures and hierarchical morphologies. According to the results of our analysis, a possible mechanism is also proposed to elaborate the photocatalytic oxidation process in the pollutants/P-ZGO system.
Highlights
IntroductionPhotocatalytic oxidation technology using semiconductors (TiO2 , ZnO, etc.) as photocatalysts has been verified to be a “green” and sustainable approach for ecological environment remediation [1,2,3,4]
Photocatalytic oxidation technology using semiconductors (TiO2, ZnO, etc.) as photocatalysts has been verified to be a “green” and sustainable approach for ecological environment remediation [1,2,3,4].In the past decades, most applications have been focused on the purification of the indoor air environment and water environment at a room temperature [5,6,7,8]
According to the Debye–Scherrer equation, the average crystallite sizes of these three ZnGa samples can be calculated based on the FWHM value of the (111) diffraction peak, and the results are listedThe in Table morphologies of the products are examined by field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM)
Summary
Photocatalytic oxidation technology using semiconductors (TiO2 , ZnO, etc.) as photocatalysts has been verified to be a “green” and sustainable approach for ecological environment remediation [1,2,3,4]. The practical performance of most semiconductor photocatalysts requires a further enhancement due to its low quantum efficiency or/and easy deactivation. Many studies have reported that the p-block semiconductors are a new generation of extremely effective and stable photocatalysts for environmental remediation. Zinc Gallate (ZnGa2 O4 ), a typical p-block wide bandgap semiconductor, exhibits an excellent photocatalytic performance in environmental purification [16,17,18], the reduction of CO2 to methane [19] and water splitting [20,21]. Its width improving theimproving separation the of charge carriers combination its width bandgap bandgap the ZnGa. ZnGa2structure, O4 is expected to provide photogenerated charges with a strong redox capability an capabilityphotocatalytic for an excellent photocatalytic performance [23,24]. Our “brick-mortar” strategy is to use a carbonaceous polymer (from the polycondensation a carbon precursor) as “mortar”
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