Photocatalytic Mineralization of Organic Acids over Visible-Light-Driven Au/BiVO₄Photocatalyst

Abstract

Au/BiVO 4 visible-light-driven photocatalysts were synthesized by coprecipitation method in the presence of sodium dodecyl benzene sulfonate (SDBS) as a dispersant. Physical characterization of the obtained materials was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), UV-Vis diffuse reflectance spectroscopy (DRS) and Brunauer, and Emmett and Teller (BET) specific surface area measurement. Photocatalytic performances of the asprepared Au/BiVO 4 have also been evaluated via mineralizations of oxalic acid and malonic acid under visible light irradiation. XRD and SEM results indicated that Au/BiVO 4 photocatalysts were of almost spherical particles with scheelite-monoclinic phase. Photocatalytic results showed that all Au/BiVO 4 samples exhibited higher oxalic acid mineralization rate than that of pure BiVO 4 , probably due to a decrease of BiVO 4 band gap energy and the presence of surface plasmon absorption upon loading BiVO 4 with Au as evidenced from UV-Vis DRS results. The nominal Au loading amount of 0.25 mol% provided the highest pseudo-first-order rate constant of 0.0487 min −1 and 0.0082 min −1 for degradations of oxalic acid (C 2 ) and malonic acid (C 3 ), respectively. By considering structures of the two acids, lower pseudo-first-order rate constantly obtained in the case of malonic acid degradation was likely due to an increased complexity of the degradation mechanism of the longer chain acid.

Enhancing the photocatalytic activity of ZnO nanoparticles for efficient rhodamine B degradation by functionalised graphene nanoplatelets

“…RhB degradation follows a pseudo first-order reaction (Fig. 3(b)) as described by ln(C t /C 0 ) ¼ k app t where k app is the apparent rate constant (min À 1 ) and t is the reaction time [17]. The highest photocatalytic rate of 0.138 min À 1 (5 wt% f-GNPs), compared with 0.087 min À 1 (ZnO) and 0.002 min À 1 (non-catalysed reaction), is partly ascribed to the increased SSA of the nanocomposite (21.50 m 2 g À 1 ) compared with the pure ZnO (15.20 m 2 g À 1 ).…”

Visible-light-induced Ag/BiVO4 semiconductor with enhanced photocatalytic and antibacterial performance

“…Also, high Ag loading accumulates a high surface density of negatively charged crystallites, where the positively charged photoholes will progressively be preferentially attracted by these particles, and thus will become electron-hole recombination centers inhibiting the reaction. degradation rate, C o /C is the ratio of the dyes at adsorptiondesorption equilibrium and after various intervals of time t and k is the apparent first-order rate constant (min −1 ) [37].…”

Interfacial insights into 3D plasmonic multijunction nanoarchitecture toward efficient photocatalytic performance

“…Extensive research has currently been devoted to the development of visible-lightdriven catalysts with narrower bandgap energies. Since Kudo and coauthors firstly reported the photocatalysis of BiVO 4 (n-type, E g ≈ 2.4 eV) in 1998 [5], BiVO 4 has been one of the most frequently used materials for water purification and splitting due to its activity, chemical neutrality and stability, historical non-toxicity (e.g., the wide application as bright yellow pigment [6]), and environmental benign [7][8][9]. The n-type hematite (α-Fe 2 O 3 , E g ≈ 2.0 eV) is another superior photocatalyst of particular interest because of its low cost, environmental friendliness, easy preparation, and high thermodynamic stability [10][11][12].…”