Synthesis of BiVO₄via oxidant peroxo-method: insights into the photocatalytic performance and degradation mechanism of pollutants

Abstract

This paper reports the synthesis of monoclinic bismuth vanadate (BiVO 4 ) by the oxidant peroxide method with crystallization under hydrothermal conditions, and its catalytic performance on the photodegradation of pollutants under visible-light. The as-synthesized BiVO 4 materials were characterized by means of XRD, EDX, Raman spectroscopy, UV-Vis DRS and FEG-SEM. The hydrothermal treatment above 80 °C 10 was required to obtain pure monoclinic BiVO 4 phase by releasing V 5+ ions from vanadium peroxo complexes. With the increase in hydrothermal reaction temperature, the particle size decreased. All BiVO 4 samples presented large size and shape distribution and band gap of approximately 2.40 eV. The as-prepared BiVO 4 catalysts showed high photoactivity for decomposition of model pollutants, methylene blue and rhodamine B dyes, under exposure to visible-light. The photodegradation mechanism was 15 evaluated by adding scavengers, DMSO and KBrO 3 , which were used to probe • OH radical and conduction band (CB) electrons, respectively. It was observed that photodegradation of MB and RhB dyes is caused by the action of • OH radicals, and that BiVO 4 CB electrons do not have reduction potential sufficiently high to reduce dissolved oxygen to O 2 -• . It was proven that the indirect mechanism, i.e. • OH radical formation, plays the major role on the BiVO 4 -assisted photodegradation process. 20

Synthesis of ZnO Nanoparticles Assisted by N Sources and their Application in the Photodegradation of Organic Contaminants

“…Hence, the kinetic constants for formation of HTPA and . OH radicals are similar, so the rate constant for . OH radical ( k OH ) generation could be obtained by applying the pseudo‐zero‐order reaction equation to the HTPA formation data (Figure b).…”

“…In a typical procedure, photocatalyst (10 mg) was placed in contact with an aqueous solution of MB (20 mL, 10 mg L −1 ). All the experiments employed a photoreactor equipped with six UVC lamps (Philips TUV, 15 W, maximum emission at 254 nm and average light intensity of 40 W m −2 ; see the spectral distribution in Figure S8 in the Supporting Information), a magnetic stirrer, and a heat exchanger that maintained the temperature at 18 °C. The photodegradation of the MB dye was monitored at regular intervals by using a Shimadzu UV‐1601 PC spectrophotometer in the visible range, as this molecule exhibits maximum absorbance at 654 nm.…”

An Electrochemically Treated BiVO4 Photoanode for Efficient Photoelectrochemical Water Splitting

“…Compared to the XRD pattern of BVO ( Figure 1d), there is no obvious difference in the XRD pattern of E-BVO (Figure 4a), indicating that electrochemical treatment does not change the crystal structure and phase purity of BiVO 4 . Raman spectra of BVOand E-BVOexhibit typical characteristics of monoclinic BiVO 4 (Figure 4b) [25] without obvious spectra shifts after electrochemical treatment. However, Raman peaks of E-BVOb ecome weaker than those of BVO, which might be associated with the degradation of material crystallinity caused by the formation of defects such as oxygen vacancies, [12] which is further confirmed by XPS.…”

High Photocatalytic Performance of Pd/PdO‐Supported BiVO4 Nanoparticles for Rhodamine B Degradation under Visible LED Light Irradiation

“…All BiVO 4 samples show a major peak at ∼550 nm, indicating that Pd/PdO‐decorated m‐s BiVO 4 samples can absorb solar energy in the visible light region. The optical band gaps of all catalysts could be evaluated from the Tauc equation (Figure B) ,. The E g values of the samples were slightly decreased from 2.312 to 2.203 eV as the weight ratio percentage of Pd/BiVO 4 increases from 0 to 3% (Table 3).…”