Synthesis, Analysis, and Testing of BiOBr-Bi₂WO₆Photocatalytic Heterojunction Semiconductors

Abstract

In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation ofRhodamine B (RhB)under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.

Enhanced Photocatalytic Activity of BiOBr/ZnO Heterojunction Semiconductors Prepared by Facile Hydrothermal Method

“…It is because the heterojunctions were partially covered by excess BiOBr, which deteriorated its enhancement effect. To further explore the reaction kinetics, pseudo-first order theory was applied in this system via plotting ln( / ) versus shown in Figure 8 [26]. The perfect linear relationship proved the feasibility of using this model [27].…”

Visible Light Photocatalytic Degradation of Methylene Blue and Malachite Green Dyes with BaWO4-Go Nano Composite

“…The removal efficiency of dye (MG/MB) was 90% in the first run, 60% in second run and 25% in the third run over 80-150 min under visible light irradiation shown in Fig-15 and table 5&6 . The slight decrease can be attributed to the loss of photocatalysts between two runs and some refractory intermediates adsorbed on their surface which are difficult to be destroyed [36]. Despite this slight reduction in removal efficiency, the stability of the reused BaWO4-GO photocatalysts after degradation of dye (MG/MB) is still significant.…”

Synergetic photoelectrocatalytic reactors for environmental remediation: A review

“…Based on the research on photocatalysis technology done for the review, a wide range of photocatalytic reactor designs have been reviewed [21,22,24,27]. Comparatively, this review will summarize the recent development of the synergetic photoelectrocatalytic reactor designs divided into the slurry system and the immobilized system, and will include the comprehensive introduction and comparison between various photoelectrocatalytic reactor configurations.…”

“…As a whole, two distinct areas have been studied on heterogeneous photocatalysis: the basic theoretical chemical investigation, including the photocatalytic mechanisms, the kinetic analysis, synthesis and modification of photocatalysts, etc. [15][16][17][18][19][20][21][22], and the industrial scale-up studies which are associated with the photocatalytic reactor design [23][24][25]. Even though much more attention was focused on the modification of as-…”