One-Step Synthesis of Hierarchical Flower-like SnO₂/BiOCOOH Microspheres with Enhanced Light Response for the Removal of Pollutants

Abstract

The low separation rate of electron−hole pairs in singlecomponent photocatalysts severely limits their applications for wastewater treatment. For this study, SnO 2 /BiOCOOH photocatalysts in flower-like microspheres were controllably synthesized via a one-step hydrothermal method and were characterized by various advanced techniques. These SnO 2 /BiOCOOH nanocomposites demonstrated excellent photocatalytic activities for the degradation of rhodamine B (RhB), titan yellow, and levofloxacin hydrochloride (LVF). Specifically, 98.5% of RhB, 80% of titan yellow, and 85% of LVF were degraded under 5 W LED (λ = 365 nm) light irradiation within 30, 40, and 60 min, respectively. Radical trapping experiments and electron spin resonance results indicated that h + was the dominant active radical, whereas •O 2 − and •OH played an auxiliary role in the photocatalytic system. Subsequently, a potential photocatalytic mechanism was proposed based on the experimental results.

Enhanced performance for Rhodamine B degradation over SnO2/BiOBr photocatalyst

“…The EIS measurements were used to evaluate the interface reaction ability of the photo‐generated electron‐hole pairs and migration property in photocatalytic materials. [ 33–35 ] The Nyquist plots (Figure 9) of pristine BiOBr, SnO 2, and 7%SnO 2 /BiOBr composites were demonstrated. It is obvious that the arc radius of 7%SnO 2 /BiOBr is the smallest one.…”

“…However, the e − could connect with O2 and H + to produce H2O2 ( E 0 [O2/H2O2] = +0.695 V NHE for two‐electron reduction). [ 33 ] The potential of the VB of the BiOBr was 2.995 eV, so the holes (h + ) in the VB of BiOBr excited by the visual light can cause a straightforward decomposition of RhB molecules or a reaction with water to produce •OH radicals ( E 0 [H 2 O/•OH] = 2.40 eV V NHE ) that subsequently degenerate RhB molecules. Then •O 2 − was formed through the reaction of H2O2 and •OH.…”

“…Then •O 2 − was formed through the reaction of H2O2 and •OH. [ 33 ] Such radicals produced the main contribution to the degeneration of RhB molecules. Eventually, the separation between electrons and holes leads to the degradation of RhB.…”

“…Therefore, the photoexcited electrons that remained in the CB of SnO2 cannot reduce O 2 adsorbed on the surface of SnO2 to generate However, the e À could connect with O2 and H + to produce H2O2 (E 0 [O2/H2O2] = +0.695 VNHE for twoelectron reduction). [33] The potential of the VB of the BiOBr was 2.995 eV, so the holes (h + ) in the VB of BiOBr excited by the visual light can cause a straightforward decomposition of RhB molecules or a reaction with water to produce…”

Photocatalytic Conversion of Fructose to Lactic Acid by BiOBr/Zn@SnO2 Material

“…The coupling of SnO 2 with Bi-containing semiconductor materials has been studied as a new trend for composites that can improve photocatalytic performance [21]. Due to the traditional preparation methods, which are time-consuming, energy-intensive and have low purity [22], some other methods were referenced in this study, such as modified SnO 2 with BiOBr in one pot [23,24]. In this research, BiOBr and SnO 2 were chosen as original semiconductor materials.…”