Fast Scalable Synthetic Methodology to Prepare Nanoflower‐Shaped Bi/BiOCl_xBr_1−x Heterojunction for Efficient Immobilized Photocatalytic Reactors under Visible Light Irradiation

Abstract

the photoinduced charge carriers. [8][9][10] Besides, it is highly desirable to achieve these goals using earth-abundant materials and a cost-effective, energy-efficient, and scalable preparation strategy for large-scale photocatalytic systems.Recently, bismuth oxyhalides (BiOXs, X = Cl, Br, and I) have demonstrated excellent photocatalytic activity under sunlight irradiation due to their distinct characteristics such as indirect bandgap, excellent electronic configuration, unique layered structures, high dipole moment, powerful oxidation ability, and high separation rate of photogenerated electron-hole pairs. [11][12][13][14] Despite the distinct optical and structural characteristics of BiOXs, they show some drawbacks that limit their practical application. For instance, BiOBr has a narrow bandgap energy ≈2.7-2.8 eV absorbing the visible light component of the solar spectrum; however, its photocatalytic performance is relatively poor due to its low separation rate of charge carriers and weak oxidation ability. [8,15] On the other hand, BiOCl possesses a more powerful oxidation ability but with a wide bandgap energy (≈3.3 eV), thus responding to only UV light, which represents a small percentage (≈5%) of the solar spectrum, and reducing its chance for scalable remediation of environmental pollution. [16,17] Consequently, the integration of the desired characteristics of individual BiOXs in one photocatalytic compound is an effective strategy to produce more efficient BiOXs-based photocatalytic systems. For example, alloyed compounds (i.e., solid solutions) of BiOXs which contain more than one halogen atom in the compound through changes in the molar ratios of halogen atoms such as BiOCl x Br 1−x , [18,19] BiOCl x I 1−x , [20,21] and BiOBr x I 1−x . [22,23] have the same layered atomic structure, leading to the easy arrangement of different halogen atoms into the lattice of solid solutions using a low-energy fabrication process. Based on this fact, the solid solutions strategy is one of the most effective ways to improve the photocatalytic performance of BiOXs by reaching the best balance between the visible light absorption and reduction-oxidation (redox) abilities. [19,20,23] Among the different solid solutions of BiOXs, flower-like BiOCl x Br 1−x solid solutions (i.e., engineering BiOCl by introducing different molar ratios of Br) demonstrate superior photocatalytic performance compared to their counterparts. In previous studies, BiOCl x Br 1−x solid solutions were prepared by following two typical strategies, either by introducing organic salts (cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC)) as a source for halogen with different molar ratios using multistep methods at ambient conditions [19,24,25] or by using simple salts (KCl and KBr) as a source for halogen ions using the hydrothermal or solvothermal methods. [26][27][28] In fact, the first strategy is a lengthy process that requires expensive and complex organic materials as halogen sources and indisposable surfactants, ...

Regulating the Electronic Structure of Bismuth Nanosheets by Titanium Doping to Boost CO2 Electroreduction and Zn–CO2 Batteries

“…Notably, the Ti 2p peak intensity of Ti-Bi NSs was significantly weaker than that of Bi 4 Ti 3 O 12 , indicating a large amount of Ti peeled off from the Bi 4 Ti 3 O 12 material, consistent with the doping characteristics of Ti-Bi NSs. [36,37] The CO 2 reduction performance of Ti-Bi NSs electrocatalyst was investigated by using a flow cell in a 1.0 M KOH solution (Figure S8, Supporting Information). To deeply understand the effect of ultrathin Ti-Bi NSs on the catalytic CO 2 electroreduction, Bi NSs, and Bi powder were selected as a comparison.…”

Recent Progress of Carbon Dots for Air Pollutants Detection and Photocatalytic Removal: Synthesis, Modifications, and Applications

“…In recent years, extensive reports have demonstrated that semiconductor photocatalysts can degrade a wide range of inorganic and organic pollutants. [183][184][185][186][187] What's more, the functional CDs have also been regarded as promising modifiers that can be utilized for decorating photocatalysts to improve their degradation performance, because of the multiple roles such as accelerating carriers separation, increasing spectral absorption, regulating energy band, and providing adsorption sites. [188] This section will introduce the applications of the CDs-based photocatalysts in photocatalytic degradation of typical inorganic and organic gaseous contaminants (NO x and VOCs) and explore the mechanism for enhancing the hybrid nanocomposite performance.…”

Recent advances in the application of magnetic bio-polymers as catalysts in multicomponent reactions

“…14–18 Overall, due to the properties of ferrite magnetic nanomaterials and hexaferrite (M-type), they can be used for the adsorption of various metals ions, cationic and anionic dyes from wastewater. 19–23…”