Controlled Synthesis of BiOCl Hierarchical Self‐Assemblies with Highly Efficient Photocatalytic Properties

Abstract

Herein, we report the controlled synthesis of bismuth oxychloride (BiOCl) hierarchical self-assemblies under hydrothermal conditions and demonstrate their high photocatalytic properties. An interesting morphological evolution from microplates to nanoplate assemblies with microsphere-, microdisk-, and microflower-like structures is investigated by adjusting the amounts of surfactant poly(vinyl pyrrolidone) (PVP). It has been found that three types of three-dimensional (3D) BiOCl micromaterials are formed layer-by-layer from a large number of interconnected 2D nanoplates with a mean side length of about 20 nm. A possible crystal growth and formation mechanism is proposed as a plausible mechanistic interpretation for the self-assembly of nanoplates into the observed microstructures that is based on the detailed experiments. Furthermore, the photocatalytic properties of the obtained samples are investigated by the photodegradation analysis of Rhodamine B and methylene orange (RhB and MO) dyes, thus indicating that the microspherelike BiOCl hierarchical structure has a higher photocatalytic activity than the microdisk-like and microflower-like BiOCl structures, owing to its novel structure with a high surface area.[a] Dr.

Size-controlled BiOCl–RGO composites having enhanced photodegradative properties

“…However, this region represents only 3%À5% of the solar spectrum, and, furthermore, only few successful examples of dye photodegradation using the single-component BiOCl under visible light irradiation have been reported. [29] Peng [30] described that synthesising BiOCl in the presence of PVP can control the morphology and structure and improve photocatalytic properties. Several approaches to the synthesis of BiOCl-based photocatalysts have been reported.…”

Poly(vinyl pyrrolidone)-assisted hydrothermal synthesis and enhanced visible-light photocatalytic performance of oxygen-rich bismuth oxychlorides

“…It is general accepted that E g value is relevant to a degree of the thickness of nanosheets [30] and in our cases, the thickness of nanosheets are almost identical no matter whether PVP is added or not. The slight shrinkage of band gap energy of three BPx samples may possibly relate to the variable morphology, crystal size, and specific structure, indicating that PVP can be utilized as a structure directing agent for fabricating nanostructures with favorable structural features [28]. As expected, semiconductors with suitable band gaps benefit the absorption and utilization of visible light, and thus further enhancement of photocatalytic efficiency.…”

“…it was also proven by the relatively low intensity of PL peak in BP2 in comparison with other BPx samples [40]. Third, the 3D hierarchical structure has numerous pores on surface, which favors the mass transfer of reactants into the interior and product molecules out, thus promoting the catalytic degradation process [28]. Besides, the enhancement of visible-light harvesting is available through the multiple reflections of incident radiation, which is favorable to the increase of catalytic efficiency [35].…”

“…The anisotropic growth of Bi 12 O 17 Cl 2 nanoparticles was somewhat restrained since PVP molecules adsorbed on the surface of nanoparticles with the steric hindrance from carbon chains as hydrophobic groups, 2D nanosheets are hereby produced in relatively small sizes. Second, selective adsorption of PVP surfactants on various crystal planes and subsequent competition at interfaces pioneered the rotation of adjacent nanoparticles so that 3D hierarchical architectures are constructed via interweaving 2D nanosheets along edges [28]. As a result, the presence of PVP benefits the assembly and interlacement of 2D nanosheets to construct 3D hierarchical microspheres with numerous pores on surface.…”

Does the low optical band gap of yellow Bi3YO6 guarantee the photocatalytical activity under visible light illumination?

“…The peak at the highest binding energy (530.9 eV) marked as A can be assigned to OH groups as it was shown in the case of other metal oxides [46,47]. The second one (B) at 528.7 eV is probably observed due to the presence of lattice metal-oxygen bonds [48][49][50]. The third peak (C) at 526.3 eV may be related to carbon-containing contaminations.…”