Study of Sheetlike BiOI/Rodlike Bi₅O₇I Composite Photocatalyst by In Situ Crystallization of BiOI with pH-Dependence for Hg⁰ Removal

Abstract

The sheetlike BiOI/rodlike Bi5O7I photocatalysts were prepared through an in situ crystallization method of BiOI with different pH values under alkaline condition. All the physicochemical properties of samples were tested by chemical characterization analysis. The results showed that the different preparation conditions of BiOI photocatalysts presented different microstructures under different pH values. When the value of pH increased from 8 to 14, the morphology of the sample gradually changed from sheetlike to rodlike. It was found that the formation of heterostructures can be constructed between sheetlike BiOI and rodlike Bi5O7I photocatalysts. Also, the photocatalytic ability of photocatalysts was tested via removing Hg0 under visible-light irradiation. All heterostructure photocatalysts exhibited outstandingly enhanced performance under the light-emitting diode (LED) lamp irradiation without any sacrificial agents in the environment. It was demonstrated that sample Bi-11.0 showed high activity in removing mercury, and the removal efficiency reached up to 63%, which improved the mercury-removal efficiency about 66.7% compared with Bi-8.0. The prominent photocatalytic performance was attributed to the internal electric field of different morphologies and the heterojunction between sheetlike BiOI and rodlike Bi5O7I, which impeded the recombination of photoelectron and hole (e––h+) pairs. This Article provides a new prospect for designing efficient photocatalysts to deal with heavy metal pollution and other environmental problems.

Templating Unidirectional Bismuth Oxyiodide Crystal Growth with Layered Silicates for Enhanced Photocatalysis

“…In addition, XRD revealed that the crystal structure of Lap-BiOI-pH3 shows increased growth along (110), ( 103), ( 200), (202), and (212) planes of BiOI, whereas Lap-BiOI-pH11 appears to be a mix of BiOI and Bi 5 O 7 I (Figure S8). 43,44 These findings were supported by MD simulations, which showed that layered silicate nanosheets at high pH had little association with PVP at either the edge or basal surface of the clay (Figure 4c−g).…”

Recent progress in perylene diimide supermolecule-based photocatalysts

“…Currently, several heterojunctions have been reported between PDIs and bismuth-based semiconductors, including PDIs/BiVO 4 , 41 PDIs/Bi 2 W 2 O 6 , 42,43 PDIs/Bi 2 O 4 , 44 PDIs/BiOBr/Bi 4 O 5 Br 2 , 45 and PDIs/BiOX (X = Cl, Br, I). 28,45,46 For example, Ji et al 47 developed a novel type II heterojunction of aky-like BiOCl/PDIs by adjusting the selfassembly time of PDIs. Comparing the photocatalytic activity of the rst self-assembled PDIs with BiOCl (BiO-Cl/PDIs-1) to the second self-assembly with PDI BiOCl (BiOCl/PDIs-2), it was found that the latter showed a better performance for the degradation of cationic dyes.…”

Research Progress on CO2 Photocatalytic Reduction with Full Solar Spectral Responses

“…As early as the 1930s, it was found that TiO 2 could bleach dyes and degrade fibers in the presence of oxygen and under ultraviolet irradiation, and it was confirmed that TiO 2 remained stable before and after the reaction . Since its discovery in the 1970s, photocatalysis technology has become an perfect technology to alleviate the energy crisis, help with environmental pollution control, − and form new countermeasures for superbugs and epidemic viruses . Since the discovery of the catalytic characteristics of semiconductors, people have begun to explore the factors affecting the reaction process of semiconductor photocatalysis.…”