scholarly journals Facile Fabrication of Flower-Like BiOI/BiOCOOH p–n Heterojunctions for Highly Efficient Visible-Light-Driven Photocatalytic Removal of Harmful Antibiotics

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1571 ◽  
Author(s):  
Shijie Li ◽  
Bing Xue ◽  
Chunchun Wang ◽  
Wei Jiang ◽  
Shiwei Hu ◽  
...  

Novel heterojunction photocatalysts with remarkable photocatalytic capabilities and durability for degrading recalcitrant contaminants are extremely desired; however, their development still remains quite challenging. In this study, a series of flower-like BiOI/BiOCOOH p–n heterojunctions were fabricated via a controlled in situ anion-exchange process. During the process, BiOI formation and even deposition on BiOCOOH microspheres with tight interfacial contact were realized. As expected, BiOI/BiOCOOH heterojunctions revealed remarkable enhancements in photocatalytic antibiotic degradation capacities under visible light irradiation compared with pristine BiOI and BiOCOOH. The best-performing BiOI/BiOCOOH heterojunction (i.e., IBOCH-2) showed much improved photocatalytic CIP degradation efficiency of approximately 81- and 3.9-fold greater than those of bare BiOI and BiOCOOH, respectively. The eminent photocatalytic performances were due not only to the enhanced capability in harvesting photon energies in visible light regions, but also the accelerated separation of electrons and holes boosted by the p–n heterojunction. Active species trapping tests demonstrated that superoxide free radicals (•O2−) and photo-generated holes (h+) were major active species for CIP degradation. Recycling experiments verified the good durability of BIBO-2 over four runs. The facile in situ synthesis route and excellent performance endow flower-like BiOI/BiOCOOH heterojunctions with a promising potential for actual environmental remediation.

2018 ◽  
Vol 9 ◽  
pp. 2297-2305 ◽  
Author(s):  
Shijie Li ◽  
Wei Jiang ◽  
Shiwei Hu ◽  
Yu Liu ◽  
Yanping Liu ◽  
...  

Developing highly active and durable visible-light-driven photocatalysts for the degradation of toxic pollutants is of vital significance. Herein, Ag2CO3 nanoparticles were in situ formed on Bi2MoO6 microflowers to produce Ag2CO3/Bi2MoO6 heterostructures via a facile procedure. The morphologies, phases, chemical compositions, and optical properties of Ag2CO3/Bi2MoO6 were examined by multiple characterization techniques. The Ag2CO3/Bi2MoO6 heterostructures exhibited substantially improved performance in the removal of industrial dyes (rhodamine B (RhB), methyl orange (MO), and methyl blue (MB)), and the antibiotic tetracycline hydrochloride (TC), compared with bare Bi2MoO6 and Ag2CO3 under visible-light irradiation. The enhancement of activity was attributed to the high charge-separation capacity, which results from the matched band alignment of the two components. The cycling experiments showed a good durability of Ag2CO3/Bi2MoO6. Holes were found to be the dominant active species accounting for the pollutant degradation. This compound is a promising candidate for wastewater treatment.


2020 ◽  
Vol 13 (05) ◽  
pp. 2051031
Author(s):  
Abulikemu Abulizi ◽  
Hujiabudula Maimaitizi ◽  
Dilinuer Talifu ◽  
Yalkunjan Tursun

A photocatalyst of high-performance hierarchical nitrogen-doped MoS2 (N-MoS2) microsphere was fabricated by an in situ hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB). The as-prepared N-MoS2 microsphere was self-assembled by extremely thin interleaving petals, where CTAB acts as a nucleation site for the formation of the interleaving petals due to the strong interaction between CTA+ and [Formula: see text]. N-MoS2 showed higher N2 fixation ability (101.2 [Formula: see text] mol/g(cat)h) than the non-doped MoS2 under the visible light irradiation, and the improved photocatalytic activity could be ascribed to that the doped N narrows the band gap, and the surface reflecting and scattering effect caused by the hierarchical structure enhance the light adsorption. The trapping experiment of active species was also investigated to evaluate the role of photogenerated electrons in the photocatalytic reaction process. Meanwhile, the possible mechanism for the formation and excellent photocatalytic performance of N-MoS2 microsphere were also presented.


Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 724 ◽  
Author(s):  
Yongkui Huang ◽  
Shuangwu Kou ◽  
Xiaoting Zhang ◽  
Lei Wang ◽  
Peili Lu ◽  
...  

The rational fabrication of direct Z-scheme heterostructures photocatalysts is a pivotal strategy to boost the interfacial charge migration and separation. Herein, direct Z-scheme Bi2WO6/WO3 composites were rationally fabricated for the degradation of bisphenol A combined with the activation of peroxymonosulfate (PMS). The tight interface contact between Bi2WO6 and WO3 was successfully formed by the in situ epitaxial growth of ultrathin Bi2WO6 nanosheets at the surface of WO3 nanorods. The Bi2WO6/WO3 composite presented highly efficient catalytic performance toward degradation of BPA with PMS activation as compared to the WO3 and Bi2WO6. PMS can dramatically boost the photocatalytic activity of the composites. Moreover, the results of active radical scavenging experiments revealed that h+, •O2−, and •SO4− are critical active species in the photodegradation reaction. Finally, the photocatalytic mechanism for the degradation of BPA is also discussed in detail. The great improvement of photocatalytic performance should be ascribed to the effective formation of the direct Z-scheme heterojunctions between Bi2WO6 and WO3, resulting in improved light absorption, an efficient transfer and separation of photoinduced charge carriers, and a considerable amount of the electrons and holes with strong reduction and oxidation abilities. The study might provide new inspirations to design and construct heterostructured nanomaterials with outstanding photoactivity for environmental remediation.


RSC Advances ◽  
2015 ◽  
Vol 5 (52) ◽  
pp. 41385-41392 ◽  
Author(s):  
Xin Wang ◽  
Wei Wang ◽  
Xuejiang Wang ◽  
Jing Zhang ◽  
Zaoli Gu ◽  
...  

Floatable photocatalyst for in situ environmental remediation with enhanced visible light driven photocatalytic activity.


Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 788
Author(s):  
Beibei Zhang ◽  
Lu Zhang ◽  
Yulong Zhang ◽  
Chao Liu ◽  
Jiexiang Xia ◽  
...  

In this work, a simple chemical precipitation method was employed to prepare spherical-like Ag3PO4 material (IL-Ag3PO4) with exposed {111} facet in the presence of reactive ionic liquid 1-butyl-3-methylimidazole dihydrogen phosphate ([Omim]H2PO4). The crystal structure, microstructure, optical properties, and visible-light photocatalytic performance of as-prepared materials were studied in detail. The addition of ionic liquids played a crucial role in forming spherical-like morphology of IL-Ag3PO4 sample. Compared with traditional Ag3PO4 material, the intensity ratio of {222}/{200} facets in XRD pattern of IL-Ag3PO4 was significantly enhanced, indicating the main {111} facets exposed on the surface of IL-Ag3PO4 sample. The presence of exposed {111} facet was advantageous for facilitating the charge carrier transfer and separation. The light-harvesting capacity of IL-Ag3PO4 was larger than that of Ag3PO4. The photocatalytic activity of samples was evaluated by degrading rhodamine B (RhB) and p-chlorophenol (4-CP) under visible light. The photodegradation efficiencies of IL-Ag3PO4 were 1.94 and 2.45 times higher than that of Ag3PO4 for RhB and 4-CP removal, respectively, attributing to a synergy from the exposed {111} facet and enhanced photoabsorption. Based on active species capturing experiments, holes (h+), and superoxide radical (•O2−) were the main active species for visible-light-driven RhB photodegradation. This study will provide a promising prospect for designing and synthesizing ionic liquid-assisted photocatalysts with a high efficiency.


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