scholarly journals Excellent Photocatalytic Rhodamine B Degradation for water Remediation Over Pr3+ Doped Bi2WO6 Microspheres

Author(s):  
Xianghui Zhang

Abstract In this work, a serious of Pr3+ doped Bi2WO6 had been prepared by one-step hydrothermal method without using any additive. XRD results showed that the Pr3+ doped Bi2WO6 possessed pure orthorhombic phase. XRD patterns shifted to higher angles with the doping amount of Pr3+ increasing indicated that Pr3+ was doped into the lattice of Bi2WO6. UV-vis DRS results revealed that the band gap was narrowed by Pr3+ doping. SEM and TEM images showed that the Pr3+ doped Bi2WO6 presented 3D flower-like microspheres constructed by many nanosheets. The photocatalytic activities of the as-prepared samples were evaluated by using rhodamine B (RhB) as the target organic pollutant. It was found that 1% Pr-Bi2WO6 exhibited excellent photocatalytic performance, as well as good stability and reusability. The improved photocatalytic activity can be ascribed to the optimum optical absorption activity, the larger specific surface area and the morphology of microspheres which resulted in the effective separation of the photogenerated electron hole pairs. In addition, the photocatalytic mechanism had been discussed according to the radical-trapping experiments.

2021 ◽  
Vol 10 (2) ◽  
pp. 59-63
Author(s):  
Hai Pham Viet ◽  
Anh Dao Thi Ngoc ◽  
Viet Nguyen Minh ◽  
Ha Tran Thi Viet ◽  
Dang Do Van ◽  
...  

In this study, direct Z–scheme heterostructure CoWO4/g-C3N4 was synthesized by a facile hydrothermal method. The structural, morphological properties of the prepared samples were characterised by XRD, SEM, UV–Vis and PL measurements. The as-obtained heterostructure CoWO4/g-C3N4 exhibited enhanced photocatalytic activities toward the degradation of Rhodamine B under visible light irradiation with 92% Rhodamine B removal after 80 minutes irritation, which exceeded pristine g-C3N4 and CoWO4. The enhanced photocatalytic performance ascribed to interfacial contact between g-C3N4 and CoWO4, thus further inhibiting the recombination of photogenerated electron/hole pairs. It is anticipated that the construction of Z–scheme heterostructure CoWO4/g-C3N4 is an effective strategy to develop high-performance photocatalysts for the degradation of organic pollutants in water.


Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2206
Author(s):  
Gaoqian Yuan ◽  
Gen Zhang ◽  
Kezhuo Li ◽  
Faliang Li ◽  
Yunbo Cao ◽  
...  

Loading a noble metal on Bi4Ti3O12 could enable the formation of the Schottky barrier at the interface between the former and the latter, which causes electrons to be trapped and inhibits the recombination of photoelectrons and photoholes. In this paper, AgPt/Bi4Ti3O12 composite photocatalysts were prepared using the photoreduction method, and the effects of the type and content of noble metal on the photocatalytic performance of the catalysts were investigated. The photocatalytic degradation of rhodamine B (RhB) showed that the loading of AgPt bimetallic nanoparticles significantly improved the catalytic performance of Bi4Ti3O12. When 0.10 wt% noble metal was loaded, the degradation rate for RhB of Ag0.7Pt0.3/Bi4Ti3O12 was 0.027 min−1, which was respectively about 2, 1.7 and 3.7 times as that of Ag/Bi4Ti3O12, Pt/Bi3Ti4O12 and Bi4Ti3O12. The reasons may be attributed as follows: (i) the utilization of visible light was enhanced due to the surface plasmon resonance effect of Ag and Pt in the visible region; (ii) Ag nanoparticles mainly acted as electron acceptors to restrain the recombination of photogenerated electron-hole pairs under visible light irradiation; and (iii) Pt nanoparticles acted as electron cocatalysts to further suppress the recombination of photogenerated electron-hole pairs. The photocatalytic performance of Ag0.7Pt0.3/Bi4Ti3O12 was superior to that of Ag/Bi4Ti3O12 and Pt/Bi3Ti4O12 owing to the synergistic effect between Ag and Pt nanoparticles.


NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850051 ◽  
Author(s):  
Yanan Li ◽  
Zhongmin Liu ◽  
Yaru Li ◽  
Yongchuan Wu ◽  
Jitao Chen ◽  
...  

The Bi2S3-TiO2-RGO composites were synthesized by a facile one-step hydrothermal method and applied for the photocatalytic degradation of Rhodamine B (Rh B) under the visible light. The Bi2S3-TiO2-RGO composites were characterized by transmission electron microscopy, X-ray diffraction, Raman and Fourier transform infrared spectrometer. The results indicated that the Bi2S3-TiO2-RGO composites were successfully prepared, and Ti-O-C and S-C bonds were existing among Bi2S3, TiO2 as well as RGO. Furthermore, the photocatalytic ability of Bi2S3-TiO2-RGO composites was excellent under visible light due to its responding to the whole visible light region, low recombination rate of photogenerated electron–hole pairs and relatively negative conduction band. Rh B photocatalytic degradation rate was 99.5% after 50[Formula: see text]min and still could reach 98.4% after five cycles. Finally, a formation mechanism as well as a photocatalytic mechanism of Bi2S3-TiO2-RGO composites were proposed based on the experimental results.


MRS Advances ◽  
2019 ◽  
Vol 4 (33-34) ◽  
pp. 1887-1893
Author(s):  
Jun Wu ◽  
Yonghui Gong ◽  
Qiang Fu ◽  
Chunxu Pan

ABSTRACTIn this paper, a novel NiFe-LDH@ZnO composite was prepared by using a facile two-step process upon nickel foam (NF) substrate. The morphologies and chemical compositions of the samples were characterized by SEM, EDS, XRD and XPS. Photocatalytic degradation of Rhodamine B dye was tested with the samples NiFe-LDH@ZnO@NF, ZnO@NF and NiFe-LDH under the same conditions. The experimental results revealed that the NiFe-LDH@ZnO@NF composite exhibited excellent photocatalytic performance, i.e., 1.4 and 2.5 times higher than that of pure ZnO and NiFe-LDH, respectively. The reason was that the NiFe-LDH@ZnO@NF composite provided a possibility to effectively inhibit the recombination of the photogenerated electron-hole pairs, and therefore enhanced the photocatalytic efficiency. This composite is expected to have potential applications in wastewater treatment field.


NANO ◽  
2020 ◽  
Vol 15 (04) ◽  
pp. 2050045
Author(s):  
Ning Liu ◽  
Huidong Xie ◽  
Jie Li ◽  
Yajuan Zhao ◽  
Na Wang

Brookite TiO2 was synthesized by a hydrothermal method, g-C3N4 was prepared by a pyrolytic method, brookite/g-C3N4 composites were prepared by a calcining method, and brookite/g-C3N4/BiOBr ternary composites were prepared by loading BiOBr on the surface of brookite/g-C3N4. XRD and XPS analysis of the composites confirmed the formation of brookite TiO2/g-C3N4/BiOBr. SEM and TEM results confirmed the as-prepared composites were nanosized. The optimum loading amount of BiOBr was 30%. The photocatalytic results showed that the brookite/g-C3N4/30%BiOBr composites degraded rhodamine B completely under visible light irradiation. The degradation ratio of brookite/g-C3N4/30%BiOBr toward rhodamine B was nearly 100% for 2[Formula: see text]h, which was much higher than that of brookite TiO2 and brookite/g-C3N4 catalysts. The reason for the improvement of photocatalytic activity might be because the composites promoted the formation of superoxide radicals and the separation efficiency of photogenerated electron-hole pairs. The photocurrent density of the brookite/g-C3N4/30%BiOBr was about 10 times higher than that of pure brookite. In addition, the brookite/g-C3N4/BiOBr showed a good repeatablity of photocatalysis.


NANO ◽  
2018 ◽  
Vol 13 (04) ◽  
pp. 1850045
Author(s):  
Jing Li ◽  
Hongxiao Zhao ◽  
Yan Lei ◽  
Qingyuan Yang ◽  
Zhi Zheng

SnSe2/Se heterojunction films were successfully grown on fluorine-doped tin oxide (FTO) glass for the first time via a one-step solvothermal route using magnetron sputtered Sn metallic precursors, Se powders as selenium source, cyclohexanol as solvent and cyclohexanol as auxiliary solvent, respectively. The SnSe2/Se heterojunction films consisted of Se nanoparticles or nanorods cluster and SnSe2 network surface layers. The crystalline phase and morphology of SnSe2/Se films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), respectively. The photocatalysis measurements of the products for rhodamine Blue (RhB) demonstrated that SnSe2/Se heterojunction films revealed better dye degradation properties than SnSe2 nanosheet films due to the higher separation rates of photogenerated electron–hole pairs of SnSe2/Se heterojunction films, which can be confirmed by surface transient photovoltage (TPV) analyzer.


Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1603 ◽  
Author(s):  
Meiling Sun ◽  
Weichong Kong ◽  
Yunlong Zhao ◽  
Xiaolin Liu ◽  
Jingyue Xuan ◽  
...  

Herein, high-energy {001} facets and Sn4+ doping have been demonstrated to be effective strategies to improve the surface characteristics, photon absorption, and charge transport of TiO2 hierarchical nanospheres, thereby improving their photocatalytic performance. The TiO2 hierarchical nanospheres under different reaction times were prepared by solvothermal method. The TiO2 hierarchical nanospheres (24 h) expose the largest area of {001} facets, which is conducive to increase the density of surface active sites to degrade the adsorbed methylene blue (MB), enhance light scattering ability to absorb more incident photons, and finally, improve photocatalytic activity. Furthermore, the SnxTi1−xO2 (STO) hierarchical nanospheres are fabricated by Sn4+ doping, in which the Sn4+ doping energy level and surface hydroxyl group are beneficial to broaden the light absorption range, promote the generation of charge carriers, and retard the recombination of electron–hole pairs, thereby increasing the probability of charge carriers participating in photocatalytic reactions. Compared with TiO2 hierarchical nanospheres (24 h), the STO hierarchical nanospheres with 5% nSn/nTi molar ratio exhibit a 1.84-fold improvement in photodegradation of MB arising from the enhanced light absorption ability, increased number of photogenerated electron–hole pairs, and prolonged charge carrier lifetime. In addition, the detailed mechanisms are also discussed in the present paper.


2017 ◽  
Vol 10 (04) ◽  
pp. 1750034 ◽  
Author(s):  
Guosong Wu ◽  
Qiuping Shen ◽  
Houlin Yu ◽  
Tingyu Zhao ◽  
Congda Lu ◽  
...  

The Cu2O/reduced graphene oxide (Cu2O/rGO) composites with effective crystallographic facet controlling of Cu2O crystals were fabricated through a simple one-step wet chemistry method. The crystallographic facet-dependent photocatalytic performance of Cu2O was confirmed, favoring the cuboctahedral Cu2O with {100} and {111} facets and a better photocatalytic activity when compared to cubic and octahedral ones. This was attributed to the slight difference of surface energy between {100} and {111} facets which served as a driving force to promote the separation of photogenerated electron–hole pairs. Moreover, the introduction of two-dimensional rGO sheets could accelerate the transfer of photogenerated electrons from Cu2O to rGO, which further promoted the separation of photogenerated electron–hole pairs and the degradation of methyl orange (MO) under visible-light irradiation. The cuboctahedral Cu2O/rGO composite exhibited a superb photocatalytic performance with the degradation percentage of MO about 97.6% after one periodic photocatalysis due to the synergistic effect of cuboctahedral Cu2O and rGO sheets, foreboding its potential application as photocatalyst.


NANO ◽  
2019 ◽  
Vol 14 (02) ◽  
pp. 1950015 ◽  
Author(s):  
Xin Gao ◽  
Changchang Ma ◽  
Wei Ma ◽  
Rongru Chen ◽  
Yang Liu ◽  
...  

A novel ternary Cu2O/BiVO4/RGO photocatalyst is successfully constructed by hydrothermal and evaporation-induced method, and it exhibits superior photocatalytic performance for degradation tetracycline (TC). Meanwhile, the visible light absorption range of composite photocatalyst is effectively broadened by the formation of heterojunction with narrow band gap semiconductor Cu2O. And the separation efficiency of the photogenerated electron–hole pairs is significantly enhanced by the synergistic effect of Cu2O and RGO. More importantly, the adsorption of TC by ternary Cu2O/BiVO4/RGO possesses high adsorption capacity, which is 23.73 times higher than that of pure BiVO4. Additionally, the possible reaction mechanism is clearly revealed by radical trapping experiment, electron spin-resonance (ESR) spectroscopy. This work provides a new insight to design a photocatalyst with excellent adsorption to remove organic contaminants in water.


CrystEngComm ◽  
2015 ◽  
Vol 17 (3) ◽  
pp. 569-576 ◽  
Author(s):  
Yin Peng ◽  
Qing-Guo Chen ◽  
Dan Wang ◽  
Hai-Yan Zhou ◽  
An-Wu Xu

A one-dimensional WO3–Bi2WO6 photocatalyst exhibits high photocatalytic activity for the degradation of rhodamine B (RhB) under solar light irradiation, which is attributed to the effective separation of photogenerated electron–hole pairs by the staggered band potentials between WO3 and Bi2WO6.


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