scholarly journals Fabrication of La2O3/g-C3N4 Heterojunction with Enhanced Photocatalytic Performance of Tetracycline Hydrochloride

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1349
Author(s):  
Zhengru Zhu ◽  
Haiwen Xia ◽  
Rina Wu ◽  
Yongqiang Cao ◽  
Hong Li
Keyword(s):  
Hydroxyl Radicals ◽  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Superoxide Radical ◽  
Active Species ◽  
Tetracycline Hydrochloride ◽  
Radical Anions ◽  
Photocatalytic Process ◽  
Composite Photocatalysts ◽  
Ultrasound Assisted

In this study, La2O3/g-C3N4 heterojunction photocatalysts doped with different dosages of La2O3 were constructed by a facile ultrasound-assisted calcination approach. The as-prepared photocatalysts were characterized by XRD, FTIR, FESEM, TEM, XPS, PL and DRS to verify the composite photocatalysts’ purity and to investigate their structural, morphological and elemental composition, and their energy band. According to the results, a type of pure rod–sheet-shaped, heterostructured nanoparticle was successfully obtained. Decorated with 10% La2O3, 2 g/L of the composite sample had a 93% degradation rate for 20 mg/L tetracycline hydrochloride within 2 h under visible light at a pH of 7. After four successive photocatalytic runs, satisfactory stability and reusability was exhibited, with 70% of the tetracycline hydrochloride being removed in the final experiment. Electrons (e−), photogenerated holes (h+), superoxide radical anions (O2−) and hydroxyl radicals (OH) were the fundamental active species during the photocatalytic process and were investigated via quenching experiments. Furthermore, possible photocatalytic mechanisms were analyzed in this work.

Microwave-Assisted Fabrication of Recyclable CdS/Fe3O4/rGO Photocatalysts to Improve the Photocatalytic Performance Under Visible Light

NANO ◽  
2016 ◽  
Vol 11 (11) ◽  
pp. 1650129 ◽  
Author(s):  
Xinlin Liu ◽  
Yingying Qin ◽  
Mingjun Zhou ◽  
Yongsheng Yan
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Visible Light ◽  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Active Species ◽  
Microwave Method ◽  
Composite Photocatalyst ◽  
Microwave Assisted

A unique CdS/Fe3O4/rGO composite photocatalyst is successfully synthesized by the microwave method. It displays promising photocatalytic activity towards the photo-degrading of tetracycline (TC) in aqueous solution, the degradation rate of TC is 69% with adding 0.1[Formula: see text]g CdS/Fe3O4/rGO photocatalyst into 20[Formula: see text]mg/L tetracycline for 2[Formula: see text]h under visible light irradiation. Furthermore, the mechanism was systematically investigated by active species trapping experiment. It can be known that [Formula: see text] the major active species in the photodegradation process and the possible process of charge transfer for CdS/Fe3O4/rGO was proposed based on the experimental results. The as-prepared samples were carefully evaluated by XRD, TEM, XPS, VSM, PL spectra, Raman spectrometer.

scholarly journals Electrospinning preparation of g-C3N4/Nb2O5 nanofibers heterojunction for enhanced photocatalytic degradation of organic pollutants in water

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lu Wang ◽  
Ya Li ◽  
Pingfang Han
Keyword(s):  
Organic Pollutants ◽  
Radical Anion ◽  
Carbon Nitride ◽  
Superoxide Radical ◽  
Active Species ◽  
Photocatalytic Process ◽  
Photoluminescence Spectra ◽  
Calcination Process ◽  
Superoxide Radical Anion ◽  
Transient Photocurrent

AbstractIn this study, graphitic carbon nitride (g-C3N4) and niobium pentoxide nanofibers (Nb2O5 NFs) heterojunction was prepared by means of a direct electrospinning approach combined with calcination process. The characterizations confirmed a well-defined morphology of the g-C3N4/Nb2O5 heterojunction in which Nb2O5 NFs were tightly attached onto g-C3N4 nanosheets. Compared to pure g-C3N4 and Nb2O5 NFs, the as-prepared g-C3N4/Nb2O5 heterojunction exhibited remarkably enhanced photocatalytic activity for degradation of rhodamine B and phenol under visible light irradiation. The enhanced catalytic activity was attributed predominantly to the synergistic effect between g-C3N4 sheets and Nb2O5 NFs, which promoted the transferring of carriers and prohibited their recombination, confirmed by the measurement of transient photocurrent responses and photoluminescence spectra. In addition, the active species trapping experiments indicated that superoxide radical anion (·O2–) and hole (h+) were the major active species contributing to the photocatalytic process. With its high efficacy and ease of preparation, g-C3N4/Nb2O5 heterojunction has great potentials for applications in treatment of organic pollutants and conversion of solar energy.

scholarly journals Synthesis of Novel Ternary Dual Z-scheme AgBr/LaNiO3/g-C3N4 Composite with Boosted Visible-Light Photodegradation of Norfloxacin

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3706 ◽  
Author(s):  
Junjiao Zhang ◽  
Zhengru Zhu ◽  
Junchao Jiang ◽  
Hong Li
Keyword(s):  
Photocatalytic Performance ◽  
Superoxide Radical ◽  
Reaction System ◽  
Active Species ◽  
Absorption Capacity ◽  
Photocatalytic Reaction ◽  
Superoxide Radical Anion ◽  
Photodegradation Rate ◽  
First Time ◽  
Semiconductor Photocatalyst

Promoting the separation of photogenerated charges and enhanced optical absorption capacity is the main means to modify photocatalytic capacities to advance semiconductor photocatalyst applications. For the first time, a novel ternary photocatalyst for dual Z-scheme system AgBr/LaNiO3/g-C3N4 (ALG) was prepared via a modest ultrasound-assisted hydrothermal method. The results indicated that LaNiO3 nanoballs and AgBr nanoparticles were successfully grown on the surface of g-C3N4 nanosheets. A dual Z-scheme photocatalytic reaction system could be constructed based on the energy band matching within AgBr, LaNiO3 and g-C3N4. Metallic Ag during the photocatalytic reaction process acted as the active electrons transfer center to enhance the photocatalytic charge pairs separation. The chemical composition of ALG was optimized and composites with 3% AgBr, 30% LaNiO3 and 100% g-C3N4 which was noted as 3-ALG displayed the best photocatalytic performance. A total of 92% of norfloxacin (NOR) was photodegraded within two hours over ALG and the photodegradation rate remained >90% after six cycles. The main active species during the degradation course were photogenerated holes, superoxide radical anion and hydroxyl radical. A possible mechanism was proposed based on the synergetic effects within AgBr, LaNiO3 and g-C3N4. This work would offer a credible theoretical basis for the application of dual Z-scheme photocatalysts in environment restoration.

Photocatalytic degradation of ofloxacin by ZnO/CsxWO3 composite synthesized by two-step method: A kinetic study

2019 ◽  
Vol 12 (05) ◽  
pp. 1950068 ◽  
Author(s):  
Wenwen Ning ◽  
Zhihuan Zhao ◽  
Honghong Chang ◽  
Zhanyong Gu ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Solvothermal Method ◽  
Active Species ◽  
Step Method ◽  
Full Spectrum ◽  
First Order ◽  
First Order Kinetics ◽  
Photogenerated Electrons ◽  
Prepared Composite

The composite of ZnO/CsxWO3 with heterojunction was prepared by a two-step solvothermal method and the degradation of ofloxacin solution under full-spectrum light irradiation was carried out to evaluate the performance. The composites were characterized by XRD, SEM, EDS and UV-Vis-NIR reflectance. The result shows that the prepared composite has an ideal optical absorption in the spectral region of 200–2500[Formula: see text]nm and higher photocatalytic performance compared with ZnO and CsxWO3. Moreover, [Formula: see text], [Formula: see text]OH and [Formula: see text][Formula: see text] radicals are determined to be the active species. It is suggested that the heterojunction between ZnO and CsxWO3 for ZnO/CsxWO3 composite is important for improving the charge separation and thus restraining the recombination of photogenerated electrons and holes. Photodegradation of ofloxacin catalyzed by ZnO/CsxWO3 followed the first-order kinetics and the degradation rate of ZnO/2CsxWO3 was about two times higher than those of CsxWO3 and ZnO.

scholarly journals The Effect of Nitrogen-Doped ATO Nanotubes on Radical Multiplication of Buffer Media by Visible Light Photocatalysis Rather UV

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Kan-Hung Hu ◽  
Shing-Hoa Wang ◽  
Todd Hsu ◽  
Chien-Chon Chen ◽  
Tai-Yuan Lin ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Free Radical ◽  
Visible Light ◽  
Hydroxyl Radicals ◽  
Superoxide Radical ◽  
Uv Light ◽  
Visible Light Photocatalysis ◽  
Radical Anions ◽  
Buffer Solution ◽  
Nitrogen Doped

The use of TiO2in photodynamic therapy for the treatment of cancer has generally been studied in cultured cancer cells in serum-containing RPMI 1640 medium under visible light application rather than ultraviolet (UV) light. An ordered channel array of N-doped anodic titanium dioxide (ATO) has been successfully made for visible light application. ATO nanotubes in the anatase form with a length of 10μm are more effective than nanotubes of 1.8 μm in length as a photocatalyst for radical multiplication in buffer solution by generating hydroxyl radicals and superoxide radical anions under UV-A exposure. Only the N-doped ATO is applicable to visible light photocatalysis for radical multiplication in RPMI1640+1% FBS and acrylamide, a free radical carrier.

Enhancement of hydroxyl radical generation by phenols and their reaction intermediates during ozonation

1998 ◽  
Vol 38 (6) ◽  
pp. 147-154 ◽  
Author(s):  
Hideo Utsumi ◽  
Sang-Kuk Han ◽  
Kazuhiro Ichikawa
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Spin Trapping ◽  
Active Species ◽  
Generation Rate ◽  
Peak Height Ratio ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Phenol Derivatives ◽  
Semiquinone Radicals

Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 X 10-6M of DMPO-OH, indicating that 1.4% of •OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance •OH generation during ozonation of water. Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.

scholarly journals ZnCDs/ZnO@ZIF-8 Zeolite Composites for the Photocatalytic Degradation of Tetracycline

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 934
Author(s):  
Yong Cheng ◽  
Xiuxiu Wang ◽  
Yu Mei ◽  
Dan Wang ◽  
Changchun Ji
Keyword(s):  
Catalytic Activity ◽  
Photocatalytic Degradation ◽  
Photocatalytic Performance ◽  
Active Species ◽  
Degradation Efficiency ◽  
Experimental Result ◽  
Porous Nanostructure ◽  
Resultant Material

Considering the photocatalytic performance of CDs, ZnO, and the unique porous nanostructure and stability of ZIF-8, we prepared ZnCDs/ZnO@ZIF-8 zeolite composites. The resultant material represented an enhanced ability for the photodegradation of TC compared with that of ZnCDs and ZnO. The photocatalytic degradation efficiency reached over 85%. The catalytic activity of the composites was maintained after four cycles. The experimental result indicated that ×O2 radical was the active species in the reaction.

Enhanced Photocatalytic Performance of Sn6SiO8 Nanoparticles and Their Reduced Graphene Oxide (rGO) Nanocomposite

2020 ◽  
Vol 20 (9) ◽  
pp. 5426-5432
Author(s):  
G. Gnanamoorthy ◽  
M. Muthukumaran ◽  
P. Varun Prasath ◽  
V. Karthikeyan ◽  
V. Narayanan ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Performance ◽  
Separation Efficiency ◽  
Dye Degradation ◽  
Hexagonal Phase ◽  
Active Species ◽  
Organic Chemical ◽  
Light Illumination ◽  
Sem Images ◽  
Radical Trapping

Photocatalysts provide excellent potential for the full removal of organic chemical pollutants as an environmentally friendly technology. It has been noted that under UV-visible light irradiation, nanostructured semiconductor metal oxides photocatalysts can degrade different organic pollutants. The Sn6SiO8/rGO nanocomposite was synthesized by a hydrothermal method. The Sn6SiO8 nanoparticles hexagonal phase was confirmed by XRD and functional groups were analyzed by FT-IR spectroscopy. The bandgap of Sn6SiO8 nanoparticles (NPs) and Sn6SiO8/GO composites were found to be 2.7 eV and 2.5 eV, respectively. SEM images of samples showed that the flakes like morphology. This Sn6SiO8/rGO nanocomposite was testing for photocatalytic dye degradation of MG under visible light illumination and excellent response for the catalysts. The enhancement of photocatalytic performance was mainly attributed to the increased light absorption, charge separation efficiency and specific surface area, proved by UV-vis DRS. Further, the radical trapping experiments revealed that holes (h+) and superoxide radicals (·O−2) were the main active species for the degradation of MG, and a possible photocatalytic mechanism was discussed.

The Study on the Influential Factors of Photocatalytic Performance of Eosin-Sensitized TiO2 Nanoparticles

2013 ◽  
Vol 827 ◽  
pp. 3-7
Author(s):  
Shun Jiang He ◽  
Xue Yan Du ◽  
Qiao Wang ◽  
Jing Xu
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Photocatalytic Degradation ◽  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Influential Factors ◽  
Sunlight Irradiation ◽  
Sensitization Time

The photocatalytic activity of eosin-sensitized TiO2 nanoparticles on photocatalytic degradation rate (PDR) of methyl orange under sunlight irradiation was studied. The influential factors on the degradation, such as eosin concentration, TiO2 dosage, sensitization time and sensitization temperature were also investigated. The results show that: The performance of TiO2 nanoparticles for PDR of methyl orange has been improved obviously for eosin sensitizing. The PDR of methyl orange reached 45.28% under the conditions of eosin concentration of 20mg/L, TiO2 dosage of 0.5000g/L, sensitization time of 24h and sensitization temperature of 20°C.

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