scholarly journals Microfluidic Reactors for Plasmonic Photocatalysis Using Gold Nanoparticles

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 869 ◽  
Author(s):  
Huaping Jia ◽  
Yat Lam Wong ◽  
Aoqun Jian ◽  
Chi Chung Tsoi ◽  
Meiling Wang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Visible Light ◽  
Tio2 Film ◽  
Low Cost ◽  
Field Tests ◽  
Reaction Rate Constant ◽  
Strong Absorption ◽  
Electron Hole ◽  
Protective Function ◽  
Potential Applications

This work reports a microfluidic reactor that utilizes gold nanoparticles (AuNPs) for the highly efficient photocatalytic degradation of organic pollutants under visible light. The bottom of microchamber has a TiO2 film covering a layer of AuNPs (namely, TiO2/AuNP film) deposited on the F-doped SnO2 (FTO) substrate. The rough surface of FTO helps to increase the surface area and the AuNPs enables the strong absorption of visible light to excite electron/hole pairs, which are then transferred to the TiO2 film for photodegradation. The TiO2 film also isolates the AuNPs from the solution to avoid detachment and photocorrosion. Experiments show that the TiO2/AuNP film has a strong absorption over 400–800 nm and enhances the reaction rate constant by 13 times with respect to the bare TiO2 film for the photodegradation of methylene blue. In addition, the TiO2/AuNP microreactor exhibits a negligible reduction of photoactivity after five cycles of repeated tests, which verifies the protective function of the TiO2 layer. This plasmonic photocatalytic microreactor draws the strengths of microfluidics and plasmonics, and may find potential applications in continuous photocatalytic water treatment and photosynthesis. The fabrication of the microreactor uses manual operation and requires no photolithography, making it simple, easy, and of low cost for real laboratory and field tests.

scholarly journals Enhanced Visible Light Photocatalytic Reduction of Cr(VI) over a Novel Square Nanotube Poly(Triazine Imide)/TiO2 Heterojunction

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 55 ◽  
Author(s):  
Xin Yan ◽  
Guotao Ning ◽  
Peng Zhao
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Low Cost ◽  
High Specific Surface Area ◽  
Electron Hole ◽  
Graphite Phase ◽  
Reduction Efficiency ◽  
The One

Hexavalent chromium Cr(VI) pollution makes has a harmful impact on human health and the ecological environment. Photocatalysis reduction technology exhibits low energy consumption, high reduction efficiency and stable performance, and is playing an increasingly important role in chromium pollution control. Graphite-phase carbon nitride has been used to reduce Cr(VI) to the less harmful Cr(III) due to its visible light catalytic activity, chemical stability and low cost. However, it has a low specific surface area and fast recombination of electron–hole pairs, which severely restrict its practical application. In this work, a TiO2-modified poly(triazine imide) (PTI) square nanotube was prepared by the one-step molten salts method. The results showed the PTI had a square hollow nanotube morphology, with an about 100–1000 nm width and 60–70 nm thickness. During the formation of the PTI square tube, TiO2 nanoparticles adhere to the surface of the square tube wall by strong adsorption, and eventually form a PTI/TiO2 heterojunction. The PTI/TiO2-7 wt% heterojunction exhibited very good Cr(VI) reduction efficiency within 120 min. The enhanced photocatalytic activity was mainly attributed to the efficient separation and transport of photo-induced electron–hole pairs and the high specific surface area in the heterojunction structure.

scholarly journals Advances in metal-based vanadate compound photocatalysts: synthesis, properties and applications

2021 ◽  
Vol 1 (3) ◽  
pp. 151-168
Author(s):  
Asieh Akhoondi ◽  
Usisipho Feleni ◽  
Bhaskar Bethi ◽  
Azeez Olayiwola Idris ◽  
Akbar Hojjati-Najafabadi
Keyword(s):  
Visible Light ◽  
Low Cost ◽  
Synthesis Temperature ◽  
Solution Ph ◽  
Electron Hole ◽  
Preparation Methods ◽  
Ongoing Research ◽  
Synthesis Properties ◽  
Electron Hole Pair ◽  
Temperature Solution

Among the ongoing research on photocatalysis under visible-light, it has been shown that doped or hybrid catalysts are more active than a single catalyst alone. However, problems including visible light absorption, a low quantity of energetic sites on surfaces, and rapid recombination of the photo-electron hole pair produced by light have prohibited photocatalysts from being used in a practical and widespread manner. To overcome these problems, synthesis of nanostructure hybrid catalyst using several methods has attracted much attention. Several procedures have been suggested for the preparation of photocatalysts with the desired structure and morphology. Preparation methods similar to partial modification may lead to diverse structures and qualities. In this regard, the development of efficient, low-cost photocatalysts and rapid synthesis is the most important issues that should be considered. This review discusses various methods and mechanisms that work with the modification of vanadium compounds as photocatalysts to progress their photocatalytic efficiency. In addition, the effects of synthesis temperature, solution pH and concentration on the photocatalytic performance are also described in detail.

Ti3C2-MXene/Bismuth Ferrite Nanohybrids for Efficient Degradation of Organic Dye and Colorless Pollutant

2019 ◽  
Author(s):  
Ayesha Tariq ◽  
M. Abdullah Iqbal ◽  
S. Irfan Ali ◽  
Muhammad Z. Iqbal ◽  
Deji Akinwande ◽  
...  
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
Bismuth Ferrite ◽  
Organic Dye ◽  
Two Dimensional ◽  
Electron Hole ◽  
Photocatalytic Application ◽  
Electron Hole Pair ◽  
Pair Generation ◽  
Photocatalytic Applications

<p>Nanohybrids, made up of Bismuth ferrites/Carbon allotropes, are extensively used in photocatalytic applications nowadays. Our work proposes a nanohybrid system composed of Bismuth ferrite nanoparticles with two-dimensional (2D) MXene sheets namely, the BiFeO<sub>3</sub> (BFO)/Ti<sub>3</sub>C<sub>2</sub> (MXene) nanohybrid for enhanced photocatalytic activity. We have fabricated the BFO/MXene nanohybrid using simple and low cost double solvent solvothermal method. The SEM and TEM images show that the BFO nanoparticles were attached onto the MXene surface and in the inter-layers of two-dimensional (2D) MXene sheets. The photocatalytic application is tested for the visible light irradiation which showed the highest efficiency among all pure-BFO based photocatalysts, i.e. 100% degradation in 42 min for organic dye (Congo Red) and colorless aqueous pollutant (acetophenone) in 150 min, respectively. The present BFO-based hybrid system exhibited the large surface area of 147 m<sup>2</sup>g<sup>-1</sup>measured via Brunauer-Emmett-Teller (BET) sorption-desorption technique, and is found to be largest among BFO and its derivatives. Also, the photoluminescence (PL) spectra indicate large electron-hole pair generation. Fast and efficient degradation of organic molecules is supported by both factors; larger surface area and lower electron-hole recombination rate. The BFO/MXene nanohybrid presented here is a highly efficient photocatalyst compared to other nanostructures based on pure BiFeO<sub>3</sub> which makes it a promising candidate for many future applications.</p>

scholarly journals Construction of Ag3PO4/SnO2 Heterojunction on Carbon Cloth with Enhanced Visible Light Photocatalytic Degradation

2020 ◽  
Vol 10 (9) ◽  
pp. 3238
Author(s):  
Min Liu ◽  
Guangxin Wang ◽  
Panpan Xu ◽  
Yanfeng Zhu ◽  
Wuhui Li
Keyword(s):  
Visible Light ◽  
Photocatalytic Performance ◽  
Separation Efficiency ◽  
Photogenerated Electron ◽  
Carbon Cloth ◽  
Electron Hole ◽  
Step Process ◽  
Photogenerated Electrons ◽  
Rapid Transfer ◽  
Visible Light Photocatalytic

In this study, the Ag3PO4/SnO2 heterojunction on carbon cloth (Ag3PO4/SnO2/CC) was successfully fabricated via a facile two-step process. The results showed that the Ag3PO4/SnO2/CC heterojunction exhibited a remarkable photocatalytic performance for the degradation of Rhodamine B (RhB) and methylene blue (MB), under visible light irradiation. The calculated k values for the degradation of RhB and MB over Ag3PO4/SnO2/CC are 0.04716 min−1 and 0.04916 min−1, which are higher than those calculated for the reactions over Ag3PO4/SnO2, Ag3PO4/CC and SnO2/CC, respectively. The enhanced photocatalytic activity could mainly be attributed to the improved separation efficiency of photogenerated electron-hole pairs, after the formation of the Ag3PO4/SnO2/CC heterojunction. Moreover, carbon cloth with a large specific surface area and excellent conductivity was used as the substrate, which helped to increase the contact area of dye solution with photocatalysts and the rapid transfer of photogenerated electrons. Notably, when compared with the powder catalyst, the catalysts supported on carbon cloth are easier to quickly recycle from the pollutant solution, thereby reducing the probability of recontamination.

scholarly journals Enhanced Visible-Light Photocatalytic Performance of SAPO-5-Based g-C3N4 Composite for Rhodamine B (RhB) Degradation

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3948
Author(s):  
Lingfang Qiu ◽  
Zhiwei Zhou ◽  
Mengfan Ma ◽  
Ping Li ◽  
Jinyong Lu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Redox Reactions ◽  
Photocatalytic Performance ◽  
Dye Degradation ◽  
Thermal Polymerization ◽  
Light Illumination ◽  
Electron Hole ◽  
Visible Light Illumination ◽  
Visible Light Photocatalytic

Novel visible-light responded aluminosilicophosphate-5 (SAPO-5)/g-C3N4 composite has been easily constructed by thermal polymerization for the mixture of SAPO-5, NH4Cl, and dicyandiamide. The photocatalytic activity of SAPO-5/g-C3N4 is evaluated by degrading RhB (30 mg/L) under visible light illumination (λ > 420 nm). The effects of SAPO-5 incorporation proportion and initial RhB concentration on the photocatalytic performance have been discussed in detail. The optimized SAPO-5/g-C3N4 composite shows promising degradation efficiency which is 40.6% higher than that of pure g-C3N4. The degradation rate improves from 0.007 min−1 to 0.022 min−1, which is a comparable photocatalytic performance compared with other g-C3N4-based heterojunctions for dye degradation. The migration of photo-induced electrons from g-C3N4 to the Al site of SAPO-5 should promote the photo-induced electron-hole pairs separation rate of g-C3N4 efficiently. Furthermore, the redox reactions for RhB degradation occur on the photo-induced holes in the g-C3N4 and Al sites in SAPO-5, respectively. This achievement not only improves the photocatalytic activity of g-C3N4 efficiently, but also broadens the application of SAPOs in the photocatalytic field.

scholarly journals Preparation and Photocatalytic Performance for Degradation of Rhodamine B of AgPt/Bi4Ti3O12 Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2206
Author(s):  
Gaoqian Yuan ◽  
Gen Zhang ◽  
Kezhuo Li ◽  
Faliang Li ◽  
Yunbo Cao ◽  
...  
Keyword(s):  
Visible Light ◽  
Noble Metal ◽  
Rhodamine B ◽  
Photocatalytic Performance ◽  
Bimetallic Nanoparticles ◽  
Resonance Effect ◽  
Visible Region ◽  
Photogenerated Electron ◽  
Pt Nanoparticles ◽  
Electron Hole

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.

scholarly journals Preparation and photocatalytic performance of metallic Nb0.9Ta0.1S2/2D-C3N4 composite

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Hanxiang Chen ◽  
Jianjian Yi ◽  
Zhao Mo ◽  
Yanhua Song ◽  
Wenshu Yang ◽  
...  
Keyword(s):  
Separation Efficiency ◽  
Low Cost ◽  
Metal Sulfide ◽  
Electron Hole ◽  
Practical Applications ◽  
Energy And Environment ◽  
Photocatalytic Application ◽  
Light Utilization ◽  
Ternary Metal ◽  
Key Issues

Abstract Photocatalysis technology has potential application in the field of energy and environment. How to expand visible light utilization and promote the separation efficiency of the carriers are the key issues for the high active photocatalysts preparation and future practical applications. In this work, a ternary metal sulfide Nb0.9Ta0.1S2 was prepared and used as an electron collector in the photocatalytic application. As a result, the generated electrons are quickly transferred to the surface of the composite to participate in the reaction. It was demonstrated that the photocatalytic activity of 2D-C3N4 was enhanced after the modification of Nb0.9Ta0.1S2. The Nb0.9Ta0.1S2/2D-C3N4 composite material was synthesized by solvothermal method. The composition of 5% Nb0.9Ta0.1S2/2D-C3N4 showed the highest H2 evolution rate of 1961.6 μmolg−1h−1, which was 6.6 times that of 2D-C3N4. The 15% Nb0.9Ta0.1S2/2D-C3N4 exhibited the best activity in Rhodamine B degradation rate of 97% in 2 h, which is 50% higher than that of 2D-C3N4. Nb0.9Ta0.1S2/2D-C3N4 can be used as electron trap to promote the effective separation of electron–hole pairs. This work provides benchmarks in exploring low-cost and efficient cocatalyst.

Solution Processed Sb2S3-based Photocathode with Enhanced Photocatalytic Performance via Constructing Ultrathin TiO2 Overlayer and Noble Metal Modification

2021 ◽  
Author(s):  
Yanwen Wang ◽  
Rong Liang ◽  
Chao Qin ◽  
Lei Ren ◽  
Zhizhen Ye ◽  
...  
Keyword(s):  
Visible Light ◽  
Noble Metal ◽  
Photocatalytic Performance ◽  
Low Cost ◽  
Light Response ◽  
Solution Processed ◽  
Antimony Sulfide ◽  
Visible Light Response ◽  
Absorbing Material

Antimony sulfide (Sb2S3) is a light absorbing material with strong visible light response, which is suitable for efficient and low-cost photoelectrodes. Nano-structured films have unique advantages in constructing photoelectrodes due...

scholarly journals Visualization of Surface Acoustic Waves in Thin Liquid Films

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
R. W. Rambach ◽  
J. Taiber ◽  
C. M. L. Scheck ◽  
C. Meyer ◽  
J. Reboud ◽  
...  
Keyword(s):  
Liquid Film ◽  
Acoustic Waves ◽  
Low Cost ◽  
Thin Liquid Film ◽  
Surface Acoustic Waves ◽  
Liquid Films ◽  
Theoretical Description ◽  
Propagation Path ◽  
Microfluidic Channels ◽  
Potential Applications

Abstract We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect.

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