scholarly journals Photocatalytic Processes for Environmental Applications

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2080
Author(s):  
Olivier Monfort ◽  
Yanlin Wu
Keyword(s):  
Environmental Remediation ◽  
Heterogeneous Photocatalysis ◽  
Environmental Applications ◽  
Photocatalytic Processes

Photocatalysis, especially heterogeneous photocatalysis, is one of the most investigated processes for environmental remediation [...]

scholarly journals Shedding light on the nature of the catalytically active species in photocatalytic reactions using Bi2O3 semiconductor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Paola Riente ◽  
Mauro Fianchini ◽  
Patricia Llanes ◽  
Miquel A. Pericàs ◽  
Timothy Noël
Keyword(s):  
Experimental Studies ◽  
Heterogeneous Photocatalysis ◽  
Active Species ◽  
Organic Transformations ◽  
Alkyl Bromides ◽  
Catalytically Active ◽  
Visible Light Driven ◽  
Photocatalytic Reactions ◽  
Insight Into ◽  
Photocatalytic Processes

AbstractThe importance of discovering the true catalytically active species involved in photocatalytic systems allows for a better and more general understanding of photocatalytic processes, which eventually may help to improve their efficiency. Bi2O3 has been used as a heterogeneous photocatalyst and is able to catalyze several synthetically important visible-light-driven organic transformations. However, insight into the operative catalyst involved in the photocatalytic process is hitherto missing. Herein, we show through a combination of theoretical and experimental studies that the perceived heterogeneous photocatalysis with Bi2O3 in the presence of alkyl bromides involves a homogeneous BinBrm species, which is the true photocatalyst operative in the reaction. Hence, Bi2O3 can be regarded as a precatalyst which is slowly converted in an active homogeneous photocatalyst. This work can also be of importance to mechanistic studies involving other semiconductor-based photocatalytic processes.

scholarly journals Heterogeneous Photocatalysis Scalability for Environmental Remediation: Opportunities and Challenges

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1109 ◽  
Author(s):  
Sherif Younis ◽  
Ki-Hyun Kim
Keyword(s):  
Environmental Remediation ◽  
Scale Up ◽  
Pilot Scale ◽  
Heterogeneous Photocatalysis ◽  
Solar Irradiation ◽  
Practical Implementation ◽  
Feed Composition ◽  
Photocatalytic System ◽  
Environmental Treatment ◽  
Contemporary Perspective

Heterogeneous photocatalysis is an ecofriendly technique for purifying organic pollutants in environmental systems. While pilot-scale photoreactors have explored photocatalytic system upscalibility, their practical implementation is restricted for various reasons. These include feed composition alteration, complicated photoreactor designs, high operation and synthesis costs, photocatalyst poisoning, low quantum yield under solar irradiation, fast exciton recombination, and low reuse or regeneration capabilities. In this paper, we highlight the photocatalyst scalability challenges for real-world applications. We also provide an in-depth discussion on photocatalyst opportunities for effective air and water pollution control. Lastly, we offer a contemporary perspective on photocatalysis scale-up for the real environmental treatment.

3D Printing of Metal-Organic Frameworks for Clean Energy and Environmental Applications

2021 ◽  
Author(s):  
Eleanor Rose Kearns ◽  
Rohan Gillespie ◽  
Deanna Michelle D'Alessandro
Keyword(s):  
3D Printing ◽  
Environmental Remediation ◽  
Metal Organic Frameworks ◽  
Clean Energy ◽  
Environmental Applications ◽  
The World ◽  
Co2 Levels ◽  
Metal Organic

The world is facing a climate emergency: unchecked pollution coupled with rising CO2 levels is putting unprecedented strain on the planet’s ecosystems. Technologies for environmental remediation are thus becoming increasingly...

Titania-based heterogeneous photocatalysis. Materials, mechanistic issues, and implications for environmental remediation

2001 ◽  
Vol 73 (12) ◽  
pp. 1849-1860 ◽  
Author(s):  
Krishnan Rajeshwar ◽  
C. R. Chenthamarakshan ◽  
Scott Goeringer ◽  
Miljana Djukic
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Hexavalent Chromium ◽  
Environmental Remediation ◽  
Catalytic Properties ◽  
Heterogeneous Photocatalysis ◽  
The Other ◽  
Tio2 Surface ◽  
Tio2 Sample

Using hexavalent chromium [Cr(VI)] and methylene blue (MB) as model substrates, we discuss three aspects of TiO2-based heterogeneous photocatalysis. We show first that a given TiO2 sample may not be simultaneously optimal for photocatalytically driving the reduction of Cr(VI) and the oxidation of MB. We further show that a TiO2 sample that strongly adsorbs either of these substrates in the dark is not optimal as a photocatalyst. The other two aspects concern circumventing the rather poor surface catalytic properties and visible light photoresponse of TiO2, respectively. Strategies revolving around the visible light photoexcitation of the substrate itself and metal-modification of the TiO2 surface, are described as possible solutions.

Chitosan Based Nanocomposite Materials as Photocatalyst – A Review

2014 ◽  
Vol 781 ◽  
pp. 79-94 ◽  
Author(s):  
A. Nithya ◽  
Kandasamy Jothivenkatachalam ◽  
S. Prabhu ◽  
K. Jeganathan
Keyword(s):  
Catalytic Activity ◽  
Environmental Remediation ◽  
Low Cost ◽  
Nanocomposite Materials ◽  
Heterogeneous Photocatalysis ◽  
Organic Polymer ◽  
High Catalytic Activity ◽  
Environmental Application ◽  
Industrial Activities

Heterogeneous photocatalysis is a significant technology for environmental application. Moreover, immobilising an appropriate catalyst on the surface of a natural organic polymer presents a number of additional advantages including low-cost, high catalytic activity and extensive potential reuse for the application of pharmaceutical, biomedical and industrial activities. This review mainly focuses on the role of chitosan based material as photocatalyst on the environmental remediation.

scholarly journals Fabrication of Rh-doped TiO2 nanofibers for Visible Light Degradation of Rhodamine B

2011 ◽  
Vol 1352 ◽  
Author(s):  
Emilly A. Obuya ◽  
William Harrigan ◽  
Tim O’Brien ◽  
Dickson Andala ◽  
Eliud Mushibe ◽  
...  
Keyword(s):  
Visible Light ◽  
Rhodamine B ◽  
Environmental Remediation ◽  
Heterogeneous Catalysts ◽  
Low Cost ◽  
Organic Pollutant ◽  
Heterogeneous Photocatalysis ◽  
Tio2 Nanofibers ◽  
Visible Light Degradation ◽  
Surface Modified

ABSTRACTThe synthesis and application of environmentally benign, efficient and low cost heterogeneous catalysts is increasingly important for affordable and clean chemical technologies. Nanomaterials have been proposed to have new and exciting properties relative to their bulk counterparts due to the quantum level interactions that exist at nanoscale. These materials also offer enormous surface to volume ratios that would be invaluable in heterogeneous catalysis. Recent studies point at titanium dioxide nanomaterials as having strong potential to be applied in heterogeneous photocatalysis for environmental remediation and pollution control. This work reports the use of surface modified anatase TiO2 nanofibers with rhodium (Rh) nanoparticles in the photodegradation of rhodamine B (RH-B), an organic pollutant. The dimensions of TiO2 nanofibers were 150±50 nm in diameter and the size of the Rh nanoparticles was ~5 nm. The Rh-doped TiO2 catalyst exhibited an enhanced photocatalytic activity in photodegradation of rhodamine B under visible light irradiation, with 95 % degradation within 180 minutes reaction time. Undoped TiO2 did not show any notable phocatalytic activity under visible light.

scholarly journals Hierarchical electrospun nanofibers for energy harvesting, production and environmental remediation

2014 ◽  
Vol 7 (10) ◽  
pp. 3192-3222 ◽  
Author(s):  
Palaniswamy Suresh Kumar ◽  
Jayaraman Sundaramurthy ◽  
Subramanian Sundarrajan ◽  
Veluru Jagadeesh Babu ◽  
Gurdev Singh ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Environmental Remediation ◽  
Electrospun Nanofibers ◽  
Environmental Applications ◽  
Recent Developments

Recent developments in the synthesis of electrospun nanomaterials and their potential prospects in energy and environmental applications are discussed in detail.

scholarly journals Application of EPR Spectroscopy in TiO2 and Nb2O5 Photocatalysis

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1514
Author(s):  
Osama Al-Madanat ◽  
Barbara Nascimento Nunes ◽  
Yamen AlSalka ◽  
Amer Hakki ◽  
Mariano Curti ◽  
...  
Keyword(s):  
Epr Spectroscopy ◽  
Environmental Remediation ◽  
Deep Understanding ◽  
Heterogeneous Photocatalysis ◽  
Green Energy ◽  
Trap States ◽  
Photocatalytic Process ◽  
Experimental Conditions ◽  
Paramagnetic Resonance ◽  
Wide Range

The interaction of light with semiconducting materials becomes the center of a wide range of technologies, such as photocatalysis. This technology has recently attracted increasing attention due to its prospective uses in green energy and environmental remediation. The characterization of the electronic structure of the semiconductors is essential to a deep understanding of the photocatalytic process since they influence and govern the photocatalytic activity by the formation of reactive radical species. Electron paramagnetic resonance (EPR) spectroscopy is a unique analytical tool that can be employed to monitor the photoinduced phenomena occurring in the solid and liquid phases and provides precise insights into the dynamic and reactivity of the photocatalyst under different experimental conditions. This review focus on the application of EPR in the observation of paramagnetic centers formed upon irradiation of titanium dioxide and niobium oxide photocatalysts. TiO2 and Nb2O5 are very well-known semiconductors that have been widely used for photocatalytic applications. A large number of experimental results on both materials offer a reliable platform to illustrate the contribution of the EPR studies on heterogeneous photocatalysis, particularly in monitoring the photogenerated charge carriers, trap states, and surface charge transfer steps. A detailed overview of EPR-spin trapping techniques in mechanistic studies to follow the nature of the photogenerated species in suspension during the photocatalytic process is presented. The role of the electron donors or the electron acceptors and their effect on the photocatalytic process in the solid or the liquid phase are highlighted.

scholarly journals Hierarchical TiO2 Layers Prepared by Plasma Jets

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3254
Author(s):  
Radek Zouzelka ◽  
Jiri Olejnicek ◽  
Petra Ksirova ◽  
Zdenek Hubicka ◽  
Jan Duchon ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Advanced Oxidation Processes ◽  
Reaction Rate ◽  
Photocatalytic Performance ◽  
Scale Up ◽  
Textural Properties ◽  
Heterogeneous Photocatalysis ◽  
Reaction Rate Constant ◽  
Plasma Jets ◽  
Physico Chemical

Heterogeneous photocatalysis of TiO2 is one of the most efficient advanced oxidation processes for water and air purification. Here, we prepared hierarchical TiO2 layers (Spikelets) by hollow-cathode discharge sputtering and tested their photocatalytic performance in the abatement of inorganic (NO, NO2) and organic (4-chlorophenol) pollutant dispersed in air and water, respectively. The structural-textural properties of the photocatalysts were determined via variety of physico-chemical techniques (XRD, Raman spectroscopy, SEM, FE-SEM. DF-TEM, EDAX and DC measurements). The photocatalysis was carried out under conditions similar to real environment conditions. Although the abatement of NO and NO2 was comparable with that of industrial benchmark Aeroxide® TiO2 P25, the formation of harmful nitrous acid (HONO) product on the Spikelet TiO2 layers was suppressed. Similarly, in the decontamination of water by organics, the mineralization of 4-chlorophenol on Spikelet layers was interestingly the same, although their reaction rate constant was three-times lower. The possible explanation may be the more than half-magnitude order higher external quantum efficacy (EQE) compared to that of the reference TiO2 P25 layer. Therefore, such favorable kinetics and reaction selectivity, together with feasible scale-up, make the hierarchical TiO2 layers very promising photocatalyst which can be used for environmental remediation.

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