Theoretical Concepts of Photocatalysis

Theoretical Concepts ofenvironmental-related offer a systematic overview of photocatalysis while also exploring the theory and experimental studies of charge carrier dynamics. Introducing the fundamental concepts of photocatalytic reactions involving different types of photocatalysts for various applications, including the treatment of water and air, in food packaging, and in the biomedical and medical fields, the book shows different classes of photocatalysts for novel energy and environmental related applications. In addition, significant advantages, such as its low cost, high efficiency, harmlessness, and stability are discussed alongside future perspectives and challenges related to photocatalysis. Focusing on nanostructure control, synthesis methods, activity enhancement strategies, environmental applications, and perspectives of semiconductor-based nanostructures, this book offers guidelines for designing new semiconductor-based photocatalysts with low cost and high efficiency to meet the demands of the efficient utilization of solar energy in the area of energy production and environment remediation. https://www.sciencedirect.com/book/9780323951913/theoretical-concepts-of-photocatalysis#book-description</p

Environmentally Sustainable Fabrication of Ag@g‑C3N4 Nanostructures and Their Multifunctional Efficacy as Antibacterial Agents and Photocatalysts

<div>Noble-metal silver (Ag) nanoparticles (NPs) anchored/decorated onto polymeric graphitic carbon nitride (g-C3N4) as nanostructures (NSs) were prepared using</div><div>modest and environment-friendly synthesis method with a developed-single-strain biofilm as a reducing implement. The as-fabricated NSs were characterized using standard</div><div>characterization techniques. The nanosized and uniform AgNPs were well deposited onto the sheet-like matrix of g-C3N4 and exhibited good antimicrobial activity and superior</div><div>photodegradation of dyes methylene blue (MB) and rhodamine B (RhB) dyes under visible-light illumination. The Ag@g-C3N4 NSs exhibited active and effective bactericidal</div><div>performance and a survival test in counter to Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The as-fabricated NSs also exhibited superior visible-light</div><div>photodegradation of MB and RhB in much less time as compared to other reports. Ag@g-C3N4 NSs (3 mM) showed superior photocatalytic measurements under visible-light irradiation: ∼100% MB degradation and ∼89% of RhB degradation in 210 and 250 min, respectively. The obtained results indicate that the AgNPs were well deposited onto the g-C3N4 structure, which decreases the charge recombination rate of photogenerated electrons and holes and extends the performance of pure g-C3N4 under visible light. In conclusion, the as-fabricated Ag@g-C3N4 NSs are keen nanostructured materials that can be applied as antimicrobial materials and visible-light-induced photocatalysts.</div

Recent progress of metal–graphene

<div>Metal–graphene nanostructures (NSs) as photocatalysts, prepared using simple and scalable synthesis</div><div>methods, are gaining heightened attention as novel materials for water treatment and environmental</div><div>remediation applications. Graphene, the unique few layers sheet-like arrangement of sp2 hybridized</div><div>carbon atoms, has an inimitable two-dimensional (2D) structure. The material is highly conductive, has</div><div>high electron mobility and an extremely high surface area, and can be produced on a large scale at low</div><div>cost. Accordingly, it has been considered as an essential base component for producing various metalbased</div><div>NSs. In particular, metal-graphene NSs as photocatalysts have attracted considerable attention because of their special surface plasmon resonance (SPR) effect that can improve their performance for the removal of toxic dyes and other pollutants. This review summarizes the recent and advanced progress for the easy fabrication and design of graphene-based NSs as photocatalysts, as a novel tool, using a range of approaches, including green and biogenic approaches.</div

Ce3+-ion-induced visible-light photocatalytic degradation and electrochemical activity of ZnO/CeO2 nanocomposite

<div>In this study, pure ZnO, CeO2 and ZnO/CeO2 nanocomposites were synthesized using a thermal</div><div>decomposition method and subsequently characterized using different standard techniques. High resolution X-ray photoelectron spectroscopy measurements confirmed the oxidation states and presence of Zn2+, Ce4+, Ce3+ and different bonded oxygen species in the nanocomposites. The prepared pure ZnO and CeO2 as well as the ZnO/CeO2 nanocomposites with various proportions of ZnO and</div><div>CeO2 were tested for photocatalytic degradation of methyl orange, methylene blue and phenol under visible-light irradiation. The optimized and highly efficient ZnO/CeO2 (90:10) nanocomposite exhibited enhanced photocatalytic degradation performance for the degradation of methyl orange, methylene blue, and phenol as well as industrial textile effluent compared to ZnO, CeO2 and the other</div><div>investigated nanocomposites. Moreover, the recycling results demonstrate that the ZnO/CeO2 (90:10)</div><div>nanocomposite exhibited good stability and long-term durability. Furthermore, the prepared ZnO/CeO2</div><div>nanocomposites were used for the electrochemical detection of uric acid and ascorbic acid. The ZnO/CeO2 (90:10) nanocomposite also demonstrated the best detection, sensitivity and performance among the investigated materials in this application. These findings suggest that the synthesized ZnO/CeO2 (90:10) nanocomposite could be effectively used in various applications.</div

Biogenic fabrication of Au@CeO2 nanocomposite

Biogenic fabrication of Au@CeO2 nanocomposit

Au@TiO2 nanocomposites for the catalytic degradation of methyl orange and methylene blue: An electron relay effect

<div>Au@TiO2 nanocomposites were used for the catalytic degradation of methyl orange and methylene blue</div><div>by NaBH4. A detail pathway for step by step reduction, oxidation and complete mineralization of intermediates into the respective end-products was established by UV–vis spectroscopy, chemical oxygen demand, ion chromatography and cyclic voltammetry (CV). CV studies confirmed that the dyes were reduced and oxidized to the end-products by NaBH4 in the presence of Au@TiO2 nanocomposites and O2 , OH and HO2</div><div> radicals generated in situ. Results suggest that Au@TiO2 nanocomposites not only assist in the decolorization of dyes, but also promote their complete mineralization into harmless endproducts.</div

Fungi-assisted silver nanoparticle synthesis and their applications

Nanotechnology is a rapidly developing field because of its wide range of applications in science, nanoscience and biotechnology. Nanobiotechnology deals with nanomaterials synthesised or modified using biotechnology. Fungi are used to synthesise metal nanoparticles and they have vast applications in wound healing, pathogen detection and control, food preservation, textiles, fabrics, etc. The present review describes the different types of fungi used for the biosyntheses of silver nanoparticles (AgNPs), along with their characterisation and possible biological applications. AgNPs synthesised by other physical and chemical methods are expensive and have toxic substances adsorbed onto them. Therefore, green, simple and effective approaches have been chosen for the biosynthesis of AgNPs, which are very important because of their lower toxicity and environmentally friendly behaviour. AgNPs synthesised using fungi have high monodispersity, specific composition and a narrow size range. In this regard, among the different biological methods used for metal nanoparticle synthesis, fungi are considered to be a superior biogenic method owing to their diversity and better size control. To further understand the biosynthesis of AgNPs using various fungi and evaluate their potential applications, this review discusses the antimicrobial, antibacterial, antifungal, antiviral, antidermatophytic, anti-inflammatory, antitumor, hepatoprotective, cytotoxic, hypotensive, and immunomodulatory activities of these AgNPs. The synthesis of AgNPs using fungi is a clean, green, inexpensive, eco-friendly, reliable, and safe method that can be used for a range of applications in real life for the benefit of human beings

A simple biogenic route to rapid synthesis of Au@TiO2 nanocomposites by electrochemically active biofilms

<div>Deposition of gold on titanium dioxide (TiO2) nanoparticles is highly beneficial for maximizing the efficiency of many photocatalytic reactions. In this study, we have reported for the first time the use of an electrochemically active biofilm (EAB) for the synthesis of Au@TiO2 nanocomposite with sodium acetate as the electron donor. The EAB acts as an</div><div>electron generator for the reduction of gold ions on the</div><div>surface of TiO2 nanoparticles. It was observed that the</div><div>TiO2 plays not only as a support for the gold</div><div>nanoparticles but also as a storage of electrons</div><div>produced by the EAB within the particles. These</div><div>stored electrons dramatically increase the reduction of</div><div>gold ions and hence we have observed the formation</div><div>of the Au@TiO2 nanocomposites within 90 min. A mechanism of the nanocomposite formation is also</div><div>proposed. The as-synthesized nanocomposites were</div><div>characterized by UV–Vis absorption spectroscopy to</div><div>monitor the proper formation of the nanocomposites.</div><div>X-ray diffraction and transmission electron microscopic</div><div>analyses were performed to determine the structural and microstructural properties of the nanocomposites.</div><div>High-resolution transmission electron micrographs depict the proper formation of the Au@TiO2 nanocomposites with gold nanoparticle size varying from 5 to 10 nm with an increase in the gold precursor concentration. Zeta potential measurements were used to investigate surface charges of the as-synthesized nanocomposites. This novel biogenic</div><div>route represents a unique pathway for the low cost,</div><div>eco-friendly, rapid, and controlled synthesis of nanostructured Au@TiO2 hybrid systems which will truly</div><div>revolutionize the synthetic fields of nanocomposites.</div

CdS-graphene Nanocomposite for Efficient Visible-light-driven Photocatalytic and Photoelectrochemical Applications

<div>This paper reports cadmium sulphide nanoparticles-(CdS NPs)-graphene nanocomposite (CdS-Graphene),</div><div>prepared by a simple method, in which CdS NPs were anchored/ decorated successfully onto graphene sheets. The as-synthesized nanocomposite was characterized using standard characterization techniques. A combination of CdS NPs with the optimal amount of two-dimensional graphene sheets had a profound influence on the properties of the resulting hybrid nanocomposite, such as enhanced optical, photocatalytic, and photo-electronic properties. The photocatalytic degradation ability of the CdS-Graphene nanocomposite was evaluated by degrading different types of dyes in the dark and under visible light irradiation. Furthermore, the photoelectrode performance of the nanocomposite was evaluated by different electrochemical techniques. The results showed that the CdS-Graphene nanocomposite can serve as an efficient visible-light-driven photocatalyst as well as photoelectrochemical performance for optoelectronic applications. The significantly enhanced photocatalytic and photoelectrochemical performance of the CdS-Graphene nanocomposite was attributed to the synergistic effects of the enhanced light absorption behaviour and high electron conductivity of the CdS NPs and graphene sheets, which facilitates charge separation and lengthens the lifetime of photogenerated electron–hole pairs by reducing the recombination rate. The as-synthesized narrow band gap CdS-Graphene nanocomposite can be used for wide range of visible light-induced photocatalytic and photoelectrochemical based applications.</div

Environmentally sustainable biogenic fabrication of AuNP decorated-graphitic g-C3N4 nanostructures towards improved photoelectrochemical performances

<div>Noble-metal gold (Au) nanoparticles (NPs) anchored/decorated on polymeric graphitic carbon nitride (g-</div><div>C3N4), as a nanostructure, was fabricated by a simple, single step, and an environmentally friendly</div><div>synthesis approach using single-strain-developed biofilm as a reducing tool. The well deposited/</div><div>anchored AuNPs on the sheet-like structure of g-C3N4 exhibited high photoelectrochemical</div><div>performance under visible-light irradiation. The Au-g-C3N4 nanostructures behaved as a plasmonic</div><div>material. The nanostructures were analyzed using standard characterization techniques. The effect of</div><div>AuNPs deposition on the photoelectrochemical performance of the Au-g-C3N4 nanostructures was</div><div>examined by linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), incident</div><div>photon-to-current efficiency (IPCE) and cyclic voltammetry (CV) in the dark and under visible-light</div><div>irradiation. The optimal charge transfer resistance for Au-g-C3N4 nanostructures (6 mM) recorded at</div><div>18.21 1.00 U cm2 and high electron transfer efficiency, as determined by EIS. The improved</div><div>photoelectrochemical performance of the Au-g-C3N4 nanostructures was attributed to the synergistic</div><div>effects between the conduction band minimum of g-C3N4 and the plasmonic band of AuNPs, including</div><div>high optical absorption, uniform distribution, and nanoscale particle size. This simple, biogenic approach</div><div>opens up new ways of producing photoactive Au-g-C3N4 nanostructures for potential practical</div><div>applications, such as visible light-induced photonic materials for real device development.</div