UV-visible-NIR active smart photocatalytic system based on NaYbF4:Tm3+ upconverting particles and Ag3PO4/H2O2 for photocatalytic processes under both light on/light off conditions

The development of broad-spectrum photocatalytic materials that allow the use of a larger portion (UV to NIR) of the solar spectrum for photocatalytic processes has attracted greater attention. Among the...

Plasmonic Bi NPs-accelerated interfacial charge transfer for enhanced solar-driven ciprofloxacin mineralization

High-efficient mineralization of refractory organic pollutants is an admittedly difficult problem for most photocatalytic processes. Herein, a hierarchical type-II heterojunction of Bi2MoO6/Bi/BiOBr-x (BMO/Bi/BOB-x) was successfully fabricated via one-pot solvothermal method....

Sulfide-Based Photocatalysts Using Visible Light, with Special Focus on In2S3, SnS2 and ZnIn2S4

Sulfides are frequently used as photocatalysts, since they absorb visible light better than many oxides. They have the disadvantage of being more easily photocorroded. This occurs mostly in oxidizing conditions; therefore, they are commonly used instead in reduction processes, such as CO2 reduction to fuels or H2 production. Here a summary will be presented of a number of sulfides used in several photocatalytic processes; where appropriate, some recent reviews will be presented of their behaviour. Results obtained in recent years by our group using some octahedral sulfides will be shown, showing how to determine their wavelength-dependent photocatalytic activities, checking their mechanisms in some cases, and verifying how they can be modified to extend their wavelength range of activity. It will be shown here as well how using photocatalytic or photoelectrochemical setups, by combining some enzymes with these sulfides, allows achieving the photo-splitting of water into H2 and O2, thus constituting a scheme of artificial photosynthesis.

Preparation and Application of Nb2O5 Nanofibers in CO2 Photoconversion

Increasing global warming due to NOx, CO2, and CH4, is significantly harming ecosystems and life worldwide. One promising methodology is converting pollutants into valuable chemicals via photocatalytic processes (by reusable photocatalysts). In this context, the present work aimed to produce a Nb2O5 photocatalyst nanofiber system by electrospinning to convert CO2. Based on the collected data, the calcination at 600 ∘C for 2 h resulted in the best condition to obtain nanofibers with homogeneous surfaces and an average diameter of 84 nm. As a result, the Nb2O5 nanofibers converted CO2 mostly into CO and CH4, reaching values around 8.5 μmol g−1 and 0.55 μmol g−1, respectively.

Photocatalytic Processes for Environmental Applications

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

Effect of UVc and UVA Photocatalytic Processes on Tetracycline Removal Using Cus-Coated Magnetic Activated Carbon Nanocomposite: A Comparative Study

In this study, we synthesized a novel MAC nanocomposite using almond’s green hull coated with CuS. The whole set of experiments have been conducted inside a batch (discontinuous reactor system) at room temperature. The effectiveness of different parameters in tetracycline removal pH (3, 5, 7, and 9), pollutant concentration (5–100 mg/L), nanocomposite dosage (0.025–1g/L), and contact time (5–60min) using newly synthesized nanocomposite were investigated. Based on the results, in the optimal conditions of pH = 9, nanocomposite dosage of 1g/L, pollutant concentration of 20 mg/L, contact time of 60 min, and room temperature, 95% removal efficiency was obtained. In MAC/CuS/UVc process, the removal of COD and TOC were 76.89% and 566.84% respectively meanwhile, these values in MAC/CuS/UVA process were 74.19% and 62.11%, respectively. The results of nanocomposite stability and magnetic recovery illustrated that the removal efficiency was reduced by 1.5% in the presence of UVc and 5% in the presence of UVA lights during all six cycles. Therefore, this nanocomposite was highly capable of recycling and reuse. It can be concluded that considering the high potential of the synthesized nanocomposite, the photocatalytic efficiency of the MAC/CuS/UVc process in tetracycline synthesis was higher than MAC/CuS/UVA process.

Evaluation of Nb2O5 Ceramic Nanofibers Efficacy to Promote CO2 Photoconversion

The increase in global warming due to NOx, CO2, and CH4 harmfully different ecosystems and significantly prejudice world life. A promising methodology in this sense is the pollutant conversion into valuable chemicals from photocatalytic processes by reusable photocatalyst. In this way, the present work aimed to produce a Nb2O5 photocatalyst nanofibers system to convert CO2 by the electrospinning method. Based on the collected data, the nanofibers calcination at 600°C for 2 h resulted in the best condition to obtain a homogeneous surface with an average diameter of 84 nm. As a result, the Nb2O5 nanofibers converted CO2 mostly into CO and CH4, reaching values around 8.5 μmol g−1 and 0.55 μmol g−1, respectively.

Simulation and Computer Study of Structures and Physical Properties of Hydroxyapatite with Various Defects

Simulation and computer studies of the structural and physical properties of hydroxyapatite (HAP) with different defects are presented in this review. HAP is a well-known material that is actively used in various fields of medicine, nanotechnology, and photocatalytic processes. However, all HAP samples have various defects and are still insufficiently studied. First of all, oxygen and OH group vacancies are important defects in HAP, which significantly affect its properties. The properties of HAP are also influenced by various substitutions of atoms in the HAP crystal lattice. The results of calculations by modern density functional theory methods of HAP structures with these different defects, primarily with oxygen and hydroxyl vacancies are analyzed in this review. The results obtained show that during the structural optimization of HAP with various defects, both the parameters of the crystallographic cells of the HAP change and the entire band structure of the HAP changes (changes in the band gap). This affects the electronic, optical, and elastic properties of HAP. The review considers the results of modeling and calculation of HAP containing various defects, the applied calculation methods, and the features of the effect of these defects on the properties of HAP, which is important for many practical applications.