g-C3N4/carbon dot-based nanocomposites serve as efficacious photocatalysts for environmental purification and energy generation: A review

The use of solar energy to catalyze the photo-driven processes has attracted tremendous attention from the scientific community because of its great potential to address energy and environmental is...

Perovskite Oxide Based Materials for Energy and Environment-Oriented Photocatalysis

A review on graphitic carbon nitride (g-C3N4) based nanocomposites: Synthesis, categories, and their application in photocatalysis

The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.

https://www.mdpi.com/2073-4441/14/2/242/pdf?version=1642404093

Review on Methylene Blue: Its Properties, Uses, Toxicity and Photodegradation

On a evalue les effets de solvant sur un certain nombre de processus et on discute des resultats de l'application de l'analyse de regression lineaire multiple. Les processus etudies comportent des exemples de solubilite des gaz ou des vapeurs, des coefficients de distribution des solutes entre l'eau et une serie de solvants ainsi que des effets de solvant sur l'equilibre conformationel, sur la tautomerie ceto-enolique et sur les vitesses de reaction. On demontre que deux equations particulieres, celle de Koppel et Palm qui a ete etendue par Makitra et Pirig ainsi que celle d'Abraham, Kamlet et Taft, peuvent rendre compte d'une facon satisfaisante des effets de solvant sur ces divers processus. On note que l'interpretation des parametres obtenus a l'aide de ces equations qui impliquent des quantites macroscopiques comme le ΔG ou le ΔG 0 ne sont pas simples; des modeles sont necessaires pour interpreter ces quantites macroscopiques en fonction de quantites microscopiques qui peuvent caracteriser, par exemple, les interactions solute-solvant

Solvent effects in organic chemistry: recent developments

A review and recent advances in solar-to-hydrogen energy conversion based on photocatalytic water splitting over doped-TiO2 nanoparticles

In recent years, graphitic carbon nitride (g-C3N4) has shown promising performance as a metal-free conjugated polymer containing graphitic stacking of C3N4 layers, which are constructed from tri-s-triazine units connected by planar amino groups. Pure g-C3N4 with a band gap energy of 2.7 eV (460 nm) makes it an applicable and efficient visible-active photocatalyst for energy conversion and environmental applications. This is because of its appropriate electronic band structures, efficient optical absorption, and extraordinary thermal and chemical stability. Currently, the major focus in photocatalysis research is on the design and development of visible-light-driven photocatalysts that are stable and highly efficient for practical applications. In this current mini-review, a comprehensive survey is conducted on graphitic carbon nitride (g-C3N4) as a metal-free novel visible-light photocatalyst and the progress in the synthesis and design of high-efficiency g-C3N4-based nanomaterial photocatalysts with controllable structures and morphologies is discussed in detail. Various approaches for modifying the electronic band structure and visible-light harvesting, including metal (cation), non-metal (anion) doping, noble metal loading, and composite formation with other semiconductors are discussed in detail. Photocatalytic applications of g-C3N4 as metal-free catalysts in photocatalytic water splitting for hydrogen production, CO2 photoreduction, organic pollutant degradation, and bacterial disinfections are introduced and discussed in detail. Finally, this critical mini-review summarizes some outlooks on the ongoing challenges in the development of efficient and low cost metal-free g-C3N4 systems, which provide a good complement to the literature on g-C3N4 based metal-free nanomaterial photocatalysts.

A mini-review on the synthesis and structural modification of g-C3N4-based materials, and their applications in solar energy conversion and environmental remediation

In the present work, bare TiO2 and different molar concentrations of iron (Fe3+)-doped TiO2 photocatalysts (0.05−1 mol % Fe) were prepared by a simple precipitation method for photocatalytic hydrogen production and degradation of organic pollutants (MO and 4-CP) under light irradiation of λ ≥ 320 nm. XRD revealed the presence of anatase phase for both bare TiO2 and Fe doped titania. Based on the XPS results, Fe3+ ions are hardly seen may be attributed to the location of iron inside the titania matrix rather than their appearance at the surface. UV–vis-DRS of the doped titania demonstrated a redshift toward visible region owing to the reduced bandgap energy. N2 adsorption results showed that the doped materials have higher surface area compared to bare TiO2 due to decrease particle size. Importantly, electrochemical experiments (electrochemical impedance spectroscopy (EIS), photocurrent (PC), and photoluminescence (PL)) revealed that higher photogenerated charge carrier separation efficiency of iron-doped titania. Results showed that the 0.1 mol % Fe doped TiO2 exhibited the highest photocatalytic activity for both degradation and H2 evolution reactions. Furthermore, high surface area, small particle size and enhanced visible-light absorption as well as improved charge transfer and separation are believed to be responsible for the improvement of photocatalytic activity of the doped materials.

Enhanced photocatalytic hydrogen production and degradation of organic pollutants from Fe (III) doped TiO2 nanoparticles

Herein, porous graphitic carbon nitrides (g-C3N4) were synthesized via a one-step pyrolysis process using different low-cost, environmentally benign, nitrogen-rich organic precursors, namely, urea, thiourea, and melamine. The physicochemical and photophysical properties of the obtained g-C3N4 samples were characterized by X-ray diffraction (XRD), solid-state MAS NMR, X-ray photoelectron microscopy (XPS), transmission electron microscopy (TEM), N2 adsorption/desorption, thermogravimetric analysis (TGA), UV-Vis diffuse reflectance absorption spectra (DRS), photoluminescence and electrochemical measurements. This study shows that the photocatalytic hydrogen evolution under visible light is around five times higher if urea is used as the g-C3N4 precursor instead of thiourea or melamine. This finding is confirmed by the lower degree of polymerization of the g-C3N4 sample formed from urea, leading to an altered porous structure, higher pore volume, and enhanced surface area. Moreover, the resulting structural imperfections lead to slightly more active sites as indicated by the most negative conduction band potential in urea-based g-C3N4.

Mohammed Ismael

Papers

A review on graphitic carbon nitride (g-C3N4) based nanocomposites: Synthesis, categories, and their application in photocatalysis

A review and recent advances in solar-to-hydrogen energy conversion based on photocatalytic water splitting over doped-TiO2 nanoparticles

A mini-review on the synthesis and structural modification of g-C3N4-based materials, and their applications in solar energy conversion and environmental remediation

Enhanced photocatalytic hydrogen production and degradation of organic pollutants from Fe (III) doped TiO2 nanoparticles

Graphitic carbon nitride synthesized by simple pyrolysis: role of precursor in photocatalytic hydrogen production