An overview on Ag modified g-C3N4 based nanostructured materials for energy and environmental applications (original) (raw)
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Journal of Metals, Materials and Minerals, 2022
In this study, the g-C3N4/Ag-TiO2 composite photocatalysts were prepared to enhance the efficient utilization of solar energy. The g-C3N4 was synthesized by facile heat treatment of urea at 600℃ for 4 h, and 0.05 wt% to 3 wt% Ag-TiO2 were obtained through the chemical reduction method. The composite photocatalysts were prepared by mixing the g-C3N4 and Ag-TiO2 with a weight ratio of 50:50 at room temperature. The photocatalytic efficiency was carried out by using 0.05 g of photocatalysts with 10 mg•L-1 of rhodamine B 120 mL under 60 min of visible light irradiation. The experimental results indicated that a sample with 0.1 wt% Ag-TiO2 could degrade rhodamine B up to 21.21%. The g-C3N4/(0.1 wt% Ag-TiO2) and g-C3N4 showed rhodamine B degradation efficiency up to 100%, which was 10.4 times and 4.7 times of pure TiO2 and 0.1 wt% Ag-TiO2, respectively. It can be suggested that the Ag deposited on TiO2 played an important role in the absorption capability under the visible light through the surface plasmon resonance effect. In addition, heterojunction between g-C3N4 and TiO2 could reduce the recombination of electron-hole pairs.
Applied Catalysis A: General, 2011
Enhanced photocatalytic degradation of methylene blue (MB) using graphitic carbon nitride/titanium dioxide (g-C 3 N 4 /TiO 2 ) catalyst films has been demonstrated in this present work. The g-C 3 N 4 /TiO 2 composites were prepared by directly heating the mixture of melamine and pre-synthesized TiO 2 nanoparticles in Ar gas flow. The g-C 3 N 4 contents in the g-C 3 N 4 /TiO 2 composites were varied as 0, 20, 50 and 70 wt%. It was found that the visible-light-induced photocatalytic degradation of MB was remarkably increased upon coupling TiO 2 with g-C 3 N 4 and the best degradation performance of $70% was obtained from 50 wt% g-C 3 N 4 loading content. Results from UV-vis absorption study, Electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggest that the improved photoactivity is due to a decrease in band gap energy, an increased light absorption in visible light region and possibly an enhanced electron-hole separation efficiency as a result of effective interfacial electron transfer between TiO 2 and g-C 3 N 4 of the g-C 3 N 4 /TiO 2 composite film. Based on the obtained results, the possible MB degradation mechanism is ascribed mainly to the generation of active species induced by the photogenerated electrons.
Diamond and Related Materials, 2021
In this work, we focus on synthesizing g-C 3 N 4 nanosheets with a large surface area for enhanced solar light photocatalytic performance via a simple thermal polymerization of a low-cost urea precursor in enclosed conditions. The effects of annealing duration on the phase formation, structure, and optical and photocatalytic properties of the g-C 3 N 4 nanosheets were investigated. The characterization analysis revealed that g-C 3 N 4 nanosheets with different textures, including stacked-layer, porous and ultrathin morphologies, were obtained by controlling the annealing time. The prepared g-C 3 N 4 samples offer a large specific surface area, narrow band gap and efficient separation of photogenerated electron-hole pairs with increasing annealing duration. The photocatalytic properties of the as-synthesized g-C 3 N 4 samples were examined by measuring the degradation of rhodamine B (RhB) under simulated solar irradiation. With a 100% RhB solution (10 ppm) decomposed by exposure to solar irradiation for 60 min, ultrathin g-C 3 N 4 shows considerable potential in practical applications concerning environmental remediation, especially in large-scale applications in industry.
Applied Surface Science, 2017
In this study, mpg-C 3 N 4 /Ag composites of surface plasmon resonance structures were fabricated to improve the photocatalytic and photoelectrocatalytic activities of g-C 3 N 4 via photo-assisted reduction method, which were characterized by XRD, EDS, XPS, FT-IR, FE-SEM, TEM, DRS and BET. The photocatalytic and photoelectrocatalytic activities were evaluated by the degradation of methylene blue (MB) and the oxygen reduction experiment under visible light. The results showed the photocatalytic and photoelectrocatalytic activities were dependent on the weight ratio of Ag and the optimum photocatalytic activity of mpg-C 3 N 4 /Ag at a weight ratio of 3% is almost 3 times as high as that of mpg-C 3 N 4. Additionally, mpg-C 3 N 4 /Ag exhibited a significantly enhanced oxygen reduction performance under visible light. The limit current density was increased about 2 times by the modification of Ag nanoparticles, compared with that of pristine mpg-C 3 N 4. Finally, based on the first principle, the enhancement mechanism of the photocatalytic and photoelectrocatalytic activities was discussed by the calculation on the band structure and density of states in the mpg-C 3 N 4 /Ag composites. The appropriate amount of Ag modification would cause the surface plasmon resonance effect, which improved the photocatalytic, photoelectrocatalytic, and oxygen reduction activities of mpg-C 3 N 4 .
Nanocomposites for Visible Light-induced Photocatalysis
The carbonaceous p-conjugated/polymeric materials have been emerging as suitable materials to synthesize nanocomposites because of their attractive nanoporous structure, controllable surface chemistry, mechanical strength and favourable interactions with the semiconducting materials. The photocatalytic performances of the traditional polymeric materials are generally poor. Their performances can be greatly improved by coupling with a host semiconducting material. This is mainly due to their unique crystal structure, stability, high conductivities, nature of formation, efficient catalytic activity, promising electrochemical and optical properties. These polymeric nanocomposites act as photo sensitizers and good visible light absorbers due to p-p* electronic transitions. In this chapter the preparation methods, microstructure analysis and photocatalytic mechanism of graphitic carbon nitride (g-C 3 N 4) and various carbonaceous p-conjugated/polymeric material composite catalysts are focused. In particular, modification of g-C 3 N 4 by various carbonaceous p-conjugated/polymeric materials result in hybridization owing to strong p-p stacking interaction, which stabilizes the hybrid nanostructure and efficiently utilize the solar spectra by extending the photocatalytic applications in NO removal, CO 2 reduction and oxygen reduction reactions, water splitting to liberate H 2 fuel and degradation of pollutants. The challenges of various p-conjugated/polymeric material modified nanocomposites of g-C 3 N 4 in the field of photocatalysis are also highlighted in this chapter to extend their applications in sustainable energy development.
Materials
In this study, heterostructured g-C3N4/Ag–TiO2 nanocomposites were successfully fabricated using an easily accessible hydrothermal route. Various analytical tools were employed to investigate the surface morphology, crystal structure, specific surface area, and optical properties of as-synthesized samples. XRD and TEM characterization results provided evidence of the successful fabrication of the ternary g-C3N4/Ag–TiO2 heterostructured nanocomposite. The heterostructured g-C3N4/Ag–TiO2 nanocomposite exhibited the best degradation efficiency of 98.04% against rhodamine B (RhB) within 180 min under visible LED light irradiation. The g-C3N4/Ag–TiO2 nanocomposite exhibited an apparent reaction rate constant 13.16, 4.7, and 1.33 times higher than that of TiO2, Ag–TiO2, and g-C3N4, respectively. The g-C3N4/Ag–TiO2 ternary composite demonstrated higher photocatalytic activity than pristine TiO2 and binary Ag–TiO2 photocatalysts for the degradation of RhB under visible LED light irradiation...
Materials Letters, 2019
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2021
In later years, numerous viable photocatalysts have been created in order to illuminate the issues of natural toxins. In this work, heterostructured photocatalysts Ag3VO4/g-C3N4 were prepared by effortless hydrothermal route in order to anchor Ag3VO4 on the surface of the g-C3N4 nanosheets. The prepared samples were fairly characterized using X-ray diffraction (XRD), Energy dispersive analysis of X-rays (EDAX), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-DRS), photoluminescence, and X-ray photoelectron spectroscopy (XPS) techniques. The photocatalytic activity of the samples was evaluated by degrading malachite green (MG) and 2,4 dimethyl phenol (DMP) in aqueous solution under visible light irradiation. Compared with Ag3VO4 and g-C3N4, the heterojuncted photocatalyst 50 wt% Ag3VO4/g-C3N4 exhibits the best activity such as high degradation efficiency (99%), high apparent constant (0.0923 min− 1) and long term...
RSC Advances, 2016
Graphitic carbon nitride (g-C 3 N 4) is gaining more and more importance as a photocatalytic material due to its promising electronic band structure and high thermal and chemical stability. Very recently, a variety of nanostructured g-C 3 N 4 photocatalysts with varying shapes, sizes, morphologies and electronic band structures have been reported for application in photocatalytic research. This critical review represents an extensive overview of the synthesis of a variety of g-C 3 N 4 nanostructured materials with a controllable structure, morphology and surface modification for superior electronic properties. This article highlights the design of efficient photocatalysts for the splitting of water into hydrogen gas using solar energy. Finally, in the summary and outlook, this article highlights the ongoing challenges and opportunities of g-C 3 N 4. It is also hoped that this review will stimulate further investigation and will open up new possibilities to develop new hybrid g-C 3 N 4 materials with new and exciting applications. Sulagna Patnaik completed her master's degree at the Regional Engineering College, Rourkela, in 1989 in chemistry. Then, she became a lecturer in chemistry at Rayagada Autonomous College, Odisha, in 1991. She is presently working at Nimapara Autonomous College and pursuing research work at the Centre for Nanoscience and Nanotechnology, SOA University, Bhubaneswar. She has published one research article in an international journal. Her research work is focused on the development of modied C 3 N 4based photocatalysts for hydrogen energy production and pollution abatement. Dr Satyabadi Martha completed his Master of Science (M.Sc.