Chongqing Technology and Business University

About: Chongqing Technology and Business University is a education organization based out in Chongqing, China. It is known for research contribution in the topics: Photocatalysis & Catalysis. The organization has 3090 authors who have published 3321 publications receiving 52022 citations.

Graphitic carbon nitride based nanocomposites: a review

Abstract: Graphitic carbon nitride (g-C3N4), as an intriguing earth-abundant visible light photocatalyst, possesses a unique two-dimensional structure, excellent chemical stability and tunable electronic structure. Pure g-C3N4 suffers from rapid recombination of photo-generated electron–hole pairs resulting in low photocatalytic activity. Because of the unique electronic structure, the g-C3N4 could act as an eminent candidate for coupling with various functional materials to enhance the performance. According to the discrepancies in the photocatalytic mechanism and process, six primary systems of g-C3N4-based nanocomposites can be classified and summarized: namely, the g-C3N4 based metal-free heterojunction, the g-C3N4/single metal oxide (metal sulfide) heterojunction, g-C3N4/composite oxide, the g-C3N4/halide heterojunction, g-C3N4/noble metal heterostructures, and the g-C3N4 based complex system. Apart from the depiction of the fabrication methods, heterojunction structure and multifunctional application of the g-C3N4-based nanocomposites, we emphasize and elaborate on the underlying mechanisms in the photocatalytic activity enhancement of g-C3N4-based nanocomposites. The unique functions of the p–n junction (semiconductor/semiconductor heterostructures), the Schottky junction (metal/semiconductor heterostructures), the surface plasmon resonance (SPR) effect, photosensitization, superconductivity, etc. are utilized in the photocatalytic processes. Furthermore, the enhanced performance of g-C3N4-based nanocomposites has been widely employed in environmental and energetic applications such as photocatalytic degradation of pollutants, photocatalytic hydrogen generation, carbon dioxide reduction, disinfection, and supercapacitors. This critical review ends with a summary and some perspectives on the challenges and new directions in exploring g-C3N4-based advanced nanomaterials.

In situ construction of g-C3N4/g-C3N4 metal-free heterojunction for enhanced visible-light photocatalysis.

Abstract: The photocatalytic performance of the star photocatalyst g-C3N4 was restricted by the low efficiency because of the fast charge recombination. The present work developed a facile in situ method to construct g-C3N4/g-C3N4 metal-free isotype heterojunction with molecular composite precursors with the aim to greatly promote the charge separation. Considering the fact that g-C3N4 samples prepared from urea and thiourea separately have different band structure, the molecular composite precursors of urea and thiourea were treated simultaneously under the same thermal conditions, in situ creating a novel layered g-C3N4/g-C3N4 metal-free heterojunction (g-g CN heterojunction). This synthesis method is facile, economic, and environmentally benign using easily available earth-abundant green precursors. The confirmation of isotype g-g CN heterojunction was based on XRD, HRTEM, valence band XPS, ns-level PL, photocurrent, and EIS measurement. Upon visible-light irradiation, the photogenerated electrons transfer from ...

Efficient synthesis of polymeric g-C3N4 layered materials as novel efficient visible light driven photocatalysts

Abstract: In order to develop efficient visible light driven photocatalysts for environmental applications, novel polymeric g-C3N4 layered materials with high surface areas are synthesized efficiently from an oxygen-containing precursor by directly treating urea in air between 450 and 600 °C, without the assistance of a template for the first time. The as-prepared g-C3N4 materials with strong visible light absorption have a band gap around 2.7 eV. The crystallinity and specific surface areas of g-C3N4 increases simultaneously when the heating temperatures increases. The g-C3N4 materials are demonstrated to exhibit much higher visible light photocatalytic activity than that of C-doped TiO2 and g-C3N4 prepared from dicyanamide for the degradation of aqueous RhB. The large surface areas, layered structure and band structure in all contributed to the efficient visible light photocatalytic activity. The efficient synthesis method for g-C3N4 combined with efficient photocatalytic activity is of significant interest for environmental pollutants degradation and solar energy conversion in large scale applications.

Bridging the g-C3N4 Interlayers for Enhanced Photocatalysis

Abstract: Graphitic carbon nitride (g-C3N4) has been widely investigated and applied in photocatalysis and catalysis, but its performance is still unsatisfactory. Here, we demonstrated that K-doped g-C3N4 with a unique electronic structure possessed highly enhanced visible-light photocatalytic performance for NO removal, which was superior to Na-doped g-C3N4. DFT calculations revealed that K or Na doping can narrow the bandgap of g-C3N4. K atoms, intercalated into the g-C3N4 interlayer via bridging the layers, could decrease the electronic localization and extend the π conjugated system, whereas Na atoms tended to be doped into the CN planes and increased the in-planar electron density. On the basis of theoretical calculation results, we synthesized K-doped g-C3N4 and Na-doped g-C3N4 by a facile thermal polymerization method. Consistent with the theoretical prediction, it was found that K was intercalated into the space between the g-C3N4 layers. The K-intercalated g-C3N4 sample showed increased visible-light absor...

MnO2-based nanostructures for high-performance supercapacitors

Abstract: MnO2-based materials have been intensively investigated for use in pseudocapacitors due to their high theoretical specific capacitance, good chemical and thermal stability, natural abundance, environmental benignity and low cost. In this review, several main factors that affect the electrochemical properties of MnO2-based electrodes are presented. Various strategic design and synthetic methods of MnO2-based electrode materials for enhanced electrochemical performance are highlighted and summarized. Finally, the challenges and future directions toward the development of MnO2-based nanostructured electrode materials for high performance supercapacitors (SCs) are discussed.