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Effective Fixation of Carbon in ga??C <sub/>3</sub> N <sub/>4</sub> Enabled by Mga??Induced Selective Reconstruction
摘要： The methodology of metal-involved preparation for carbon materials is favored by researchers and has attracted tremendous attention. Decoupling this process and the underlying mechanism in detail are highly required. Herein, the intrinsic mechanism of carbon fixation in graphitic carbon nitride (g-C3N4) via the magnesium-involved carbonization process is reported and clarified. Magnesium can induce the displacement reaction with the small carbon nitride molecule generated by the pyrolysis of g-C3N4, thus efficiently fixing the carbon onto the in situ template of Mg3N2 product to avoid the direct volatilization. As a result, the N-doped carbon nanosheet frameworks with interconnected porous structure and suitable N content are constructed by reconstruction of carbon and nitrogen species, which exhibit a comparable photoelectric conversion efficiency (8.59%) and electrocatalytic performances to that of Pt (8.40%) for dye-sensitized solar cells.
关键词： magnesium inducement,reconstruction mechanism,dye-sensitized solar cells,graphitic carbon nitride (g-C3N4),tri-iodide reduction
更新于2025-09-23 15:19:57
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Decoration of carbon dots over hydrogen peroxide treated graphitic carbon nitride: Exceptional photocatalytic performance in removal of different contaminants under visible light
摘要： The development of novel photocatalysts with considerable activity for completely removal of different pollutants from the environment is a dominating goal of modern chemistry. In this study, carbon dots (CDs) were adhered to the graphitic carbon nitride activated by hydrogen peroxide (ag-C3N4) to fabricate photocatalysts with exceptional ability upon visible-light illumination. Interestingly, the BET surface area, visible-light absorption characteristics, and electron-hole separation yield of the pristine g-C3N4 were improved after activation with H2O2 and decoration of CDs. The binary nanocomposite was used for degradation of MB, RhB, fuchsine, and phenol and photoreduction of Cr(VI) under visible light. The nanocomposite exhibited excellent photocatalytic performance with 100% removal of RhB in 60 min, which is almost 34.7 folds as premier as the pristine g-C3N4. Reactive species scavenging measurements displayed that ?O2?, ?OH, and h+ had significant roles for photodegradation of RhB. The possible mechanism was proposed regarding how activation with H2O2 and decoration of CDs improved the photocatalytic performance of g-C3N4. Also, stability of the composite was characterized through cyclic photocatalytic tests.
关键词： Graphitic carbon nitride,g-C3N4/CDs,Hydrogen peroxide treated g-C3N4,Visible-light-active photocatalyst
更新于2025-09-19 17:15:36
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A Review on Quantum Dots Modified g-C3N4-Based Photocatalysts with Improved Photocatalytic Activity
摘要： In the 21st century, the development of sustainable energy and advanced technologies to cope with energy shortages and environmental pollution has become vital. Semiconductor photocatalysis is a promising technology that can directly convert solar energy to chemical energy and is extensively used for its environmentally-friendly properties. In the field of photocatalysis, graphitic carbon nitride (g-C3N4) has obtained increasing interest due to its unique physicochemical properties. Therefore, numerous researchers have attempted to integrate quantum dots (QDs) with g-C3N4 to optimize the photocatalytic activity. In this review, recent progress in combining g-C3N4 with QDs for synthesizing new photocatalysts was introduced. The methods of QDs/g-C3N4-based photocatalysts synthesis are summarized. Recent studies assessing the application of photocatalytic performance and mechanism of modification of g-C3N4 with carbon quantum dots (CQDs), graphene quantum dots (GQDs), and g-C3N4 QDs are herein discussed. Lastly, challenges and future perspectives of QDs modified g-C3N4-based photocatalysts in photocatalytic applications are discussed. We hope that this review will provide a valuable overview and insight for the promotion of applications of QDs modified g-C3N4 based-photocatalysts.
关键词： organic pollutant photodegradation,H2 production,graphitic carbon nitride (g-C3N4),photocatalysis,CO2 reduction,quantum dots (QDs)
更新于2025-09-19 17:13:59
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Enhanced CH4 selectivity in CO2 photocatalytic reduction over carbon quantum dots decorated and oxygen doping g-C3N4
摘要： Graphitic carbon nitride (g-C3N4, CN) exhibits inefficient charge separation, deficient CO2 adsorption and activation sites, and sluggish surface reaction kinetics, which have been recognized as the main barriers to its application in CO2 photocatalytic reduction. In this work, carbon quantum dot (CQD) decoration and oxygen atom doping were applied to CN by a facile one-step hydrothermal method. The incorporated CQDs not only facilitate charge transfer and separation, but also provide alternative CO2 adsorption and activation sites. Further, the oxygen-atom-doped CN (OCN), in which oxygen doping is accompanied by the formation of nitrogen defects, proves to be a sustainable H+ provider by facilitating the water dissociation and oxidation half-reactions. Because of the synergistic effect of the hybridized binary CQDs/OCN addressing the three challenging issues of the CN based materials, the performance of CO2 photocatalytic conversion to CH4 over CQDs/OCN-x (x represents the volume ratio of laboratory-used H2O2 (30 wt.%) in the mixed solution) is dramatically improved by 11 times at least. The hybrid photocatalyst design and mechanism proposed in this work could inspire more rational design and fabrication of effective photocatalysts for CO2 photocatalytic conversion with a high CH4 selectivity.
关键词： carbon quantum dot,photocatalytic,graphitic carbon nitride (g-C3N4),oxygen doping,CO2 reduction
更新于2025-09-12 10:27:22