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Carbon coated-Cu nanoparticles as a cocatalyst of g-C3N4 for enhanced photocatalytic H2 evolution activity under visible-light irradiation
摘要： The photocatalytic H2 evolution is an important technology to solve the energy crisis. The hydrogen evolution rate of the g-C3N4 system in triethanolamine solution as sacrificial agent is obvious higher than in methanol solution. But up to now, most of the Cu nanoparticles as cocatalyst of g-C3N4 photocatalytic systems for hydrogen evolution are performed in methanol solution because Cu nanoparticles are unstable in triethanolamine solution. Here, carbon coated-Cu nanoparticles as cocatalyst of g-C3N4 composites (Cu@C/g-C3N4) were prepared by simple two-steps technology of annealing then grinding. The compositions, morphology and optical and photoelectrochemical (PEC) properties of the composites were characterized by means of physicochemical techniques. The prepared composition was used to generate hydrogen under visible light irradiation in triethanolamine solution. The results displayed that the hydrogen evolution rate of the optimal Cu@C/g-C3N4 was up to 265.1 μmol g-1 h-1 that is close to the activity of 0.5% Pt/g-C3N4, and after four repeated reactions, the photocatalytic activity decreased only by about 15%. The good photocatalytic activity and stability result from Cu nanoparticles increase the transfer efficiency of charge carriers by trapping the photogenerated electrons produced by g-C3N4 and the protective effect of carbon layer on Cu nanoparticles.
关键词： Cu nanoparticles,Visible-light,Graphite carbon nitride,Photocatalytic H2 evolution,Carbon coating layer
更新于2025-09-23 15:21:01
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Highly Efficient Solara??Catalytic Degradation of Reactive Black 5 Dye Using Mesoporous Plasmonic Ag/ga??C <sub/>3</sub> N <sub/>4</sub> Nanocomposites
摘要： An azo dye, Reactive Black 5 (RB5), was degraded by three photocatalysts of g-C3N4, Ag(2 %)/g-C3N4, and Ag(5 %)/g-C3N4 with the specific surface areas of 34.41, 28.70, and 35.58 m2 g?1 and the band gaps of 2.52, 1.56, and 1.71 eV under sunlight illumination, respectively. The results showed 40 mg/L of g-C3N4 could degrade completely 10 ppm RB5 at pH 3.4 within 10 min under sunlight irradiation with the first-order rate constant of 0.312 min?1. Under the same conditions, the complete degradation time of RB5 reduced to 5 and 7 min when the plasmonic nanocomposites of Ag (2 %)/g-C3N4 and Ag (5 %)/g-C3N4 were used as photocatalysts, respectively. Ag content had an important influence on the photocatalytic activity of g-C3N4 against RB5 so that Ag (2 %)/g-C3N4 possessed the best photocatalytic efficiency with the rate constant of 0.795 min?1. In fact, Ag nanoparticles through the surface plasmon resonance effects and by accepting the photogenerated electrons could improve the visible-light absorption and increase charge separation of g-C3N4. The results showed superoxide radical is the main oxidant in the photodegradation of RB5.
关键词： Surface Plasmon Resonance,Photocatalysis,RB5 dye,Graphitic carbon nitride,Ag/g-C3N4 nanocomposites
更新于2025-09-23 15:19:57
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Highly solid-luminescent graphitic C <sub/>3</sub> N <sub/>4</sub> nanotubes for white light-emitting diodes
摘要： Graphitic C3N4 (g-C3N4) has seldom been used for white light-emitting diode (LED) phosphors due to its low solid-state fluorescence quantum yield. Here, we report a facile thermal condensation path for the synthesis of g-C3N4 nanotubes stuffed with quantum dots. The g-C3N4 nanotubes have a high fluorescence quantum yield of 30.92% in the solid state. Nitrogen-rich and graphitic carbon-free features are responsible for the enhanced quantum efficiency. The photoluminescence quantum yield can be controlled and improved by the reaction temperature. We finally demonstrate white light emission by coating the highly solid-luminescent g-C3N4 nanotubes as phosphors onto a 370 nm ultraviolet LED.
关键词： graphitic carbon nitride,nanotubes,fluorescence,phosphors,white LEDs
更新于2025-09-23 15:19:57
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Efficient photocatalytic synthesis of l-glutamate using a self-assembled carbon nitride/sulfur/porphyrin catalyst
摘要： Mimicking natural photosynthesis is a promising way to produce fine chemicals, yet there is a need for efficient catalysts. Here, we synthesized a photocatalyst made of self-assembled graphitic carbon nitride/sulfur/cobalt (III) tetraphenyl porphyrin, and we used this photocatalyst for production of the l-glutamate amino acid in 93.6% yield. Regeneration of the 1,4-dihydronicotinamide adenine dinucleotide cofactor under visible light reached 88.3%.
关键词： Graphitic carbon nitride/sulfur/cobalt (III) tetraphenyl porphyrin photocatalyst,Mimicking natural photosynthesis,Amino acid (l-glutamate) production,1,4-Dihydronicotinamide adenine dinucleotide cofactor regeneration
更新于2025-09-23 15:19:57
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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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A sensitive method to monitor catechol by using graphitic carbon nitride quantum dots as coreactants in Ru(bpy)32+-based electrochemiluminescent system
摘要： Graphitic carbon nitride quantum dots (g-CNQDs) with special structures have exhibited fascinating advantages over the common QDs. In this work, we report a novel Ru(bpy)3 2+/g-CNQDs electrochemiluminescence (ECL) system, and the effect of g-CNQDs on the ECL signal of Ru(bpy)3 2+ was discussed. It was found that g-CNQDs containing in proposed ECL system played an important coreactant role in ECL signal enhancement of Ru(bpy)3 2+, which was proved by electrochemical, ultraviolet, and ECL experiments. Based on the quenching effect of catechol on the ECL signal of Ru(bpy)3 2+/g-CNQDs, a quenching-based ECL system was designed for catechol determination. The ECL sensing system demonstrated high sensitivity to catechol, with a linear range from 10 nM to 2 mM and a detection limit of 2.5 nM (S/N = 3). The sensor was adopted for catechol analysis in tea samples with satisfactory results.
关键词： Detection,Ru(bpy)3 2+,Electrochemiluminescence,Graphitic carbon nitride quantum dots,Catechol
更新于2025-09-23 15:19:57
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Realizing Synergistic Effect of Electronic Modulation and Nanostructure Engineering over Graphitic Carbon Nitride for Highly Efficient Visible-Light H2 Production Coupled with Benzyl Alcohol Oxidation
摘要： Photocatalytic H2 production based on g-C3N4 faces enormous challenging issues including limited visible-light absorption, poor separation and transfer abilities of photo-generated electron-hole pairs. Herein, we realize the synergistic effect of nanostructure engineering and electronic modulation with a supramolecular assembly mediated synthesis of heteroatom doped g-C3N4 hierarchical mesoporous spheres. The favorable doping site and possible effect on electronic structure are disclosed by DFT calculation with supporting experimental analysis. Impressively, S-doped g-C3N4 delivers a 13.2 times higher H2 production rate than bulk g-C3N4 under visible-light. More importantly, as the dual functional photocatalyst for H2 production and selective oxidation of benzyl alcohol, it can exhibit outstanding activity with a H2/benzaldehyde production rate of 3.76/3.87 μmol h-1, respectively. This work not only provide a new rationale for photocatalytic performance enhancement, but also shed new light on the highly efficient utilization of solar energy by coupling H2 generation with value added chemical production.
关键词： graphitic carbon nitride,hierarchical mesoporous spheres,DFT calculation,benzyl alcohol oxidation,photocatalytic hydrogen production
更新于2025-09-23 15:19:57
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Conductivity tuning of charged triazine and heptazine graphitic carbon nitride (g-C3N4) quantum dots via nonmetal (B, O, S, P) doping: DFT calculations
摘要： Chemical doping of graphitic carbon nitride (g-C3N4) quantum dots with nontoxic heteroatoms has proven to be an effective means for tuning the electrical properties of this two-dimensional (2D) nanomaterial. In this investigation, triazine (tg-CN) and heptazine (hg-CN) clusters were doped with the p-block (B, O, S, and P) elements, and were further compared in terms of siting and conductance using density functional theory (DFT) at the HSE06/6-311tG* level. The calculation results predicted that B doping in both types of g-C3N4 was favored in place of carbon atoms while the O, S, and P dopants preferred nitrogen atoms, where P siting was dependent on the type of material. Both the initial HOMO–LUMO gap and global hardness were decreased after the substitution, with the most substantial changes after the O and S doping in the hg-CN and tg-CN structures, respectively. The HOMO–LUMO gap changed most significantly (by up to 3.79 eV) with the [t/(cid:0) ] charge switching for the O-doped nanocluster. In contrast to hg-CN, tg-CN turned from an insulator into metallic or half-metallic material upon electron charging. Finally, both hg-CN and tg-CN became better electrophiles after modification, particularly with B doping.
关键词： Doping,Semiconductor,Graphitic carbon nitride,DFT,Quantum dot
更新于2025-09-23 15:19:57
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Selectively Photocatalytic Oxidation of Low Concentration Methane over Graphitic Carbon Nitride Decorated Tungsten Bronze Cesium
摘要： Although the traditional thermal catalysis is usually used to convert the methane into value-added products, its high reaction temperature results in low performance-price ratio in conversion of low concentration methane. In this regard, we synthesized a series of mace-like g-C3N4 decorated Cs0.33WO3 nanocomposites for photocatalytic conversion of low concentration methane under mild conditions. The optimized g-C3N4@Cs0.33WO3 (weight ratio = 3:7) photocatalyst selectively converted low concentration methane (1000 ppm) into methanol with yield of 4.38 μmol/h/g under light irradiation and at room temperature. Both performance experiments and trapping experiments verified that the methane activation and methyl oxidation involved in photocatalytic conversion process of methane. The ?O2- firstly activated the methane to methyl on the surface of the g-C3N4 in the composite and then the photogenerated electrons from the Cs0.33WO3 in the composite inhibited the peroxidation and increased the generation of methanol. This research provides a new route to design and synthesize photocatalysts for converting methane into value-added chemicals.
关键词： Selective Conversion,Low concentration methane,Tungsten Bronze Cesium,Photocatalytic Methane Conversion,Graphic Carbon Nitride
更新于2025-09-19 17:15:36
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One-pot, solid-state loading of Zn into g-C3N4 for increasing the population of photoexcited electrons and the rate of photocatalytic hydrogen evolution
摘要： In this research, we load g-C3N4 with Zn through a simple, one-pot solid-state route that results in appreciably improved photocatalytic activity for H2 evolution under visible light. X-ray photoelectron spectroscopy and synchrotron X-ray absorption near edge structure spectroscopy confirm that the Zn species are present in the +2 oxidation state, coordinated to O atoms in the form of nanoclusters. Following the Zn loading, the host g-C3N4 absorbs more light in the UV and visible regions, while its physical features are almost unaltered. In the absence of any co-catalysts, a H2 evolution rate as high as 26.3 μmol/g·h can be achieved by g-C3N4 loaded with 0.2 atomic% of Zn, more than 8 times higher than that of g-C3N4 (3 μmol/g·h). Our results then provide strong evidences that the photocatalytic activity of Zn-loaded g-C3N4 for H2 evolution is directly controlled by the population of photoexcited electrons.
关键词： Zinc loading,Carbon nitride,Hydrogen evolution,Photocatalysis
更新于2025-09-19 17:15:36