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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
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Interfacial Engineering in Functional Materials for Dye‐Sensitized Solar Cells || Graphitic Carbon Nitride Based Nanocomposites as Photoanodes
摘要： Owing to their unique properties, nanocomposites, nanostructures, and nanomaterials are playing a key role in energy conversion and in energy storage applications. In recent years, carbon-based nanostructures are used to meet the future energy demands. Nanostructured carbon nitrides (C3N4) are very attractive candidates for energy-based devices due to its high hardness, low friction coefficient, and steadfast chemical inertness. It has a great potential in solving the issues related to energy and environmental applications. Graphitic carbon nitride (g-C3N4) is one among the carbon-based nanostructures which has attracted enormous attention in green technologies for arresting solar energy, energy storage, supercapacitor, fuel cells, electrocatalysis, and environmental remediation as well as for electronic and composite industry. g-C3N4 is a well-known polymeric materials mainly consisting of carbon, nitrogen, and is also one of the oldest material discovered in 1843. It is considered as an artificial polymer in the scientific literature [1]. Its structure is shown in Figure 12.1.
关键词： Nanocomposites,Energy Storage,Energy Conversion,Photoanodes,Graphitic Carbon Nitride
更新于2025-09-12 10:27:22
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Improving Photovoltaic Performance by Using Perovskite/Surface Modified Graphitic Carbon Nitride Heterojunction
摘要： Passivation strategies were considered as one of the most efficient methods to suppress non-radiative recombination of organic-inorganic lead halide perovskite solar cells (PSCs), then, as well as, were widely employed as passivation agents, according to the previous reports. Anchoring g-leading to tremendous photovoltaic performance. An innovative 2D polymer, graphitic carbon nitride (g-C3N4), as well as various organic groups (amino, sulfonic, nitrato and hydroxy group) leading to tremendous photovoltaic performance. C3N4 and the aforementioned organic groups as additives in perovskite could both heal charged defects around the grain boundaries by passivating the charge recombination center. Besides, the crystalline quality could also be enhanced by the incorporation of g-C3N4, leading to improved conductivity of perovskite light absorber films that is beneficial for benign charge extraction efficiency. Inspiring of the underlining mechanisms, we designed a series of novel passivation molecules, functionalized g-C3N4 (F-C3N4) with assorted organic groups, yielding to champion power conversion efficiency (PCE) of 20.08% for NO3-C3N4 based p-i-n structure PSC, in comparison with that of PSC without passivation (17.85%). These findings presented an efficient strategy to understand and design multiple facets of applications of novel passivation molecules to further improve the PCE of PSCs.
关键词： passivation,graphitic carbon nitride,perovskite solar cells,organic groups,photovoltaic performance
更新于2025-09-11 14:15:04
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Nanocomposites based on 3D honeycomb-like carbon nitride with Cd0·5Zn0·5S quantum dots for efficient photocatalytic hydrogen evolution
摘要： Honeycomb-like graphitic carbon nitride (HeC3N4) with unique morphology has been studied as a promising polymer photocatalyst. Herein, a novel binary metal sulfide constructed with HeC3N4 (Cd0·5Zn0·5S/HeC3N4) was prepared though the facile in situ precipitation method. The characterization data suggest that Cd0·5Zn0·5S quantum dots (QDs) are well dispersed on the macroporous structure of HeC3N4 (156 m2 g?1), which can provide higher surface area, more catalytic active sites and larger interface contact area with accelerating the migration and separation of charge carriers. By taking advantage of 0D/3D heterojunction structure, the Cd0·5Zn0·5S/HeC3N4 dramatically boosts the photocatalytic H2 evolution rate with the visible-light illumination. The Cd0·5Zn0·5S/HeC3N4-3 yields the highest photocatalytic activity of 5145 mmol h?1 g?1, which is 4.3 times as high as that of pure Cd0·5Zn0.5S. Furthermore, Cd0·5Zn0·5S/HeC3N4 composite presents high stability after four recycles. The enhanced visible-light-driven photocatalytic H2 production is attributed to the construction of n-n type heterojunction as well as the large surface area, which can inhibit the agglomeration of Cd0·5Zn0·5S nanoparticles, and efficiently transfer the photo-excited electron-hole pairs in Cd0·5Zn0.5S. Therefore, this work provides a potential way for designing advanced 0D/3D heterojunction.
关键词： Heterojunction,Honeycomb-like graphitic carbon nitride,Cd0·5Zn0·5S,Photocatalytic hydrogen generation
更新于2025-09-11 14:15:04
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Single titanium-oxide species implanted in 2D g-C3N4 matrix as a highly efficient visible-light CO2 reduction photocatalyst
摘要： A visible-light-response, efficient and robust photo-catalyst for CO2 reduction is highly desirable. Herein, we demonstrate that single titanium-oxide species implanted in two-dimensional (2D) graphitic carbon nitride (g-C3N4) matrix (2D TiO-CN) can efficiently photo-catalyze the reduction of CO2 to CO under the irradiation of visible light. The synergistic interaction between single titanium oxide species and g-C3N4 in 2D TiO-CN not only enhances the separation of photo-excited charges, but also results in visible light response of single titanium-oxide species, realizing high activity of CO2 photo-reduction with extremely high CO generation rate of 283.9 μmol·h?1·g?1, 5.7, 6.8 and 292.2 times larger than those of TiO2/CN hybrid material, CN and commercial TiO2, respectively. Time-resolved fluorescence and electron spin resonance spectroscopy revealed the catalytic mechanism of the fabricated 2D TiO-CN photocatalysts for CO2 reduction.
关键词： two-dimensional (2D) photocatalysts,graphitic carbon nitride,visible-light,single atom catalyst,CO2 reduction
更新于2025-09-11 14:15:04
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One step to prepare CNTs modified porous g-C3N4 with excellent visible-light photocatalytic performance
摘要： A kind of carbon nanotubes (CNTs) modified porous graphitic carbon nitride (CNTs/pg-C3N4) photocatalyst was successfully synthesized via one step thermal polycondensation and completely measured by some instruments, such as XRD, FTIR, TEM, BET, DRS, PL, etc. And the relevant experimental data indicated that loaded CNTs could be beneficial to the photoinduced charges transfer, facilitating photoinduced charge separation rate. Meanwhile, surface area and visible light adsorption of CNTs/pg-C3N4 photocatalyst could be increased and improved. These synergetic effects resulted in the as-synthesized CNTs/pg-C3N4 photocatalyst exhibiting better visible-light-induced photocatalytic performance for organic pollutant degradation and the product of clean energy than bulk g-C3N4, pg-C3N4 and CNTs modified bulk g-C3N4, and excellent stable photocatalytic performance was also observed after several recycling experiments. Finally, a reasonable improved photocatalytic reaction mechanism for CNTs/pg-C3N4 photocatalyst is presented.
关键词： Porous graphitic carbon nitride,Photocatalytic performance,Carbon nanotubes,Photocatalyst,Visible-light
更新于2025-09-10 09:29:36
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Photodegradation of fluazaindolizine in aqueous solution with graphitic carbon nitride nanosheets under simulated sunlight illumination
摘要： The photodegradation of fluazaindolizine (FZDL) under simulated sunlight irradiation was accelerated by the catalysis of graphitic carbon nitride (g-C3N4). Under optimum conditions, such as 5 mg of amount and dispersion, the photodegradation half-life was dramatically enhanced to 2.7 h. More importantly, the pathway of degradation by g-C3N4 was different from both direct photolysis and the catalysis by titanium oxide, with particular negative ions of m/z 221 and 195, corresponding to the cleavage of sulfamide bond and the ring opening of imidazole, respectively. In addition, hydroxyl and superoxide radicals played important roles in photodegradation. The results enriched not only the study of FZDL photodegradation but also the application of g-C3N4. It also suggested the possibility of the water purification by photodegradation for pesticide removal in real life.
关键词： Advanced oxidation processes,Transformation products,Fluazaindolizine,Mass Spectrometery,Photodegradation,Graphitic carbon nitride
更新于2025-09-10 09:29:36
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Dramatically enhanced photoelectrochemical properties and transformed p/n type of g-C3N4 caused by K and I co-doping
摘要： Graphitic carbon nitride (g-C3N4) usually shows amphoteric property in a neutral solution. In this work, a K&I co-doped g-C3N4 is prepared by simply sintering the mixture of dicyandiamine, KI and I2. The K&I co-doping modulates the band structure of g-C3N4 with pulling the Fermi level toward its conduction band minimum. The obtained K&I co-doped g-C3N4 (K&I-C3N4) generates positive photocurrents over the whole investigated potential range, exhibiting a typical n-type semiconductor characteristic. Therefore, the K&I co-doping transforms the g-C3N4 from amphoteric to n-type semiconductor. Also, the prepared K&I-C3N4 shows widened light absorption range and enhanced separation efficiency of the photogenerated charge carriers, which results in the dramatically enhanced photoelectrochemical performance.
关键词： Photoelectrochemical performance,K&I co-doping,Fermi level,p/n type,Graphitic carbon nitride
更新于2025-09-10 09:29:36
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Cobalt oxide loaded graphitic carbon nitride as adsorptive photocatalyst for tetracycline removal from aqueous solution
摘要： The treatment of antibiotic-containing wastewater is of great importance due to the potential threats of antibiotics to human and the ecosystem. We reported the preparation of cobalt oxide loaded graphitic carbon nitride (CoO/g-C3N4) by an impregnation-calcination method for tetracycline (TC) removal from aqueous solution. The developed CoO/g-C3N4 exhibited high adsorption capacity and fast adsorption kinetic for TC due to the complexation of TC with surface loaded CoO. In particular, 7%CoO/g-C3N4-3 sample presented a maximum TC adsorption capacity of 391.4 mg g-1. It was found that Langmuir and pseudo-second order kinetic models fitted TC adsorption process well. Further photocatalytic studies showed that CoO loaded g-C3N4 was active for TC photodegradation, although the photocatalytic reaction rate constant was lower than that of native g-C3N4. CoO nanoparticles loading on g-C3N4 played the major role of adsorption sites rather than cocatalyst for photocatalysis. We believe that the developed CoO/g-C3N4 could be a potential adsorptive photocatalyst for antibiotic pollutants removal from wastewater.
关键词： Graphitic carbon nitride,antibiotic,photocatalysis,adsorption,cobalt oxide
更新于2025-09-10 09:29:36
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Construction of acetaldehyde-modified g-C3N4 ultrathin nanosheets via ethylene glycol-assisted liquid exfoliation for selective fluorescence sensing of Ag+
摘要： We successfully prepared acetaldehyde-modified g-C3N4 ultrathin nanosheets (ACNNSs) by a simple ethylene glycol-assisted liquid exfoliation method. The introduction of acetaldehyde regulated the surface energy of g-C3N4 to better match with that of water, which improved the exfoliation efficiency. Moreover, the acetaldehyde introduces defects into the g-C3N4 structure, which can act as excitation energy traps and cause considerable variation in the fluorescence emission. Benefiting from the stable photoluminescence (PL) emission, good water solubility and biocompatibility, the obtained ACNNSs showed a selective fluorescent response to Ag+ both in aqueous solution and living cells. The strong absorption and intimate contact with Ag+, and its appropriate redox potential of ACNNSs contributed to this excellent fluorescent response. A simple and environmental friendly approach was proposed to simultaneously achieve modification and exfoliation of g-C3N4 in aqueous solution. These findings might lead to wider applications of carbon-based nanomaterials as active materials for fluorescence detection in the environment.
关键词： Graphitic carbon nitride nanosheets,Living-cell imaging,Glycol-assisted exfoliation,Fluorescent sensor,Acetaldehyde-modified,Ag+
更新于2025-09-10 09:29:36