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Synthesis of C3N4-decorated ZnO and Ag/ZnO nanoparticles via calcination of ZIF-8 and melamine for photocatalytic removal of methyl orange
摘要： The C3N4-decorated ZnO and Ag/ZnO nanoparticles were prepared using melamine and ZIF-8 as precursors after thermal treatment under air condition. The results from the structural analysis suggested that the presence of the metallic Ag as well as C3N4 in the composite and the introduction of the melamine could slightly enhance the aggregation of the particles of the three dimensional structure of ZnO and Ag/ZnO. However, the presence of C3N4 and Ag could boost the utilization of the light and increase the separation of electrons and holes. Finally, the photocatalytic degradation of methyl orange indicated that the C3N4-decorated ZnO and Ag/ZnO displayed an enhanced ability in comparison with pure ZnO and C3N4, which suggested that the synergistic effect of Ag and C3N4 played an important role in the catalytic process.
关键词： Photocatalytic degradation,ZIF-8,C3N4,Synergistic effect,Ag/ZnO composites
更新于2025-09-04 15:30:14
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Carbonyl linked carbon nitride loading few layered MoS2 for boosting photocatalytic hydrogen generation
摘要： Pristine graphitic carbon nitride g-C3N4 materials, as a novel metal-free photocatalyst with moderate activity, have attracted intense interest. However, its fast photogenerated carriers recombination always induces a relative low performance. Herein, we for the first time report one new =C=O group linked g-C3N4 (CO-C3N4) through CO2-assisted thermal polymerization of urea. It is found that the edge =C=O groups work as the photogenerated electrons collection sites, and then promote the carriers separation. The visible-light phototatalytic hydrogen evolution performance of our synthesized samples shows 1.85 times higher than that of the reference g-C3N4. To get a considerable visible-light driven photocatalytic hydrogen generation, a new few layered MoS2 with a small size (ca. 20 nm) is prepared through a liquid exfoliation, and then is loaded onto the CO-C3N4. The optimal MoS2/CO-C3N4 sample gives the photocatalytic hydrogen evolution of 1990 and 1440μmol/(g*h) under the λ > 400 and λ > 420 illumination, higher than the reported values in literatures. The sample also shows a considerable excellent photocatalytic activity of 44.3 μmol/(g*h) under LED-600 condition.
关键词： water splitting,CO-C3N4,MoS2,photocatalysis,H2 generation
更新于2025-09-04 15:30:14
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Au-loaded porous g-C<sub>3</sub>N<sub>4</sub> nanosheets for enhanced photocatalytic IPA degradation under visible-light irradiation
摘要： A series of Au-loaded porous g-C3N4 nanosheets were prepared by anchoring Au nanoparticles onto g-C3N4 surfaces. The as-prepared samples were characterized via XRD, FTIR, TEM, BET, PL, and UV-visible measurements, respectively. The activities of Au/g-C3N4 composites were evaluated by the photocatalytic degradation of gaseous isopropyl (IPA) under visible-light illumination. The results indicated that 2% Au/g-C3N4 exhibited the highest photocatalytic efficiency of gaseous IPA oxidation (11.51 ppm/min), which was 2.4 times higher than that of pure g-C3N4 nanosheets. The remarkable photodegradation efficiency derived from the promoted photoinduced carriers separation and larger specific surface area. For one thing, the ultrathin mesoporous g-C3N4 nanosheets provided abundant reactive sites and facilitated electron diffusion. For another, the localized surface plasmon resonance (LSPR) and electron-sink effect of Au particles significantly suppress the recombination of the photoinduced holes and electrons. Therefore, the deposition of Au nanoparticles with porous g-C3N4 nanosheets could be regarded as an efficient way to enhance the photocatalytic activity of gaseous IPA pollutant removal.
关键词： nanosheet,photocatalysis,g-C3N4,Au loading,IPA
更新于2025-09-04 15:30:14
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Enhancement of visible‐light photocatalytic hydrogen production by CeCO3OH in g‐C3N4/CeO2 system
摘要： Promoting the separation of photo-generated carriers is significantly important to improve the efficiency of photocatalytic hydrogen production. Therefore, we prepared g-C3N4/CeCO3OH/CeO2 (CeCeCN) ternary nanocomposite via an easy synthetic way using g-C3N4 and CeO2 as reactants. A CeCO3OH layer was formed and resulted in the novel ternary photocatalyst. The CeCeCN composite shows superior photocatalytic (PC) H2 generation performance in sunlight excitation. The H2 evolution rate is about 764 μmol h-1 g-1, which is over 11 times larger than those of g-C3N4 and CeO2. Compared with g-C3N4 and CeO2, CeCeCN further shows a larger photo-response current density and a lower charge-transfer resistance. The remarkably increased photocatalytic property of CeCeCN is because of the efficient charge migration induced by the formed heterojunction. Our findings demonstrate that building multi-heterostructures can liberate more excited electrons for efficient hydrogen production under sunlight.
关键词： heterojunction,CeCO3OH,g-C3N4/CeCO3OH/CeO2,photocatalytic hydrogen evolution,ternary
更新于2025-09-04 15:30:14
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A Metal‐Organic‐Framework‐Derived g‐C3N4/α‐Fe2O3 Hybrid for Enhanced Visible‐Light‐Driven Photocatalytic
摘要： As one of the most efficient systems for photocatalytic hydrogen evolution, the Z-scheme system consisting of different semiconductors with a reversible donor-acceptor pair has attracted great attention. Considering for the nontoxicity and low cost of photocatalysts, a series of g-C3N4/α-Fe2O3 hybrids were rationally constructed based on the Z-scheme mechanism for the first time using a metal-organic framework template approach that can fine-tune the compositions and properties of the hybrids. An optimized hybrid, g-C3N4/α-Fe2O3-2, exhibited prominent photocatalytic water splitting performance with a visible light response. Under irradiation of visible light (λ > 420 nm), the hybrid shows a high durability and superior hydrogen production rate of 2066.2 μmol g-1 h-1 from water splitting, which is approximately three times greater than that of bulk g-C3N4 because of the effective separation of photo-excited charge carriers by two narrow bandgap semiconductors tightly coupled with the Z-scheme structural feature.
关键词： Z-scheme system,hydrogen evolution,g-C3N4/α-Fe2O3 hybrid,metal-organic frameworks
更新于2025-09-04 15:30:14
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Rapid fabrication of KTa0.75Nb0.25/g-C3N4 composite via microwave heating for efficient photocatalytic H2 evolution
摘要： A novel KTa0.75Nb0.25O3 (KTN)/g-C3N4 composite photocatalyst was fabricated through microwave heating for realizing the e?cient photocatalytic H2 evolution. The energy-e?cient preparation method allowed g-C3N4 to be formed in-situ on KTN surface in thirty ?ve minutes. The binary constitution of the KTN/g-C3N4 composite was veri?ed by X-ray di?raction (XRD) and X-ray photoelectron spectroscopy (XPS) experiments. UV–visible di?use re?ection spectroscopy (DRS) experiments suggested that the photoabsorption performance was increased after the introduction of KTN. N2-adsorption analysis indicated that the addition of KTN slightly increased the surface area of g-C3N4. Photoluminescence (PL) spectroscopy, electrochemical impedance spectroscopy (EIS) and transient photocurrent response (PC) analyses con?rmed that the KTN/g-C3N4 composite displayed longer lifetime of photoexcited charge carriers than g-C3N4, owing to the suitable band potentials and the close contact of KTN and g-C3N4. This property was believed to the key characteristic of the composite, which led to its excellent photocatalytic performance. Under simulated sunlight irradiation, the optimal KTN/g-C3N4 catalyst presented a photocatalytic H2-generation rate of 1673 μmol·g?1·h?1, 2.5 and 2.4 times higher than that of KTN and pure g-C3N4, respectively. Under visible light irradiation, the value was determined to be 86.2 μmol·g?1·h?1, which achieved 9.3 times that of g-C3N4.
关键词： Microwave heating method,KTa0.75Nb0.25O3,Photocatalytic H2 evolution,g-C3N4
更新于2025-09-04 15:30:14
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One-step synthesis of petals-like graphitic carbon nitride nanosheets with triazole defects for highly improved photocatalytic hydrogen production
摘要： Reaction atmospheres during graphitic carbon nitride preparation can have a significant influence on the chemical composition and structure of the material, subsequently improving the photocatalytic activity. However, it is still a challenge to introduce an atmosphere by one-step heat-treated method to synthesis graphitic carbon nitride without additive gases. Herein, we developed a new one-step method to gather a variety of gases for preparing petals-like graphitic carbon nitride nanosheets (CNeC), such as CO(g), NH3(g) and H2O(g). NH3(g) and H2O(g) are respectively derived from melamine-cyanuric acid supermolecule during pyrolysis. The petals-like CNeC with more triazole defects (Nc) significantly increases the separation efficiency and the mobility of photogenerated photo-induced electron-hole pairs. Compared with the g-C3N4 calcined under nitrogen atmosphere (CNeN), CNeC has smaller grain, higher porosity with larger surface area, and remarkably longer lifetime of charge carriers. As expected, the product CNeC exhibited a hydrogen evolution rate of 1334 mmol g?1 h?1 under visible-light irradiation, which was 2.8 times higher activity than CNeN, as well as higher than most of the reported bulk g-C3N4.
关键词： Photocatalysis,g-C3N4,Triazole defects,Multiple gases,Hydrogen evolution
更新于2025-09-04 15:30:14
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Synthesis g-C <sub/>3</sub> N <sub/>4</sub> of high specific surface area by precursor pretreatment strategy with SBA-15 as a template and their photocatalytic activity toward degradation of rhodamine B
摘要： Using SBA-15 as a template, high surface area porous graphitic carbon nitrides (g-C3N4) were successfully synthesized by pretreating melamine using hydrochloric acid, and fully characterized by Fourier-Transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron micrographs (SEM), N2 adsorption-desorption, ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL) spectrum. The results of these analyses indicated that the g-C3N4 synthesized from HCl-pretreated melamine with SBA-15 as a template has enhanced specific surface area and increased the separation rate of the photogenerated electrons and holes compared with bulk g-C3N4, but didn’t change the structure of bulk g-C3N4. The photocatalytic activity of samples was evaluated by the degradation of rhodamine B (RhB) under xenon lamp. The results indicated that the activity was improved significantly with the increase of specific surface area. The rate constant for CN-3（ HCl pretreatment melamine precursor and SBA-15 as a template） was 13 times as high as g-C3N4. Furthermore, the CN-3 catalyst exhibited outstanding structural and catalytic stability.
关键词： precursor pretreatment strategy,SBA-15 template,g-C3N4,Degradation of RhB,high surface area
更新于2025-09-04 15:30:14
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Green synthesis of g-C <sub/>3</sub> N <sub/>4</sub> -Pt catalyst and application to photocatalytic hydrogen evolution from water splitting
摘要： The g-C3N4-Pt photocatalyst was successfully prepared by the combination of a biosynthesis method and sol deposition, which were used for hydrogen evolution from water splitting. The layers of g-C3N4 are thinned and the Pt nanoparticles simultaneously become tightly bound to g-C3N4 by secondary calcination in the process of synthesizing the g-C3N4-Pt photocatalyst. Analysis of the morphological structure and instrumental characterization of the optical performance revealed that the Pt nanoparticles were successfully loaded and well dispersed on the surface of g-C3N4. Furthermore, the absorption wavelength range of the g-C3N4-Pt photocatalyst in visible light was widened and the absorption increased. The activity and photostability of the g-C3N4-Pt photocatalyst for hydrogen evolution under visible light irradiation (λ≥420 nm) were excellent. The rate of H2 evolution reached 582.4 mmol h?1 g?1, and the quantum efficiency (QE) reached 2.70% at 420 nm.
关键词： green synthesis,hydrogen evolution,visible-light photocatalysis,G-C3N4-Pt photocatalyst
更新于2025-09-04 15:30:14
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Facial synthesis of a novel Ag <sub/>4</sub> V <sub/>2</sub> O <sub/>7</sub> /g‐C <sub/>3</sub> N <sub/>4</sub> heterostructure with highly efficient photoactivity
摘要： A novel Ag4V2O7/g-C3N4 heterostructure was synthesized by a facial etching method in ammonia solution using Ag2VO2PO4/g-C3N4 as a self-sacrifice precursor. With the concentration of ammonia solution increasing from 0.05 to 0.2 M, phase transformation took place, described as: Ag2VO2PO4/g-C3N4 → Ag2VO2PO4/Ag4V2O7/g-C3N4 → Ag4V2O7/g-C3N4. Compared with pristine Ag2VO2PO4/g-C3N4, the etched samples of Ag4V2O7/g-C3N4 and Ag2VO2PO4/Ag4V2O7/g-C3N4 exhibited dramatically improved activity for the degradation of methylene blue (MB), methyl orange (MO) and imidacloprid under visible light irradiation. When etched with 0.15 M ammonia solution, an Ag4V2O7/g-C3N4 heterostructure was obtained that exhibited the highest photoactivity. This photocatalyst was nearly 9.1, 3.0, and 24.3 times more efficient than pristine Ag2VO2PO4/g-C3N4 for degradation of MB, MO and imidacloprid, respectively. The excellent photocatalytic performance can be ascribed to the as-obtained well-defined Ag4V2O7/g-C3N4 heterojunction, which improves the separation and transfer efficiency and prolongs the lifetime of photoinduced charges. In addition, the stability and dominant radicals were investigated.
关键词： photocatalyst,heterostructure,Ag4V2O7/g-C3N4,visible light
更新于2025-09-04 15:30:14