CHINESE CHEMICAL LETTERS
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2020
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IF 4.632
Sijia Sun,Hao Ding,Lefu Mei,Ying Chen,Qiang Hao,Wanting Chen,Zhuoqun Xu,Daimei Chen
Using low-cost precipitated silica (SiO 2 ) as the carrier, a ternary SiO 2 -TiO 2 /g-C 3 N 4 composite photocatalyst was prepared via the sol-gel method associated with a wet-grinding process. The as-prepared composite exhibits photocatalytic hydrogen production and pollutant degradation performance under solar-like irradiation. The effect of SiO 2 carrier on the properties of the heterostructure between TiO 2 and g-C 3 N 4 (CN) was systematically studied. It is found that SiO 2 has important effects on promoting the interaction between TiO 2 and CN. The particle size of TiO 2 and CN was obviously reduced during the calcination process due to the effects of SiO 2 . Especially, the TiO 2 particles exhibit monodispersed state with particle size below 10 nm (quantum dots), resulting in the improvement of the contact area and the interaction between TiO 2 and CN, and leading to the formation of efficient TiO 2 /CN Z-scheme heterostructure in SiO 2 -TiO 2 /CN. Besides, the introduction of SiO 2 can increase the specific surface area and light absorption of SiO 2 -TiO 2 /CN, further promoting the photocatalytic reaction. As expected, the optimum SiO 2 -TiO 2 /CN composite exhibits 12.3, 3.1 and 2.9 times higher photocatalytic hydrogen production rate than that of SiO 2 -TiO 2 , CN and TiO 2 /CN under solar-like irradiation, while the photocatalytic active component in SiO 2 -TiO 2 /CN is only about 60 wt%. Moreover, the rhodamine B degradation rate of SiO 2 -TiO 2 /CN is also higher than that of SiO 2 -TiO 2 , CN and TiO 2 /CN.
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高影响因子
Journal of Energy Chemistry
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2020
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IF 7.216
Zhanghui Xie,Shan Yu,Xiang-Bing Fan,Shiqian Wei,Limei Yu,Yunqian Zhong,Xue-Wang Gao,Fan Wu,Ying Zhou
Photocatalytic splitting of hydrogen sulfide (H 2 S) for hydrogen evolution is a promising method to solve the energy and environmental issues. In this work, S,N-codoped carbon dots (S,N-CDs)/graphitic carbon nitride (g-C 3 N 4 ) nanosheet is synthesized by hydrothermal method as an efficient photocatalyst for the decomposition of H 2 S. In addition to the characterization of the morphology and structure, chemical state, optical and electrochemical performances of S,N-CDs/g-C 3 N 4 , hydrogen evolution tests show that the activity of g-C 3 N 4 is improved by introducing S,N-CDs, and the enhancement depends strongly on the wavelength of incident light. The photocatalytic hydrogen production rate of S,N-CDs/g-C 3 N 4 composite reaches 832 μmol g −1 h −1 , which is 38 times to that of g-C 3 N 4 under irradiation at 460 nm. Density functional theory calculations and electron paramagnetic resonance as well as photoluminescence technologies have altogether authenticated that the unique wavelength-dependent photosensitization of S,N-CDs on g-C 3 N 4 ; meanwhile, a good match between the energy level of S,N-CDs and g-C 3 N 4 is pivotal for the effective photocatalytic activity. Our work has unveiled the detailed mechanism of the photocatalytic activity enhancement in S,N-CDs/g-C 3 N 4 composite and showed its potential in photocatalytic splitting of H 2 S for hydrogen evolution.
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JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
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2020
·Vol. 35
·期 1
·99-106
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IF 0.64
Su Junzhang,Wu Xiangfeng,Zhang Chenxu,Wang Hui,Zhang Mi,Zhang Jiarui,Jia Yunning,Cui Yanan,Tong Xin,Shang Jialu,Zhang Chenyu
The CdS/ spherical g-C 3 N 4 n-n heterojunction photocatalyst was fabricated via a solvothermal method. The tetracycline was used to characterize the photocatalytic properties of the as-developed hybrids. The photocatalytic degradation mechanism of the as-developed heterojunction photocatalyst was also analyzed. Research results show that CdS nanoparticles are well dispersed in the surface layer of spherical g-C 3 N 4 . Moreover, the mass ratio of CdS to spherical g-C 3 N 4 will influence the photocatalytic activity of the asdeveloped composites, which shows the trend of first increasing and then decreasing as it increased. When the mass ratio is 7:1, in 25 min, the as-developed heterojunction shows 93.2 % of the maximum photocatalytic efficiency and still exhibits 83.6 % after 5 times cycle testing. Moreover, the as-developed hybrids can accelerate the electron transport and improve the separation efficiency of photo-generated carriers compared with pure samples. In addition, the holes and superoxide radicals are dominating active species during the photocatalytic degradation process.
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CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Yin Wang,Ruotong Wang,Lan Yu,Yun Wang,Chuanhui Zhang,Xiaodong Zhang
A series of new layered composite catalysts LaCu 0.5 Co 0.5 O 3 -MMT 0.2 /CN x (x = 0.025, 0.075, 0.125) were prepared by montmorillonite (MMT) and g-C 3 N 4 (CN) in situ intercalation of B-site double perovskite. The experimental results showed that the appropriate MMT and CN loading of LaCu 0.5 Co 0.5 O 3 -MMT 0.2 /CN 0.075 were beneficial to the increase of catalytic performance because perovskites were evenly distributed between the layers of MMT and CN and effectively avoided the loss of active components. The sample had a smaller particle size distribution, a larger specific surface, a higher ratio of O ads /O latt and excellent microwave absorption capabilities. The removal rate reached 98.7% in 6 min under optimal conditions with catalyst dosage of 9.5 g/L, H 2 O 2 dosage of 350 μL, pH of 4, MW power of 500 W, and bisphenol A (BPA) concentration of 50 mg/L. LCCOM 0.2 /CN 0.075 also showed good reusability with a degradation efficiency of 95.7% even after the 5th cycle. And the microwave-catalyzed degradation followed pseudo first-order kinetics. Combining relevant characterization and experimental results of free radical capture, possible reaction mechanisms were discussed. The surface active sites of the catalyst can be excited by microwaves to produce oxidized free radicals, thereby degrading bisphenol A through electron-hole transport.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
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IF 4.65
Huaji Pang,Yunhong Jiang,Wensheng Xiao,Yanhuai Ding,Cai Lu,Zhanpeng Liu,Ping Zhang,Hean Luo,Wei Qin
g-C 3 N 4 and CdS have attracted intense attention in the field of energy and environment research. Cubic-phase CdS possesses a smaller bandgap than that of hexagonal CdS but has seldom been used as photocatalytic material. This work focuses on the photocatalytic H 2 generation of few-layer g-C 3 N 4 nanosheets (CNS) anchored with cubic-phase CdS nanocrystals (CNS–CdS). The CNS–CdS composites were synthesized by depositing cubic-phase CdS on the surface of CNS in a sulfur-rich solution. Owing to the large specific surface area, rich active sites and strong synergy between cubic CdS and g-C 3 N 4 nanosheets, the CNS–CdS showed the enhanced light absorption and separation of the photo-generated carriers, which endowed it with superior H 2 generation activity and stability. The optimal average hydrogen production rate of the CNS–CdS photocatalyst reached to 2.24 mmol∙h −1 ·g −1 under irradiation of AM 1.5G, which was 3.5 and 3.3 times of that of cubic CdS and few-layer g-C 3 N 4 nanosheets, respectively. The best apparent quantum efficiency at 475 nm reached up to 13.83%, and the maximum conversion efficiency of incident photon-to-current is 59.6% in the wavelength range of 350–700 nm. The excellent stability of the as-prepared CNS–CdS was also proven by the cyclic run. The results suggest the replacement of hexagonal CdS with cubic CdS result in energy-saving, performance-stable and high-efficient photocatalytic materials.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
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IF 4.65
Yunlong Zhou,Dongyao Lin,Xiaoyuan Ye,Mingyuan Zhu
In this study, sulfur-doped Ni(OH) 2 was prepared by an immersion method at room temperature and used as an efficient co-catalyst for g-C 3 N 4 in photocatalytic hydrogen evolution . The structure, morphology, and elemental composition of the sulfur-doped Ni(OH) 2 /g-C 3 N 4 were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy , and X-ray photoelectron spectroscopy. These results proved that the sulfur-doped Ni(OH) 2 was successfully synthesized and combined with g-C 3 N 4 at the heterojunction . The photocatalytic hydrogen generation results of Ni(OH) 2 /g-C 3 N 4 (0 μmol g −1 h −1 ) and that of sulfur-doped Ni(OH) 2 /g-C 3 N 4 (1573.7 μmol g −1 h −1 ) indicate that the sulfur doping resulted in significant improvement in the catalytic activity of co-catalyst Ni(OH) 2 . Moreover, the possible mechanism of photocatalytic hydrogen evolution catalyzed by the sulfur-doped Ni(OH) 2 /g-C 3 N 4 was proposed. The results of photoluminescence , ultraviolet–visible diffuse reflectance spectroscopy , and electrochemical analysis demonstrated that the sulfur doping provided more active sites in Ni(OH) 2 , leading to the efficient hydrogen evolution reaction, thus indirectly enhancing the separation efficiency of electron–hole pairs and the migration efficiency of photogenerated electrons by the photocatalyst g-C 3 N 4 .
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JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Yu Zhou,Long Zhou,Chunhua Ni,Enhui He,Liangmin Yu,Xia Li
A new MOF-derived CoCeOx nanosphere/g-C 3 N 4 nanosheet composite material with a high specific surface area, compact interface, abundant active sites, and promotion of electron transfer and separation was successfully prepared. The prepared 10% CoCeOx/g-C 3 N 4 composite material generated hydrogen with an efficiency of 1050 µmol g −1 h −1 under visible light irradiation, and 97% of carbamazepine was degraded in 1 h at a degradation rate of 0.05 min −1 with the help of PDS. Based on DFT calculations and mass spectrometry analysis , the degradation products and degradation pathways of carbamazepine were also proposed. According to tests of the photocatalytic properties, SO 4 -• , h + ,•OH, and •O 2 - were produced by the composite itself; these species play an important role in the degradation. The photocatalytic mechanism was also proposed. The prepared CoCeOx/g-C 3 N 4 composite material provides a simple and effective strategy for energy utilization and wastewater treatment.
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LANGMUIR
·
2021
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IF 3.882
Yan Xiong,Can Zhang,Ming Duan,Jie Chen,Shenwen Fang,Jun Li,Peng Shi,Jintian Ren,Haiqin Wan
Herein the adsorption characteristics of zwitterionic dye pollutant Rhodamine B (Rh+B–) on a g-C3N4 surface were investigated by both an attenuated total reflection spectroscopy (ATRS) experiment and a molecular dynamics simulation (MDS). For experimental investigation, g-C3N4 was coated on a silica optical fiber (SOF) surface to fabricate an adsorption film. According to the ATRS response, adsorption thermodynamics and thermodynamics results were in situ obtained and evaluated. The isothermal Langmuir model was used to calculate the adsorption equilibrium constants (Kads) and adsorption energies (ΔGads) for Rh+B– as 27.25 × 104 M–1 and −31.01 kJ mol–1, respectively, which indicated the spontaneous adsorption behavior of Rh+B– at the g-C3N4 surface. Using dynamic Elovich modeling, the rate constants of Rh+B– were found to be k1 = 0.0063 min–1 and k2 = 0.0004 min–1, which indicated two-stage adsorption at the g-C3N4 surface. For theoretical simulation, adsorption configurations and adsorption energies were systematically calculated by a molecular dynamics simulation (MDS) . Rh+B– molecules were inclined to orient in a parallel position at the g-C3N4 surface during low concentration but a perpendicular position at the g-C3N4 surface during high concentration. Combined with experimental and calculation results, this work revealed the microscopic adsorption performance and elucidated the intermolecular interaction between localized interfaces of g-C3N4 and hazardous dye pollutant. We propose an adsorption model to explain the process of surface interaction, which is based on molecular orientation and a force-driven mechanism. Electrostatic attraction and π–π interaction dominated the adsorption interaction with an adsorption energy of ΔGlow(ads) = −38.96 kJ mol–1 for low Rh+B– concentration, and electrostatic attraction dominated the adsorption interaction with an adsorption energy of ΔGhigh(ads) = −25.76 kJ mol–1 for high Rh+B– concentration. This work can provide a fundamental basis for a dye-pollutants removal application by g-C3N4 in both adsorption and photocatalyzation.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Ning Liu,Na Lu,HongTao Yu,Shuo Chen,Xie Quan
In recent years, the excellent performance of sulfate radical (SO 4 · − ) in advanced oxidation process has attracted more and more attention. However, it requires the consumption of expensive persulphate (PMS/PDS), and the resulting sulfate ion (SO 4 2− ) requires subsequent processing procedures, which limits its practical application value. In this work, a Z-scheme heterojunction g-C 3 N 4 /BiPO 4 (CNB x ) photocatalyst was constructed to in-situ activate the residual SO 4 2− , H 2 O and dissolved O 2 in organic wastewater simultaneously and produce SO 4 · − , ·OH and O 2 · − efficiently, so as to realize enhanced organic pollutant treatment by using clean and renewable solar energy resources. Under the condition of 10 mM SO 4 2− addition and 100 mW·cm −1 illumination, the degradation rate of BPA ( C 0 = 20 mg·L −1 ) by optimized CNB 150 catalyst was 0.30 min −1 , which was 50% higher than that without SO 4 2− (0.20 min −1 ). Detailed characterizations shown that a direct Z-scheme heterojunction was formed between g-C 3 N 4 and BiPO 4 , which could be simultaneously stimulated by light, and then effective charge separation and migration could be achieved through the internal electric field caused by the Fermi-level difference between the g-C 3 N 4 (-0.12 eV) and BiPO 4 (0.01 eV). In general, this study makes full use of renewable solar energy and provides a feasible path for promoting the simultaneous in-situ utilization of small molecules (SO 4 2− , H 2 O and O 2 ) that originally exist in water, which makes organic wastewater treatment more economic, eco-friendly and sustainable.
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Environmental Progress & Sustainable Energy
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2021
·Vol. 41
·期 1
·e13714
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IF 2.431
Xiaowei Wang,Junkai Zhang,Fengmin Wu,Junqing Cai,Jie Luo,Erpeng Zhou,Yongping Niu
Graphitic carbon nitride (g-C 3 N 4 ) is a fascinating nonmetallic photocatalyst for the removal of environmental pollutants. The fumed silica/g-C 3 N 4 (gCN-FS) composite photocatalysts were successfully fabricated by a combination of solvent volatilization and post-annealing methods. The introduction of SiO 2 not only widens the absorption range of visible light, but also enhances the specific surface area of g-C 3 N 4 . The gCN-FS-3 composite has a BET surface area of 129.89 m 2 /g, which is ~3.3 times as much as that of g-C 3 N 4 (39.54 m 2 /g). The gCN-FS composites have markedly improved rhodamine B (RhB) photodegradation activity in comparison to pure g-C 3 N 4 , bulk g-C 3 N 4 and P25 under 557 nm yellow-green light emitting diode light irradiation. The gCN-FS-3 has the highest RhB photodegradation rate, which is ~9.67-, 11.81-folds as compared to bare g-C 3 N 4 and bulk g-C 3 N 4 , respectively. The coupling effect between the increase in specific surface areas and the inhibition effect of SiO 2 on photogenerated electron/hole pairs recombination is responsible for the enhanced visible light photocatalytic activity of gCN-FS composite. Superoxide and holes are responsible for the RhB photocatalytic degradation. Furthermore, no apparent loss of photocatalytic activity over five cycles is observed, which indicates that the gCN-FS composites have considerable stability and reusability in the photodegradation process. The gCN-FS composites show great promise in visible light driven photocatalysis for environmental applications.
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2021
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IF 8.067
Yiqian Lv,Yueqing Zheng,Honglin Zhu,Yinghao Wu
As a semiconductor material with a 2D-laminate structure, g-C 3 N 4 (bandwidth 2.7 eV) has a similar structure and excellent performance to graphene. However, high surface energy and photogenerated e–h recombination of g-C 3 N 4 seriously hinder its application in the field of marine anticorrosion and antifouling. To solve these problems, we synthesized the g-C 3 N 4 nanosheets decorated with ZnO nanoring via chemical etching technology. Whether the NR ZnO-CNNs have surface protection performance among the pure EP on the corrosion protection for metal substrate were investigated. The antifouling properties NR ZnO-CNNs hybrid were also estimated through photocatalytic bacterial and algae resistance tests. Combined with the electrochemical results, it was found that the impedance modulus of NR ZnO-CNNs/EP within 45 days showed two orders of magnitude higher than that of pure EP in the 3.5 wt% NaCl solution. Besides, Local electrochemical impedance spectroscopy (LEIS) further explored the anticorrosion behavior of NR ZnO-CNNs/EP coating, which indicated that the NR ZnO-CNNs/EP coating with a scratch maintained an excellent corrosion resistance between 0–24 h. Under the visible light conditions, the lifetime of photogenerated e–h was prolonged due to the formation of NR ZnO-CNNs heterojunction structure, it was observed that the antibacterial rate against Bacillus subtilis reached 100% within 8 h. An Antialgae test was performed on chlorella seawater solution, which indicated that 5 mg/mL of NR ZnO-CNNs hybrid could make chlorella sharply reduce within 4 days. Simultaneously, the corrosion protection and photocatalytic antifouling mechanisms of NR ZnO-CNNs were proposed, thus it provided a broader platform for the design of versatile marine protection materials.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
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IF 4.175
Wei Wang,Jiaojiao Fang,Hu Chen
Mesoporous materials offer attractive routes for designing photocatalysts with nano-confined structures, high activities, and recyclability. Here we take the core-shell and mesoporous SiO 2 nanoparticles as the template for the in situ synthesis of nano-confined g-C 3 N 4 with controllable structures and quantum size effects by varying the precursor species and concentrations. Results indicate that decrease the cyanamide, the precursor, concentration will improve the specific surface area, adsorption ability, and quantum size effect of the final photocatalysts. Cyanamide aqueous solution with a weight ratio of 50.0 wt% results in the most active photocatalyst containing 31.17 wt% of the confined g-C 3 N 4 with a tetracycline degradation rate of 6.63 times higher than that of the cyanamide-derived bulk g-C 3 N 4 (C) under the xenon lamp irradiation. Replacing the cyanamide with urea can further improve the photocatalytic activity even the more active SiCN(U10) contains only 12.47 wt% of the confined g-C 3 N 4 . The improved photocatalytic activity is resulted from the synergistic effects of the high adsorption ability, low aggregation, enhanced quantum size effect, and more exposed active sites. The present study gives new sight on improving the aqueous phase recyclability of the few-layered and high-reactive g–C 3 N 4 –based photocatalysts, and may promote its industrial application process.
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