共查询到20条相似文献,搜索用时 15 毫秒
1.
A novel and simple in situ synthetic strategy was used to fabricate CdS/g-C3N4 hybrid nanocomposite catalysts with visible-light-driven photocatalytic activity from cadmium-containing carbon nitride compounds. X-ray diffraction measurements, high-resolution transmission electron microscopy images, and Fourier transform infrared spectra showed heterojunctions with a close interface between the g-C3N4 and the CdS nanoparticles and nanorods in the composite. Ultraviolet visible diffuse reflectance spectra exhibited a red shift that further presented the CdS in the polymer g-C3N4 skeleton, which allowed the efficient utilization of the solar spectrum for creating photogenerated electrons and holes. The photoluminescence spectra of the nanocomposites suggested charge transfer from g-C3N4 to CdS. The photocurrent intensity of hybrid nanocomposites was 2.3 times than that of pure g-C3N4 sample, and photocatalytic activity for the photodegradation of methyl orange was 2.5 times, and hydrogen evolution reaction was 2.8 times. Enhanced photocatalytic activity and photocurrent for the CdS/g-C3N4 hybrid nanocomposites were achieved. 相似文献
2.
Novel Bi12TiO20/g-C3N4 composite was successfully prepared with Bi12TiO20 nanoparticles embedded within the fluffy crumpled g-C3N4 nanosheets. Bi12TiO20/g-C3N4 composites exhibit superior photoactivity and stability. As compared with g-C3N4 and Bi12TiO20, the photocatalytic efficiency of Bi12TiO20/g-C3N4 is effectively enhanced about 1.8- and 4.9-fold, respectively. Based on the trapping experiment, ·OH and ·O2? radicals are the dominant reactive oxygen species involved in the photocatalytic process. The proposed Z-scheme mechanism of charge transfer markedly promotes the carriers’ migration and separation, leading to the enhanced photocatalytic performance. 相似文献
3.
Wenyu Gao Yang Zhao Zhiyong Mao Dasen Bi Jingjing Chen Dajian Wang 《Journal of Materials Science》2018,53(13):9473-9485
In this paper, g-C3N4/SnO2:Sb composite photocatalysts were fabricated by in situ loading Sb-doped SnO2 (SnO2:Sb) nanoparticles on graphitic carbon nitride (g-C3N4) nanosheets via a facile hydrothermal method. The synthesized g-C3N4/SnO2:Sb composites delivered enhanced visible light photocatalytic performance for degradation of rhodamine B in comparison with g-C3N4/SnO2 composites without doping Sb. Various techniques including XRD, SEM, TEM, FTIR, XPS, PL and electrochemical method were employed to demonstrate the successful fabrication of g-C3N4/SnO2:Sb composite and to investigate the enhanced mechanism of photocatalytic activity. The improvement of visible light absorption and the promotion of separation efficiency and interfacial transfer of photogenerated carriers induced by Sb doping were responsible for the enhancement of photocatalytic activity. This study provides a simple and convenient method to synthesize a visible light responsive catalyst with promising performance for the potential application in environmental protection. 相似文献
4.
In situ fabrication of TiO2/g-C3N4 (TCN) heterojunctions was achieved by a modified sol-gel method. TG analysis was employed to determine the content of TiO2 in TCN composites. XRD, FTIR, TEM and HRTEM were used to analyze the phase composition, functional groups, morphology and microstructure of as-obtained products, respectively. Based on the measurement of surface Zeta potential of g-C3N4, a possible mechanism on in situ fabrication of TCN heterojunctions was concluded. The control experiments indicated that TCN heterojunctions exhibited better photocatalytic performance than either TiO2 or g-C3N4, suggesting that the enchanced photocatalytic activity could be realized by TCN heterojunctions. Then, the evaluation of parameters affecting the photocatalytic performance of TCN heterojunctions was investigated. Even after five cycles, TCN heterojunctions still maintained high photocatalytic activity, exhibiting the good photocatalytic stability. UV-vis absorption spectra showed that almost all MB molecules were decomposed in the photocatalytic process. Finally, the possible mechanism on enhanced photocatalytic performance of TCN heterojunctions was discussed. 相似文献
5.
This article reported a well-organized 3D urchin-like hierarchical TiO2 which was synthesized by a simple solvothermal method without using any template or surfactant. The results of scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and powder X-ray diffraction showed that the hierarchical morphology and size of TiO2 could be effectively controlled by adjusting the precursor ratio of tetrabutyl titanate to TiCl4 solution, the concentration of TiCl4 solution, the solvothermal temperature, and the reaction time. It is believed that the formation of the urchin-like hierarchical TiO2 followed a ‘nucleation–self-assembly–dissolution-recrystallization’ growth mechanism. In addition, the excellent photocatalytic activity of the urchin-like hierarchical TiO2 was confirmed by photodegradation of methyl blue in water. 相似文献
6.
Wenwen Wang Dongjiang Yang Weiyou Yang Jin Sun Huilin Hou 《Journal of Materials Science: Materials in Electronics》2017,28(2):1271-1280
The wide application of the titanium dioxide (TiO2) as the photocatalysts is greatly hindered by its intrinsic large band gap and usually fast electron–hole recombination. Here, we reported the exploration of coupling g-C3N4 nanoflakes to TiO2 nanotubes with the anatase and TiO2(B) mixed phases (TiO2(AB)) toward the efficient visible-light-driven hybrid photocatalyst. It is found that coupling TiO2(AB) nanotubes with g-C3N4 nanoflakes could bring a profoundly extension the visible light adsorption capacity and enhanced photogenerated carrier separation. Accordingly, they exhibit much higher efficient photocatalytic activities toward the degradation of sulforhodamine B under the visible light irradiation, which is enhanced for nearly 15 times to those of the TiO2(AB) and g-C3N4, suggesting their promising practical applications as novel and efficient semiconductor photocatalysts for the water purification. 相似文献
7.
Sanjay B. Kokane R. Sasikala D. M. Phase S. D. Sartale 《Journal of Materials Science》2017,52(12):7077-7090
Fast recombination of photogenerated charge carriers is a major problem in the photoelectrochemical and photocatalytic processes. In this work, we report significantly improved PEC performance of a nanocomposite consists of In2S3 nanoparticles dispersed on g-C3N4 nanosheets synthesized by a simple and facile wet chemical route. The results of high-resolution TEM study show that the obtained In2S3 nanoparticles of size 10–20 nm exist in cubic phase and are uniformly dispersed on the surface of g-C3N4 nanosheets. The In2S3/g-C3N4 nanocomposite with 25 weight percentage of In2S3 exhibits 8.5 times higher photocurrent density than the single-phase g-C3N4 under visible light illumination. The enhanced photocurrent density exhibited by the In2S3/g-C3N4 nanocomposite is attributed to the efficient separation of photogenerated charge carriers. The charge transfer mechanism in In2S3/g-C3N4 heterojunction was studied by a series of experiments, such as electrochemical impedance spectroscopy, photoelectrochemical measurement and photoluminescence emission spectroscopy. The intimate interface promotes the charge transfer and inhibits the recombination rate of photogenerated electron–hole pairs, which significantly improves the photoelectrochemical performance. A detailed charge transfer mechanism is discussed based on the Mott–Schottky plot study. This heterojunction material is found to be an efficient photocatalyst for the degradation of both cationic rhodamine B dye and anionic methyl orange dye as the lifetime of photogenerated charge carriers is higher in the composite than in single-phase In2S3 and g-C3N4. A strong correlation between the photoelectrochemical and the photocatalytic performances is observed in this composite. 相似文献
8.
Haijin Liu Cuiwei Du Haokun Bai Yuzhao Su Dandan Wei Yuqian Wang Guoguang Liu Lin Yang 《Journal of Materials Science》2018,53(15):10743-10757
A class of direct plate-on-plate Z-scheme heterojunction SnS2/Bi2MoO6 photocatalysts was synthesized via a two-step hydrothermal method. The materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, Fourier transform infrared photoluminescence emission spectra, and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity was estimated via the degradation of crystal violet (CV) and ciprofloxacin (CIP). The experimental results indicated that the 5 wt% SnS2/Bi2MoO6 composites exhibited significantly enhanced performance in contrast to pure Bi2MoO6 or SnS2 nanoflakes, and were also superior to the popular TiO2 (P25). The degradation reaction accorded well with the first-order reaction kinetics equation; the rate constant of CV using a SnS2 content of 5 wt% photocatalyst was ~?3.6 times that of the Bi2MoO6 and 2.4 times that of SnS2. Furthermore, a SnS2 content of 5 wt% exhibited a 1.7 times higher photocatalytic activity of CIP than that of pure Bi2MoO6, and 1.3 times that of pure SnS2. Radical trapping experiments and an electron spin resonance technique indicated that h+ and ·OH were the dominant active species involved in the degradation process. A plasmonic Z-scheme photocatalytic mechanism was proposed to explain the superior photocatalytic activities and efficient separation of photogenerated electrons and holes. 相似文献
9.
Yu. F. Kargin S. N. Ivicheva A. S. Lysenkov N. A. Ovsyannikov L. I. Shvorneva K. A. Solntsev 《Inorganic Materials》2012,48(9):897-902
Si3N4/TiN composites have been produced by hot pressing at temperatures from 1600 to 1800°C in a nitrogen atmosphere, using silicon nitride powders prepared by self-propagating high-temperature synthesis and surface-modified with titanium dioxide nanoparticles. We examined the effect of TiO2 content on the microstructure, phase composition, and mechanical strength of the ceramics. It is shown that titanium nitride can be formed by the reaction Si3N4 + TiO2 → TiN + NO + N2O + 3Si. The Si3N4/TiN composites containing 5–20% TiN have a low density, high porosity, and a bending strength of 60 MPa or lower. In Si3N4/TiN ceramics produced using calcium aluminates as sintering aids, the silicon nitride grains are densely packed, which ensures an increase in strength to 650 MPa. 相似文献
10.
Shanmugam Vignesh Anna Lakshmi Muppudathi Jeyaperumal Kalyana Sundar 《Journal of Materials Science: Materials in Electronics》2018,29(13):10784-10801
Highly active gC3N4-BiFeO3-Cu2O nanocomposites were successfully prepared via a facile, cost effective and eco-friendly method of hydrothermally wet precipitation combined with ultrasonic dispersion process. The prepared samples were characterized by XRD, FTIR, HRSEM, EDS, TEM, UV–Vis DRS, PL, VSM, BET and electrochemical properties. By means of these analysis for examine the crystal phase, nanostructure, band gap and light-harvesting properties were carried out. UV-DRS spectra indicate that the bandgap of g-C3N4 (2.7 eV) reduced to 2.59 and 2.21 eV by mixed with corresponds to BiFeO3 and BiFeO3/Cu2O nanomaterials. The ideal photocatalytic activity of the gC3N4-BiFeO3-Cu2O nanocomposites, where RhB dye under visible light irradiation which was up to 4.36 and 2.52 times as the higher photodegradation ability to compare pristine g-C3N4 and gC3N4-BiFeO3 catalyst. The magnetization was confirmed by VSM studies, and hence, after the photocatalytic reaction, the magnetically separable catalyst can be quickly separated from the water by an external magnetic field. The superior photocatalytic performance is due to the synergistic effect on the interface of BiFeO3/Cu2O in the gC3N4-BiFeO3-Cu2O nanocomposites has reduced the bandgap which enables high separation efficiency of the charge carrier, suppressed recombination rate and their high surface area. Moreover, the chief gC3N4-BiFeO3-Cu2O catalyst can exhibited the lesser charge transfer resistance (impedance), enhances of photocurrent responses, whereas exposed to the development of photocatalytic appearance and more charge carrier ability. Also, the antibacterial activity of the gC3N4-BiFeO3-Cu2O nanocomposite has showing a well deactivation in both G+ (S. aureus) and G? (E. coli) bacteria’s whereas compare to other prepared samples. 相似文献
11.
One-dimension carbon self-doping g-C3N4 nanotubes (CNT) with abundant communicating pores were synthesized via thermal polymerization of saturated or supersaturated urea inside the framework of a melamine sponge for the first time. A ~16% improvement in photoelectric conversion efficiency (η) is observed for the devices fabricated with a binary hybrid composite of the obtained CNT and TiO2 compared to pure TiO2 device. The result of EIS analysis reveals that the interfacial resistance of the TiO2-dye|I3?/I? electrolyte interface of TiO2-CNT composite cell is much lower than that of pure TiO2 cell. In addition, the TiO2-CNT composite cell exhibits longer electron recombination time, shorter electron transport time, and higher charge collection efficiency than those of pure TiO2 cell. Systematic investigations reveal that the CNT boosts the light harvesting ability of the photovoltaic devices by enhancing not only the visible light absorption but also the charge separation and transfer. 相似文献
12.
Wee-Jun Ong Lutfi Kurnianditia Putri Yoong-Chuen Tan Lling-Lling Tan Neng Li Yun Hau Ng Xiaoming Wen Siang-Piao Chai 《Nano Research》2017,10(5):1673-1696
In this work,we demonstrated the successful construction of metal-free zerodimensional/two-dimensional carbon nanodot (CND)-hybridized protonated g-C3N4 (pCN) (CND/pCN) heterojunction photocatalysts by means of electrostatic attraction.We experimentally found that CNDs with an average diameter of 4.4 nm were uniformly distributed on the surface of pCN using electron microscopy analysis.The CND/pCN-3 sample with a CND content of 3 wt.% showed the highest catalytic activity in the CO2 photoreduction process under visible and simulated solar light.Thisprocess results in the evolution of CH4 and CO.The total amounts of CH4 and CO generated by the CND/pCN-3 photocatalyst after 10 h of visible-light activity were found to be 29.23 and 58.82 μmol·gcatalyst-1,respectively.These values were 3.6 and 2.28 times higher,respectively,than the amounts generated when using pCN alone.The corresponding apparent quantum efficiency (AQE) was calculated to be 0.076%.Furthermore,the CND/pCN-3 sample demonstrated high stability and durability after four consecutive photoreaction cycles,with no significant decrease in the catalytic activity.The significant improvement in the photoactivity using CND/pCN-3 was attributed to the synergistic interaction between pCN and CNDs.This synergy allows the effective migration of photoexcited electrons from pCN to CNDs via wellcontacted heterojunction interfaces,which retards the charge recombination.This was confirmed by photoelectrochemical measurements,and steady-state and time-resolved photoluminescence analyses.The first-principles density functional theory (DFT) calculations were consistent with our experimental results,and showed that the work function of CNDs (5.56 eV) was larger than that of pCN (4.66 eV).This suggests that the efficient shuttling of electrons from the conduction band of pCN to CNDs hampers the recombination of electron-hole pairs.This significantly increased the probability of free charge carriers reducing CO2 to CH4 and CO.Overall,this study underlines the importance of understanding the charge carrier dynamics of the CND/pCN hybrid nanocomposites,in order to enhance solar energy conversion. 相似文献
13.
Yu. F. Kargin S. N. Ivicheva N. A. Ovsyannikov A. S. Lysenkov A. S. Chernyavsky N. A. Alad’ev S. V. Kutsev 《Inorganic Materials》2009,45(5):511-516
Silicon nitride nanofilaments were synthesized at 1600°C in nitrogen on the surface of a ceramic substrate made of amorphous silicon oxynitride obtained by hexamethyl disilasane pyrolysis. The diameter of filaments represented by different morphological types (filaments, ribbons, needles) was 100–500 nm, and the length was several millimeters. 相似文献
14.
Zhihuan Zhao Xiao Zhang Jimin Fan Dongfeng Xue Bing Zhang Shu Yin 《Journal of Materials Science》2018,53(10):7266-7278
The ternary composites consisted of nitrogen-doped titanium dioxide, carbon nitride and up-conversion phosphors (UP) were successfully prepared by a solvothermal method. The heterojunction could be formed when N-TiO2 and g-C3N4 were combined together. The composite of N-TiO2/g-C3N4@UP had excellent ultraviolet, visible and infrared light absorption, indicating the possibility for the utilization of full spectrum of solar light. When N-TiO2 was coupled with g-C3N4 and up-conversion phosphors to form a composite, the visible light and NIR light absorption of the samples increased. The ternary composite N-TiO2/g-C3N4@G-UP presented reasonable deNO x performance of about 8.0% under the irradiation of IR light of 980 nm. The intensification of the photocatalysis might be realized by utilizing up-conversion phosphors, which could convert low-energy NIR light into high-energy photons (visible light) and increase the efficient irradiation on the surface of photocatalyst. 相似文献
15.
A novel Ag3PO4-AgBr-PTh composite loaded on Na2SiO3 was synthesized for enhanced visible-light photocatalytic activity. The photocatalytic activity of the samples was evaluated by photodegrading rhodamine B (RhB) under visible light irradiation. The main reactive species and possible photocatalytic mechanism were also discussed. As a result, the Ag3PO4-AgBr-PTh composite loaded on Na2SiO3 exhibited enhanced photocatalytic activity for RhB compared with Ag3PO4 under visible-light irradiation. Additionally, it was demonstrated that the hole (h+) and superoxide radical (?O 2 ? ) were the major reactive species involving in the RhB degradation. PTh played vital role for the enhanced photocatalytic activity of Ag3PO4-AgBr-PTh-Na2SiO3 composite, which offered an electron transfer expressway and accelerated the transfer of the electrons from the CB of AgBr into Ag3PO4. This work could provide a new perspective for the synthesis of Ag3PO4-based composites and the improvement of photocatalytic activity of Ag3PO4. 相似文献
16.
Yanwu Chen Teng Yuan Feng Wang Jianqing Hu Weiping Tu 《Journal of Materials Science: Materials in Electronics》2016,27(10):9983-9988
A facile and efficient approach for the fabrication of Fe3O4@TiO2 nanospheres with a good core–shell structure has been demonstrated. Products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The results showed that Fe3O4@TiO2 nanocomposites exhibited high degree of crystallinity, excellent magnetic properties at room temperature. Furthermore, the as-prepared Fe3O4@TiO2 nanocomposites exhibited good photocatalytic activity toward the degradation of Rhodamine B (RhB) solution. Additionally, the recycling experiment of Fe3O4@TiO2 nanocomposites had been done, demonstrating that Fe3O4@TiO2 nanocomposites have high efficiency and stability. 相似文献
17.
Rajat Kanti Paul Chi-Woo Lee Hai-Doo Kim Byong-Taek Lee 《Journal of Materials Science》2007,42(12):4701-4706
Porous Si3N4–Si2N2O bodies fabricated by multi-pass extrusion process were investigated depending on the feldspar addition content (4–8 wt% Si)
in the raw silicon powder. The diameter of the continuous pores was about 250 μm. The polycrystalline Si2N2O fibers observed in the continuous pores as well as in the matrix regions of the nitrided bodies can increase the filtration
efficiency. In the 4 wt% feldspar addition, the diameter of the Si2N2O fibers in the continuous pores of the nitrided bodies was about 90–150 nm. A few number of rope typed Si2N2O fibers (∼4 μm) was found in the case of 8 wt% feldspar addition. However, in the 8 wt% feldspar addition, the matrix showed
highly porous structure composed of large number of the Si2N2O fibers (∼60 nm). The relative densities of the Si3N4–Si2N2O bodies with 4 wt% and 8 wt% feldspar additions were about 65% and 61%, respectively. 相似文献
18.
O. F. Pozdnyakov L. N. Blinov Mohammad Arif A. O. Pozdnyakov S. N. Filippov A. V. Semencha 《Technical Physics Letters》2005,31(12):1001-1003
Carbon nitride has been synthesized in macroscopic amounts by means of the original method based on an ecologically safe technology using inorganic initial compounds. The product has been characterized by mass spectrometry (MS), X-ray diffraction, and quantitative chemical analysis. The MS and thermochemical data show that stoichiometry of the samples of carbon nitride obtained using the proposed method corresponds to the empirical formula C3N4. 相似文献
19.
A series of Bi2S3/(BiO)2CO3 composite photocatalysts with different loadings of amorphous Bi2S3 were successfully synthesized through an ultrasonic-assisted ion-exchange reaction between thioacetamide (CH3CSNH2) and (BiO)2CO3, and characterized by XRD, XPS, BET, EELS, EDX, SEM, TEM/HRTEM, UV–Vis, and photoluminescence (PL) techniques. The results of TEM/HRTEM, EELS, and EDX indicate that the composite catalyst Bi2S3/(BiO)2CO3 has been successfully synthesized with the deposited Bi2S3 present in amorphous state on the surface of (BiO)2CO3. The activities of the catalysts for RhB degradation under visible light show that the catalyst prepared under ultrasonic is more active than the one synthesized without ultrasonic. The optimized sample Bi2S3/(BiO)2CO3 (U5.0) exhibits a much higher activity, about 4.8 times to that of pure (BiO)2CO3. Based upon the band structures of Bi2S3/(BiO)2CO3, it is deduced that the migration of the visible light-induced electrons from the conduction band of Bi2S3 to that of (BiO)2CO3 should have facilitated the separation of photogenerated carriers, as confirmed by the suppressed photoluminescence spectra. Using different scavengers, the ·O2 ? and holes are clearly identified as the main oxidative species for RhB photodegradation. In light of these observations, a potential photocatalytic mechanism of RhB degradation over Bi2S3/(BiO)2CO3 is proposed. 相似文献
20.
Qishe Yan Xin Xie Cuiping Lin Yalei Zhao Shenbo Wang Yonggang Liu 《Journal of Materials Science: Materials in Electronics》2017,28(22):16696-16703
The nano-scale Ag3PO4 was successfully synthesized by the silver ammonia complexing precipitation method at room temperature. And the Graphene oxide (GO)/Ag3PO4 nanocomposites with different contents of GO were successfully synthesized using the electrostatic driving method. The as-prepared GO/Ag3PO4 nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–visible diffuse reflectance spectroscopy (UV–Vis DRS), confirming that Ag3PO4 were highly dispersed to GO sheet. The photocatalytic properties of GO/Ag3PO4 were evaluated by the degradation of Methyl Orange (MO) under visible light irradiation and solar irradiation respectively. The results showed that the photocatalytic efficiencies of GO/Ag3PO4 nanocomposites had enhanced largely and the kinetics reaction models were followed first-order. Furthermore, 5% GO/Ag3PO4 exhibited the highest photocatalytic activity on degradation of MO under visible-light irradiation. The improved photocatalytic performances of the GO/Ag3PO4 nanocomposites mainly attributed to the introducing of GO, which benefit for electron transfer and inhibit the recombination of electron–hole pairs, promoting the practical application of Ag3PO4 in water purification. 相似文献