In Situ Synthesis of Ti3+ Self-Doped TiO2/N-Doped Carbon Nanocomposites and its Visible Light Photocatalytic Performance

NANO ◽  
2016 ◽  
Vol 11 (08) ◽  
pp. 1650088 ◽  
Author(s):  
Chaoyi Wu ◽  
Zhenggang Gao ◽  
Shanmin Gao ◽  
Qingyao Wang ◽  
Zeyan Wang ◽  
...  

Ti[Formula: see text] self-doped TiO2 (TiO[Formula: see text])/N-doped carbon nanostructure composites were prepared via a facile one-step hydrothermal method to optimize the use of visible light and reduce recombination of photogenerated electrons and holes. The composites were characterized by X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The amounts of carbon and nitrogen sources affect the morphology and photocatalytic performance. At low amounts of the sources, the N-doped carbon nanostructure is an amorphous film and is well-combined with TiO[Formula: see text] nanoparticles through surface carbon–oxygen groups. At high amounts of the sources, N-doped carbon quantum dots (NCQDs) were obtained, and carbon atoms could substitute for oxygen atoms in the TiO2 lattice to form Ti–C structures, which are responsible for the high photocatalytic activity under visible light illumination. Transient photocurrent response and electrochemical impedance spectroscopy results indicate that the amorphous hybrid film becomes a trap for electrons and that NCQDs can accelerate electron transfer. The improved visible light photocatalytic property for the TiO[Formula: see text]/NCQDs composite can be attributed to the enhancement of light absorption and inhibition of the photogenerated electron–hole recombination of anchored NCQDs.

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1054 ◽  
Author(s):  
Yanzhong Zhen ◽  
Jie Wang ◽  
Feng Fu ◽  
Wenhao Fu ◽  
Yucang Liang

The novel ternary-component Ag/AgI/α-MoO3 (AAM) photocatalyst was successfully fabricated by a facile hydrothermal method combined with a charge-induced physical adsorption and photo-reduced deposition technique. X-ray diffraction, scanning/transmission electron microscope, X-ray photoelectron, UV-vis diffuse reflectance, photoluminescence and electrochemical impedance spectroscopy were employed to characterize the composition, morphology, light-harvesting properties and charge transfer character of the as-synthesized catalysts. The ternary-component AAM heterojunctions exhibited an excellent visible-light photocatalytic oxidative desulfurization activity, in which the AAM-35 (35 represents weight percent of AgI in AAM sample) possessed the highest photocatalytic activity of the conversion of 97.5% in 2 h. On the basis of band structure analysis, radical trapping experiments and electron spin resonance (ESR) spectra results, two different catalytic mechanisms were suggested to elucidate how the photogenerated electron-hole pairs can be effectively separated for the enhancement of photocatalytic performance for dual composites AM-35 and ternary composites AAM-35 during the photocatalytic oxidative desulfurization (PODS) of thiophene. This investigation demonstrates that Z-scheme Ag/AgI/α-MoO3 will be a promising candidate material for refractory sulfur aromatic pollutant’s removal in fossil fuel.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Min Fu ◽  
Jiazhen Liao ◽  
Fan Dong ◽  
Hongmei Li ◽  
Hongyan Liu

Novel visible light photocatalytic graphitic carbon nitride/TiO2(g-C3N4/TiO2) composite samples were synthesized by heating mixtures of melamine and commercial TiO2(TO) at different weight ratios. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), Fourier transform infrared spectroscopy (FTIR), and UV-visible diffused reflectance spectroscopy (UV-vis DRS). Characterization confirms formation of nanocomposites of g-C3N4/TiO2. At the optimized precursor weight ratio (melamine:mTiO2=2.5), the samples exhibited highest adsorption capacity and visible light photocatalytic activity, measured by degradation of methylene blue (MB). Under visible light irradiation, the excited electrons on the surface of g-C3N4transfer easily to the conduction band (CB) of TiO2via the well-built heterojunction. The g-C3N4/TiO2nanocomposites exhibit enhanced visible light catalytic activity due to increased visible light adsorption and effective separation of photogenerated electron-hole pairs. These g-C3N4/TiO2nanocomposites could find broad applicability in environmental protection due to their excellent visible light photocatalytic property and facile, cost-effective preparation process.


2020 ◽  
Vol 10 (9) ◽  
pp. 3238
Author(s):  
Min Liu ◽  
Guangxin Wang ◽  
Panpan Xu ◽  
Yanfeng Zhu ◽  
Wuhui Li

In this study, the Ag3PO4/SnO2 heterojunction on carbon cloth (Ag3PO4/SnO2/CC) was successfully fabricated via a facile two-step process. The results showed that the Ag3PO4/SnO2/CC heterojunction exhibited a remarkable photocatalytic performance for the degradation of Rhodamine B (RhB) and methylene blue (MB), under visible light irradiation. The calculated k values for the degradation of RhB and MB over Ag3PO4/SnO2/CC are 0.04716 min−1 and 0.04916 min−1, which are higher than those calculated for the reactions over Ag3PO4/SnO2, Ag3PO4/CC and SnO2/CC, respectively. The enhanced photocatalytic activity could mainly be attributed to the improved separation efficiency of photogenerated electron-hole pairs, after the formation of the Ag3PO4/SnO2/CC heterojunction. Moreover, carbon cloth with a large specific surface area and excellent conductivity was used as the substrate, which helped to increase the contact area of dye solution with photocatalysts and the rapid transfer of photogenerated electrons. Notably, when compared with the powder catalyst, the catalysts supported on carbon cloth are easier to quickly recycle from the pollutant solution, thereby reducing the probability of recontamination.


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3948
Author(s):  
Lingfang Qiu ◽  
Zhiwei Zhou ◽  
Mengfan Ma ◽  
Ping Li ◽  
Jinyong Lu ◽  
...  

Novel visible-light responded aluminosilicophosphate-5 (SAPO-5)/g-C3N4 composite has been easily constructed by thermal polymerization for the mixture of SAPO-5, NH4Cl, and dicyandiamide. The photocatalytic activity of SAPO-5/g-C3N4 is evaluated by degrading RhB (30 mg/L) under visible light illumination (λ > 420 nm). The effects of SAPO-5 incorporation proportion and initial RhB concentration on the photocatalytic performance have been discussed in detail. The optimized SAPO-5/g-C3N4 composite shows promising degradation efficiency which is 40.6% higher than that of pure g-C3N4. The degradation rate improves from 0.007 min−1 to 0.022 min−1, which is a comparable photocatalytic performance compared with other g-C3N4-based heterojunctions for dye degradation. The migration of photo-induced electrons from g-C3N4 to the Al site of SAPO-5 should promote the photo-induced electron-hole pairs separation rate of g-C3N4 efficiently. Furthermore, the redox reactions for RhB degradation occur on the photo-induced holes in the g-C3N4 and Al sites in SAPO-5, respectively. This achievement not only improves the photocatalytic activity of g-C3N4 efficiently, but also broadens the application of SAPOs in the photocatalytic field.


Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 437 ◽  
Author(s):  
Zhiming Sun ◽  
Fang Yuan ◽  
Xue Li ◽  
Chunquan Li ◽  
Jie Xu ◽  
...  

A novel kind of cyanuric-acid-modified graphitic carbon nitride (g-C3N4)/kaolinite (m-CN/KA) composite with enhanced visible light-driven photocatalytic performance was fabricated through a facile two-step process. Rhodamine B (RhB) was taken as the target pollutant to study the photocatalytic performance of the synthesized catalysts. It is indicated that the cyanuric acid modification significantly enhanced photocatalytic activity under visible light illumination in comparison with the other reference samples. The apparent rate constant of m-CN/KA is almost 1.9 times and 4.0 times those of g-C3N4/kaolinite and bare g-C3N4, respectively. The superior photocatalytic performance of m-CN/KA could be ascribed, not only to the generation of abundant pore structure and reactive sites, but also to the efficient separation of the photogenerated electron-hole pairs. Furthermore, the possible photocatalytic degradation mechanism of m-CN/KA was also presented in this paper. It could be anticipated that this novel and efficient, metal-free, mineral-based photocatalytic composite has great application prospects in organic pollutant degradation.


RSC Advances ◽  
2014 ◽  
Vol 4 (57) ◽  
pp. 30090-30099 ◽  
Author(s):  
Wenshu Tang ◽  
Yu Su ◽  
Xiaoxin Wang ◽  
Qi Li ◽  
Shian Gao ◽  
...  

A novel superparamagnetic Ag@silver-based salt photocatalyst was created with highly efficient visible light photocatalytic performance and easy magnetic separation.


2021 ◽  
Author(s):  
Rui Zhang ◽  
ziyin chen ◽  
Chen Zhao ◽  
Kunlin Zeng ◽  
Lu Cai ◽  
...  

Abstract A novel binary BiSI/Ag2CO3 photocatalyst with excellent visible light-driven photocatalytic performance was prepared. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the samples were evaluated by photocatalytic degradation of rhodamine B(RhB) under the irradiation of visible light. The results showed that the BiSI improves the photocatalytic activity of BiSI/Ag2CO3. Moreover, when the mass ratio of BiSI in BiSI/Ag2CO3 composites was 40%, the as-prepared BiSI/Ag2CO3 composite exhibited the best photocatalytic activity for degrading RhB. Finally, the possible mechanism for photodegradation over the BiSI/Ag2CO3 composites is also proposed.


2018 ◽  
Vol 8 (17) ◽  
pp. 4399-4406 ◽  
Author(s):  
Qi Liu ◽  
Fengjiao Wang ◽  
Huaxiang Lin ◽  
Yanyu Xie ◽  
Na Tong ◽  
...  

Compared to the pristine WO3, the oxygen vacancy defect levels of the sub-stoichiometric WO3−X narrow the bandgap and promote the separation of photogenerated electron–hole pairs.


2011 ◽  
Vol 306-307 ◽  
pp. 1459-1463
Author(s):  
Yan Jun Xin ◽  
De Jie Cui

Wormhole-shaped F-doped TiO2/Ti photoelectrodes were prepared by microarc oxidation method in NaF solution. The morphology and structure of the photoelectrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF). It was found that F-doped TiO2/Ti photoelectrodes were porous and composed of anatase TiO2. The photocatalytic properties of F-doped TiO2/Ti photoelectrodes were investigated by photodiscoloration rate of Rhodamine B(Rh.B) under different conditions. All results showed that the photoelectrodes prepared at voltage of 160V, NaF concentration of 0.01mol/L and oxidation time of 10min have optimal photocatalytic performance. Rh.B was almost completely removed by F-doped TiO2/Ti photoelectrodes after 120min under the illumination of artificial visible light.


RSC Advances ◽  
2017 ◽  
Vol 7 (63) ◽  
pp. 40028-40033 ◽  
Author(s):  
Hao Xu ◽  
Zhixing Gan ◽  
Weiping Zhou ◽  
Zuoming Ding ◽  
Xiaowei Zhang

Insufficient visible light absorption and fast recombination of the photogenerated electron–hole pairs have seriously hampered the photocatalytic performance of graphitic carbon nitride (g-C3N4) up to now.


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