Metal ion and N co-doped TiO2 as a visible-light photocatalyst

2004 ◽  
Vol 19 (7) ◽  
pp. 2100-2108 ◽  
Author(s):  
Yoshiaki Sakatani ◽  
Hiroyuki Ando ◽  
Kensen Okusako ◽  
Hironobu Koike ◽  
Jun Nunoshige ◽  
...  

Powders of TiO2 doped with a metal ion and N species were prepared by a polymerized complex method and the visible-light photocatalytic activities of the products are investigated. Of the metal ions studied (K+, Ca2+, Sr2+, Ba2+, Nb5+, Fe3+, Zn2+, and Al3+), the photocatalyst prepared with Sr2+ exhibits the highest activity for acetaldehyde decomposition under visible-light irradiation. Results obtained from x-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) analyses suggest that the doped N species reside at interstitial lattice positions in the catalyst. It was also found by XPS and ESR measurements that the doped N species combine with lattice oxygen to give rise to a paramagnetic property. The visible-light response of the catalyst is driven by the formation of paramagnetic N species at interstitial positions in the TiO2 lattice.

2018 ◽  
Vol 78 (8) ◽  
pp. 1802-1811 ◽  
Author(s):  
Jiwei Huang ◽  
Changlong Yang ◽  
Qiang Song ◽  
Dongxue Liu ◽  
Li Li

Abstract A series of different ratios of Ag2S/ZnO/ZnS nanocomposites with visible light response were prepared by a microwave-assisted hydrothermal two-step method, whose composition, crystalline structure, morphology and surface physicochemical properties were well-characterized via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis/DRS), photoluminescence spectrum (PL), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and N2 adsorption–desorption measurements. Results showed that as-composites mainly consisted of ZnS crystal phase, whose grain size increased obviously compared with non Ag2S samples. At the same time, due to the introduction of narrow band gap Ag2S, the synthesized composite can effectively increase the visible optical absorption of ZnO/ZnS composites. Among them, 1% Ag2S/ZnO/ZnS showed a mixed structure of nano-line and nano-particle, of which BET value increased significantly, and the morphology was more excellent. Photocatalytic activities of a series of Ag2S/ZnO/ZnS composites under different light sources were studied using methyl orange as a model molecule, and 1% Ag2S/ZnO/ZnS was taken as the best one. Meanwhile, 1% Ag2S/ZnO/ZnS also showed a good degradation effect on other dyes with different structures, and its degradation efficiency did not change significantly after three cycles, showing certain stability. In addition, composites with Ag2S loading of 1% possessed the highest hydrogen production ability of photolysis water, indicating that the introduction of Ag2S had significantly enhanced the catalytic performance.


2012 ◽  
Vol 486 ◽  
pp. 368-372
Author(s):  
Hui Zhao ◽  
Yan Wang

In this paper, nanotubular TiO2 obtained by hydrothermal method was selected as precursor to prepare metal ion decorated TiO2-xNxvia a facile and one-pot method. As-synthesized M/TiO2-xNx (M references to Pd, Fe, Ni, Li) photocatalysts were characterized by means of X-ray diffraction, diffuse reflectance spectrometry, fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic activities of different metal ion decorated TiO2-xNx samples were compared by monitoring the photocatalytic oxidation of propylene under both ultraviolet light (UV) and visible light (Vis) irradiation. It was found that Pd/TiO2-xNx sample possessed the highest photocatalytic activity under both UV and Vis irradiation. The better crystallinity, better visible light absorption, higher hydroxy concentration were contributed to the best photocatalytic performance of Pd/TiO2-xNx.


NANO ◽  
2016 ◽  
Vol 11 (03) ◽  
pp. 1650035 ◽  
Author(s):  
Lin Ma ◽  
Limei Xu ◽  
Xuyao Xu ◽  
Xiaoping Zhou ◽  
Lingling Zhang

Sulfur-doped SnO2 nanoparticles with ultrafine sizes have been successfully prepared by a one-pot hydrothermal method. The obtained samples are characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), thermogravimetric (TG), analyzer UV-Vis spectroscopy, photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the doping level of sulfur element as well as the bandgaps of SnO2 can be controlled to a certain extent by varying the amount of L-cysteine (L-cys). When evaluated as photocatalysts in the degradation of rhodamine B (RhB) and reduction of Cr(VI) under visible light region, the resultant sulfur-doped SnO2 nanoparticles demonstrate obviously enhanced photocatalytic activities due to the markedly improved visible light response and effective separation of the photo-generated electron–hole pairs.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Yingying Li ◽  
Xianliang Song ◽  
Zhedong Wei ◽  
Jianguang Zhang ◽  
Lijuan Qin ◽  
...  

Mo-titaniumdioxide (P25) photocatalyst with visible-light response was prepared with the ammonium molybdate for Mo source and titaniumdioxide for the raw materials by the method of dissolving and calcining. The photocatalysts’ structure was characterized by XRD, XPS, and UV-Vis absorption spectrum and TEM. The photocatalytic activities of Mo-titaniumdioxide were measured by the degradation of methylene blue (MB) under visible-light irradiation. The results showed that Mo characteristic peaks appeared at the point of 235.45 eV, 234.2 eV, 232.3 eV, and 231.1 eV. In Mo-titaniumdioxide crystal lattice, Mo6+had the highest percentage (about 84.08%), indicating that Mo element was inserted into titaniumdioxide crystal lattice and considerable amount of Mo dopant was in the 6+ valence state, which restrained the recombination of electron-hole and had the visible-light photocatalytic activity. Photocatalytic degradation study indicated that the samples prepared at calcination temperature of 500°C were used to degrade MB; after 3 h, the degradation reached up to 80.67%.


2022 ◽  
pp. 152808372110569
Author(s):  
Jing Han ◽  
Hai-Tao Ren ◽  
Ting-Ting Li ◽  
Bing-Chiuan Shiu ◽  
Yong-Gui Li ◽  
...  

Visible light response PAN@Ag-Ag2O/Sch (PAN@AS, schwertmannite and polyacrylonitrile abbreviated as Sch and PAN) nanofibers with different mass ratios were synthesized by electrospinning technology and pH-induced precipitation reaction. X-Ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy analysis showed that the formation of Ag-Ag2O/Sch heterojunction and Ag-Ag2O nanoparticles were evenly distributed on the surface of Sch. The prepared nanofibers have high oxidative removal performance for As(III) under visible light. In the [email protected] system, the total As removal percent can reach 90.96% after 120 min irradiation at pH 4.0. The scavenger experiments confirmed that the main active substances of the [email protected] system were h+ and •OH. The high oxidation and removal performance of the [email protected] composite for As(III) was attributed to the effective separation of photogenerated electron-hole pairs and high adsorption capacity of Sch for As under acidic conditions. This research provides a new material for the oxidation and removal of pollutants in water [such as As(III)] and also provides a research basis for the preparation of recyclable photocatalysts.


2012 ◽  
Vol 550-553 ◽  
pp. 404-410
Author(s):  
Hua Jun Chen ◽  
Xiao Jing Xi ◽  
Dong Li ◽  
Rui Wang

A Bi-TiO2 composite with high photocatalytic activity was prepared using tetrabutyl titanate and bismuth nitrate as raw material by hydrothermal method. The structure was characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), X-ray energy dispersive spectroscopy(EDS), X-ray fluorescence(XRF) and UV-vis diffuse reflectance spectrophotometer(UV-vis DRS). The results show that anatase nanometer titanium dioxide was prepared, in which Bi3+ take the place of Ti4+. The surface area of the sample was higher, ca.312.6m2•g-1. Bi doping caused red-shift of the absorption spectrum, and the composite has better Visible-light Response. Bi-TiO2 shows higher photocatalytic avtivity to the degradation of resorcinol than pure TiO2. The optimum value of Bi doped was 1.00 %. After 120 minutes illuminating under 70W Halide Lamps, degradation rate of resorcinol can get to 100%.


2018 ◽  
Vol 7 (4.5) ◽  
pp. 105 ◽  
Author(s):  
Harsha Bantawal ◽  
D Krishna Bhat

Hierarchical porous BaTiO3 nano-hexagons was synthesized via a simple hydrothermal route by using TiO2 and Ba(OH)2.8H2O as starting materials under alkaline environment and its photocatalytic activity was evaluated under visible light by taking methylene blue (MB) as a model pollutant. The prepared BaTiO3 was characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), energy dispersive X-rays analysis (EDX), high resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET) analysis and diffused reflectance spectroscopy (DRS) techniques. It is noteworthy that the BaTiO3 nano-hexagons exhibited significant photocatalytic activity towards the degradation of MB under visible light irradiation. This significant photocatalytic activity of BaTiO3 under visible light is mainly attributed to the special morphology and formation of Ti3+ defects.  


2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Workneh M. Shume ◽  
H. C. Ananda Murthy ◽  
Enyew Amare Zereffa

Even though the photocatalytic processes are a good technology for treatment of toxic organic pollutants, the majority of current photocatalysts cannot utilize sunlight sufficiently to realize the decomposition of these organic pollutants. As stated by various researchers, metal oxide nanoparticles have a significant photocatalytic performance under visible light source. Among various chemical and physical methods used to synthesize nanostructured silver oxide, green synthetic route is a cheaper and environmental friendly method. To confirm the optimum production of Ag2O NPs, effect of pH, extract concentration, metal ion concentration, and contact time were optimized. The structure, morphology, crystallinity, size, purity, elemental composition, and optical properties of obtained Ag2O NPs were characterized by different techniques, such as scanning electron microscopy (SEM), transmission electron microscope (HRTEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and UV-visible spectrophotometer accordingly as revealed by our literature review. The photocatalytic performance of the synthesized nanocrystalline Ag2O by photocatalytic degradation of organic dyes under visible light irradiation has been discussed thoroughly in this review. Many past studies revealed that organic dyes and pollutants are decomposed completely by green synthesized Ag2O NPs under irradiation of visible light.


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