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1.
CuS-graphene oxide/TiO2 composites were prepared using a sol-gel method to improve the photocatalytic performance of the photocatalyst. The composites were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and transmission electron microscopy. The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible-light irradiation. The photodegradation of MB under visible-light irradiation reached 90.1% after 120 min. The kinetics of MB degradation was plotted alongside the values calculated from the Langmuir-Hinshelwood equation. The CuS-graphene oxide/TiO2 sample prepared using 0.2 mol of TiO2 showed the best photocatalytic activity. This was attributed to a cooperative reaction as a result of increased photoabsorption by graphene oxide and an increased photocatalytic effect by CuS.  相似文献   

2.
R.M.MOHAMED  E.AAZAM 《催化学报》2013,34(6):1267-1273
P‐doped TiO2 (PTIO) thin‐films with different P contents were prepared using a sol‐gel method. The thin‐film samples were characterized using various techniques. The photocatalytic activity was evaluated by decomposing butyl benzyl phthalate under visible‐light irradiation. The results showed that the transformation of anatase to the rutile phase was inhibited and grain growth of TiO2 was prevented by P doping. The results confirm that the doped P atoms existed in two chemical forms, and those incorporated in the TiO2 lattice may play a positive role in photocatalysis. The high photocatalytic activities of the PTIO thin‐films may be the result of extrinsic absorption through the creation of oxygen vacancies, rather than excitation of the intrinsic absorption band of bulk TiO2 . The PTIO can be recycled with little depression of the photocatalytic activity. After six cycles, the photocatalytic activity of the PTIO film was still higher than 98%.  相似文献   

3.
E.S.BAEISSA  R.M.MOHAMED 《催化学报》2013,34(6):1167-1172
Ga2O3‐SiO2 nanoparticles were prepared by a sol‐gel method and Pt was then immobilized on their surface via photo‐assisted deposition (PAD). The produced samples were characterized using X‐ray diffraction (XRD), ultraviolet and visible spectroscopy, photoluminescence emission spectroscopy, and surface area measurements. The catalytic performances of the Ga2O3‐SiO2 and Pt/ Ga2O3‐SiO2 samples were evaluated for the degradation of cyanide using visible light. XRD and EDX results showed that the Pt was well dispersed within the Ga2O3‐SiO2 phase and was detected on the surface of the catalyst, which confirmed the successful loading of Pt ions by the PAD method. BET results revealed that the surface area of Ga2O3‐SiO2 was higher than that of Pt/Ga2O3‐SiO2 . 0.3 wt% Pt/Ga2O3‐SiO2 exhibited the highest photocatalytic activity for degradation of cyanide under visible light. The catalyst could be reused with no loss in activity for the first 10 cycles.  相似文献   

4.
Nano-sized Ni particles on TiO2-SiO2 were synthesized by the two methods of photo-assisted deposition(PAD) and impregnation.H2,which is a promising energy carrier,with a low CO concentration was produced by the photocatalytic reforming of glucose(a model biomass) on the Ni/TiO2-SiO2 catalyst.The supported Ni enhanced the rate of H2 production while it suppressed CO selectivity.The catalysts were characterized by X-ray diffraction,X-ray absorption fine structure,transmission electron microscope,and nitrogen adsorption analysis.Both H2 production and CO selectivity were strongly dependent on the preparation method,and PAD-Ni/TiO2-SiO2 was the better catalyst for H2 production with the lowest CO concentration.  相似文献   

5.
A nanocomposite UV-visible light-responsive multiwalled carbon nanotube (MWCNT)/titanium dioxide(TiO2) nanophotocatalyst was successfully synthesized by a modified sol-gel method using titanium isopropoxide and functionalized MWCNTs as the starting precursors. The photocatalytic activity of the TiO2 and the nanohybrid material was investigated through the photodegradation of Reactive Black 5 dye under ultraviolet light irradiation. X-ray diffraction analysis indicated that anatase phase was obtained for both the pure TiO2 and the MWCNT/TiO2 composite, while Raman spectroscopy confirmed the presence of MWCNTs in the composite. Field emission scanning elec-tron microscopy revealed that TiO2 nanoparticles with an individual diameter of about 10–20 nm were coated on the surface of the MWCNTs. The specific surface areas of the samples were found to be 80 and 181 m2/g for the pure TiO2 and MWCNT/TiO2, respectively. As a result, MWCNT/TiO2 showed better photocatalytic performance than pure TiO2 because the high surface area of MWCNTs enabled them to function as good electron acceptors for the retardation of electron-hole pair recombination.  相似文献   

6.
MENG Zeda  OH Wonchun 《催化学报》2012,(9):1495-1501
CoS2,CoS 2-C60 /TiO2,CoS2-CNT/TiO2,and CoS2-Graphene/TiO2 were prepared.The TiO2 products had the anatase phase structure and interesting surface compositions.X-ray diffraction patterns of the CoS2-carbon/TiO2 composites showed a single and clear anatase phase and the CoS2 structure.Scanning electron microscopy characterization of the texture on the CoS 2-carbon/TiO2 composites showed a homogenous composition.Energy-dispersive X-ray spectra for elemental identification showed the presence of C and Ti with strong Co and S peaks from the CoS2-carbon/TiO2 composites.The composites obtained were also characterized by transmission electron microscopy and UV-Vis spectroscopy.CoS2-carbon/TiO2 composites showed excellent photocatalytic activity for the degradation of methylene blue under visible light irradiation.This was attributed to both photocatalysis on the TiO2 support and charge transfer by the carbon nanomaterial,and the introduction of CoS2 to enhance transfer of photogenerated electrons.  相似文献   

7.
A series of graphene-TiO2 composites was fabricated from graphene oxide and titanium n-butoxide(TNB) by an ultrasonic-assisted method.The structure and composition of the nanocomposites were characterized by Raman spectroscopy,BET surface area measurements,X-ray diffraction,transmission electron microscopy,and ultraviolet-visible absorption spectroscopy.The average size of the TiO2 nanoparticles on the graphene nanosheets was controlled at around 10-15 nm without using surfactant,which is attributed to the pyrolysis and condensation of dissolved TNB into TiO2 by ultrasonic irradiation.The catalytic activity of the composites under ultrasonic irradiation was determined using a rhodamine B(RhB) solution.The graphene-TiO2 composites possessed a high specific surface area,which increased the decolorization rate for RhB solution.This is because the graphene and TiO2 nanoparticles in the composites interact strongly,which enhances the photoelectric conversion of TiO2 by reducing the recombination of photogenerated electron-hole pairs.  相似文献   

8.
近几年兴起的半导体多相光催化技术在有机废水处理方面受到了人们的普遍关注[1,2]。众多的半导体光催化剂材料中,TiO2因其化学性质稳定和催化效率高而倍受青睐[3,4]。在紫外光的照射下,TiO2与H2O产生具有极强氧化能力的HO·自由基,最终可使废水中的有机物完全降解生成CO2,H2O以  相似文献   

9.
Nanostructured ZnSe-graphene/TiO2 was synthesized by a hydrothermal-assisted approach. ZnSe-graphene/TiO2 exhibited favorable adsorption of rhodamine B, a wide wavelength absorption range, and efficient charge separation. Reactive oxygen species were generated by the oxidation of 1,5-diphenyl carbazide to 1,5-diphenyl carbazone. The sonocatalytic reaction mechanism was pro-posed. These findings potentially broaden the applications of sonocatalytic technologies.  相似文献   

10.
Nanostructured ZnSe-graphene/TiO2 was synthesized by a hydrothermal-assisted approach. ZnSe-graphene/TiO2 exhibited favorable adsorption of rhodamine B, a wide wavelength absorption range, and efficient charge separation. Reactive oxygen species were generated by the oxidation of 1,5-diphenyl carbazide to 1,5-diphenyl carbazone. The sonocatalytic reaction mechanism was pro-posed. These findings potentially broaden the applications of sonocatalytic technologies.  相似文献   

11.
A one-step low-temperature hydrothermal route was developed for the synthesis of S-doped TiO2 photocatalysts from TiS2 and HCl. Crystalline TiO2 was formed and sulfur could be efficiently doped into the anatase lattice under hydrothermal conditions. When the initial TiS2 concentration is increased, the content of S-dopant and optical absorption in the visible region also increase. The photocatalytic activity of the S-doped TiO2 was evaluated through the degradation of 4-chlorophenol under visible light irradiation. Our results show that the S-doped TiO2 prepared by this hydrothermal approach possesses much higher photocatalytic activity than that obtained by the traditional high-temperature thermal annealing method.  相似文献   

12.
葛明 《催化学报》2014,35(8):1410-1417
采用简易离子交换法制备可见光驱动Ag3PO4光催化剂.通过X射线衍射、场发射扫描电子显微镜、N2吸附-脱附、紫外-可见漫反射光谱及傅里叶变换红外光谱对所制备的Ag3PO4催化剂进行表征.结果表明,在可见光照射下,Ag3PO4催化剂对罗丹明B降解表现出优越的光催化活性,但对甲基橙的降解活性低,这归因于Ag3PO4催化剂对甲基橙分子吸附量低.可见光照Ag3PO4反应体系中,空穴和超氧自由基共同发挥作用导致罗丹明B和甲基橙光催化降解.在罗丹明B的协助作用下,Ag3PO4催化剂对甲基橙的可见光催化降解活性大大增强,这是由于罗丹明B的存在可产生更多的超氧自由基,从而使甲基橙进一步降解.  相似文献   

13.
采用水热法,以纳米管钛酸为前驱物制备了Bi掺杂的TiO2,并利用X射线衍射、透射电子显微镜、X射线光电子能谱、紫外-可见漫反射光谱等手段对样品进行了表征. 以甲基橙的光催化降解为模型反应评价了样品的可见光催化性能. 结果表明,Bi离子并没有进入TiO2的晶格中,而是以BiOCl的形式存在. 所制得的BiOCl/TiO2复合物对甲基橙降解表现出较优越的可见光催化活性;当Bi/Ti摩尔比为1%,水热温度为130℃时,所制催化剂的光催化性能最佳,并对光催化活性提高的机理进行了讨论. 同时,该催化剂对4-氯苯酚降解也表现出较高的光催化性能.  相似文献   

14.
于新娈  王岩  孟祥江  杨建军 《催化学报》2013,34(7):1418-1428
在空气气氛和N2中热处理表面均匀分散有尿素和氯化钯的纳米管钛酸,制备了两个系列Pd/N共掺杂的TiO2光催化剂,并对所得样品进行了X射线衍射、透射电镜、X射线光电子能谱、紫外-可见漫反射光谱、荧光光谱和电子自旋共振等表征.结果表明,焙烧气氛对样品的形貌、晶体结构、光谱吸收、生成的氧空位浓度和可见光光催化性能的影响很大,其中在空气气氛中制备的样品光催化性能优于在N2中制备的样品.在可见光(λ≥420nm)照射下,以丙烯为模型污染物考察了样品的光催化活性,发现在空气中400℃下焙烧的样品具有最佳的可见光催化活性.另外,讨论了Pd/N共掺杂TiO2光催化剂具有可见光响应的机理,认为掺杂的Pd/N元素和制备过程中生成的氧空位是影响可见光催化性能的重要因素.  相似文献   

15.
Submicron particles of amorphous SiO2 have been used to grow Ag2S nanophases at their surfaces. SEM and TEM analysis showed morphological well-defined nanocomposite particles consisting of Ag2S nanocrystals dispersed over the silica surfaces. These SiO2/Ag2S nanocomposites were investigated as anti-fungal agents against Aspergillus niger in different experimental conditions, including as nanofillers in cellulosic fibres. The anti-fungal activity in these composite systems is suggested to result from a synergistic effect due to Ag2S anti-fungal centres and the SiO2 surfaces in promoting the adsorption of the fungus.  相似文献   

16.
采用浸渍法制备了MoO3/P25催化剂(MoO3/P25(x),x为MoO3与P25质量比),用X射线衍射、紫外-可见漫反射光谱、傅里叶变换红外光谱及拉曼光谱等手段对样品进行了表征,并用催化降解亚甲基蓝考察了催化剂在可见光区的催化活性。结果表明,MoO3在P25表面最大单层负载量对应的MoO3与P25质量比在0.1左右。单层分散的氧化钼物种与P25之间有较强的相互作用,降低了P25禁带宽度,提高了催化剂对可见光的吸收。当MoO3与P25质量比大于0.1时,会生成晶相MoO3,催化剂对可见光的吸收反而随MoO3担载量增加而降低。催化剂禁带宽度不是决定其可见光下催化降解亚甲基蓝活性的唯一因素。具有适宜禁带宽度和一定晶相MoO3含量的MoO3/P25(0.25)表现出最佳活性。  相似文献   

17.
The photoassisted degradation of two dye compounds, erythrosine and rhodamine B, has been investigated in an aqueous TiO2 dispersion under irradiation by visible light. The compounds can be easily decomposed photochemically by visible light, which provides possibly a new approach for the treatment of dye pollutants in wastewater.  相似文献   

18.
利用太阳能光催化还原CO2和H2O到燃料和化学品是一条极具吸引力但又充满挑战性的转化途径.迄今为止,只有非常有限的光催化剂已经被报道可以在可见光照射下光催化还原CO2.局部表面等离子体共振(LSPR)现象可以被用作一种有效的开发可见光催化剂的策略.贵金属Au,Ag,Pt等的LSPR现象已经被较为广泛的研究,并应用于光催化、光热、气敏等多种领域.而低价态金属自掺杂的金属氧化物,如MoO3-x和WO3-x,也被证明具有LSPR现象,可用于开发更加廉价的可见光催化剂.本文通过简单的溶剂热法成功合成了低价态Mo自掺杂的MoO3-x纳米片催化剂,并在合成过程中原位加入TiO2纳米颗粒(TiO2-NP)和TiO2纳米棒(TiO2-NT),构建了MoO3-x-TiO2纳米复合物.电镜表征显示,MoO3-x-TiO  相似文献   

19.
Edge- and corner-truncated octahedral Cu2O is successfully synthesized using an aqueous mixture of CuCl2, sodium dodecyl sulfate, NaOH, and NH2OH3·HCl. Cu2O1-xNx(150 °C, 30 min) samples are synthesized by nitridation of Cu2O using an ammonothermal process. Cu retains a formal valence state through and beyond the nitridation process. N concentration in this sample is 1.73 at%, out of which 1.08 at% is substitutional in nature. Photocatalytic activity of Cu2O1-xNx(150 °C, 30 min) sample is investigated and compared to that of pristine edge- and corner-truncated octahedral Cu2O. Results show that Cu2O1-xNx(150 °C, 30 min) sample with dominant {110} facets has a higher photocatalytic activity than the pristine Cu2O material. Higher surface energy and a greater density of the “Cu” dangling bonds on {110} facets of edge- and corner-truncated octahedral Cu2O1-xNx is the plausible reason for the observed optimum catalytic activity. Furthermore defect states induced by nitridation results in improved visible light adsorption. And also the band edge states changes which brought about by N doping. This is an interesting result since it bypasses the usual challenge faced by pristine Cu2O which have band edge states between which transitions are normally forbidden. Selective radical quenching experiments suggest that photocatalytic activity of Cu2O1-xNx is due to formation of hydroxyl radicals in water, subsequent to photogeneration of charge carriers in the photocatalyst.  相似文献   

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