共查询到19条相似文献,搜索用时 130 毫秒
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钙钛矿型CaxSr1-xFeO3的光催化活性研究 总被引:1,自引:0,他引:1
首先利用柠檬酸溶胶-凝胶法制备了钙钛矿型化合物SrFeO3纳米晶及其掺杂产物粉末,然后利用差热分析找出前驱体干凝胶的灰化温度和焙烧温度分别为400、700℃,利用XRD、TEM等检测手段对催化剂晶体进行了表征。结果表明,柠檬酸溶胶-凝胶法制备的SrFeO3复合氧化物的粒径50~70 nm,属于纳米级;利用紫外-可见光分光光度计测定了SrFeO3对亚甲基蓝溶液的催化性能,发现Ca的掺杂能够明显提高催化剂的催化性能,并得到Ca掺杂5%时(摩尔分数)的催化性能最佳。 相似文献
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通过溶胶-凝胶法分别制备了La^3+-Ce^3+共掺杂及Fe^3+-Ce^3+共掺杂的TiO2纳米粉体。利用透射电镜(TEM)对粒子的形貌和粒径进行了表征,并用分光光度法研究了粉体对甲基橙溶液的降解。通过分析共掺杂离子的掺杂量和样品的煅烧温度对降解率的影响,对所制备粉体的光催化性能进行了研究。结果表明,La^3+-Ce^3+共掺杂的TiO2粉体其光催化活性有较大提高。 相似文献
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以水合肼为掺杂氮源,采用微波辐照对锐钛矿型纳米二氧化钛(TiO2)进行改性,考察了掺氮纳米二氧化钛的光催化性能,并用XPS、Uv-Vis、XRD.TEM等方法对其进行了表征。结果表明,在nc:nno2:n水合阱=0.5:1:11、微波辐照功率为500W、微波辐照时间为20min的条件下所得粉体的光催化性能最佳,在可见光下具有较高的反应活性,表明微波掺氮改性纳米二氧化钛大幅提高了其光催化性能;微波辐照后,氮原子取代了二氧化钛粉体表面少量氧原子,TiO:的粒径和晶型均保持不变,但吸收边明显向可见光方向偏移。 相似文献
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制备了3种不同粒径的Ag纳米颗粒,将它们分别掺入二氧化钛溶胶,制备成复合二氧化钛薄膜,利用TEM测定了Ag粒子的大小,测量TiO2复合膜的光电流,以亚甲基蓝降解反应评价了Ag/TiO2薄膜的光催化活性,结果表明,负载不同粒径Ag纳米粒子后,TiO2薄膜的光电流和光催化活性均得到一定程度的提高。当负载平均粒径6.9nm的Ag粒子后,薄膜具有最高的光电流和最强的光催化活性。 相似文献
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以尿素为均匀沉淀剂、硫酸氧钛为原料制备粒径可控、分散性良好的纳米二氧化钛粉体。系统地研究了制备条件对粒径大小、粒子形貌的影响,探讨了均匀沉淀法形成纳米二氧化钛粉体的机理、晶体成长和晶型转化动力学以及光催化性能,并列举了作为光触媒的应用实例。 相似文献
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在光催化还原反应体系中引入超声场制备了Ag/TiO2光催化剂.考察了超声频率、功率等对还原反应的影响,对所制得的负载型Ag/TiO2光催化剂进行微观性能表征,并以低浓度苯酚溶液为降解对象进行光催化氧化活性表征.结果表明,超声场的引入对光催化还原反应有很好的强化作用,促进光催化还原反应的最佳超声频率为45 kHz,同时,Ag 还原率随着超声功率的增加而增大.所制得的Ag/TiO2光催化剂具有粒径小、光催化活性高的特点. 相似文献
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可见光活性负载型Fe2O3/TiO2光催化剂的制备 总被引:2,自引:2,他引:0
以FeCl3·6H2O和TiOSO4为原料,尿素为沉淀剂,采用均匀共沉淀法制备了Fe3 掺杂的纳米TiO2粉体,并通过X射线衍射、透射电镜分析及观察粉体的相结构、形貌和粒径.以甲基橙溶液为降解对象,考察了掺杂后的粉体在紫外和可见光作用下的光催化性能并对其机理进行了探讨.结果表明:Fe3 部分固溶于TiO2的晶格;当Fe3 掺杂量<0.8%(摩尔分数,下同)时,随铁离子掺入量的增加,TiO2的光催化性能提高;当Fe3 掺杂量为0.8%时,复合粉体的光催化性能提高15%以上;当Fe3 掺杂量>0.8%时,随铁离子掺入量的增加,TiO2的光催化性能降低,而当Fe3 掺杂量>1.2%时,粉体的光催化性能受到抑制,低于纯TiO2粉体. 相似文献
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《Catalysis communications》2007,8(6):963-966
Nanostructured SrFeO3−x was prepared by citrate under ultrasonic radiation. The photocatalytic activity was investigated with phenol as the photocatalytic degradation modal reactant under 450 W high pressure mercury lamp. The catalyst was characterized by XRD, TEM, XPS, UV–vis DRS. The results indicate that the structural and photocatalytic properties of SrFeO3−x were greatly improved by ultrasonic radiation, and its particles are well-decentralized, in smaller size, with red-shifted band edge of UV–vis adsorption spectra than that of the samples prepared by conventional method. It was supposed that the presence of different photocatalytic properties among these perovskite compounds was derived from the structural differences among them. 相似文献
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用硝酸银和钛酸正丁酯为原料,采用溶胶-凝胶-微波辐射干燥法合成银掺杂TiO_2光催化剂TiO_2-Ag。为了提高催化剂的光催化活性和降解有机污染物的速率,用微波辅助Ti O2-Ag光催化剂降解有机污染物。通过扫描电子显微镜、红外光谱法、紫外可见光谱法和荧光光谱法对TiO_2-Ag催化剂进行测试和表征。以甲基橙为有机污染物,分别在太阳光照射和微波、紫外、紫外-微波条件下降解甲基橙以考察催化剂的光催化活性。结果表明,TiO_2-Ag光催化剂最佳制备条件为:银掺杂量n(Ag+)∶n(Ti~(4+))=0.003,离子液体用量3.0 m L,微波干燥功率210 W,微波干燥时间20 min,焙烧温度650℃,焙烧时间3 h,此条件下制备的TiO_2-Ag光催化剂在太阳光照射4 h下,紫外光照、微波辐射和紫外光照-微波辐射分别辐射55 min后,甲基橙降解率分别为98.70%、98.79%和99.05%。 相似文献
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Chang Wook Oh Gun-Dae Lee Seong Soo Park Chang-Sik Ju Seong-Soo Hong 《Korean Journal of Chemical Engineering》2005,22(4):547-551
TiO2 nanoparticles were prepared by hydrolysis of TTIP (titanium tetraisopropoxide) using an ultrasonication technique coupled
with a sol-gel method. The physical properties of nanosized TiO2 were investigated. The photocatalytic degradation of 4-nitrophenol was studied by using a batch reactor in the presence of
UV light. The crystallite size of the anatase phase is increased with an increase of REtOH ratio (EtOH/H2O molar ratio). The particles’ crystallite size prepared with and without ultrasonic irradiation is marginally different.
Those particles prepared with ultrasonic irradiation show a higher activity on the photocatalytic decomposition of 4-nitrophenol
compared to those prepared without ultrasonic irradiation. The photocatalytic activity decreases with an increase of REtOH ratio. In addition, the photocatalytic activity shows the highest value on the titania particle calcined at 500 ‡C.
This paper was presented at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November
3 and 4,2004. 相似文献
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通过高温固相反应合成了铌酸盐KCa2Nb3O10及Cr^3+和Mo^6+掺杂(摩尔分数5%)的KCa2Nh3O10,并通过离子交换反应制备出HCa2Nb3O10及Cr^3+和Mo^6+掺杂的HCa2Nb3O10采用X射线衍射、原子吸收光谱、扫描电镜等对所制得的样品进行了表征.在甲醇为电子给体、Pt为助催化剂的情况下,研究了催化剂HCa2Nb3O10及Cr^3+和Mo^6+掺杂的HCa2Nb3O10在紫外光辐射下分解水产氢的光催化活性,并讨论了引起催化剂活性差异的原因, 相似文献
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以1-甲基咪唑和氯代正丁烷为原料,合成1-丁基-3-甲基咪唑氯盐离子液体;以醋酸锌[Zn(Ac)2]、硫酸锌(ZnSO4)和氯化锌(ZnCl2)为锌源,在1-丁基-3-甲基咪唑氯盐离子液体和丙氨酸体系中与硝酸铈反应,经水热合成法制备得到Ce掺杂的纳米ZnO。采用扫描电子显微镜(SEM)、紫外-可见光吸收光谱(UV-Vis)、X射线衍射仪(XRD)、X射线光电子能谱分析(XPS)和红外光谱(FT-IR)对产品进行表征。以亚甲基蓝(MB)为目标降解物,采用UV-Vis检测,考察了Ce掺杂的纳米ZnO的光催化活性。研究表明,焙烧温度对光催化的晶体结构和光催化活性产生较大的影响;2%Ce/ZnO、焙烧温度为500℃、催化时间为30 min、亚甲基蓝用量0.05 g、pH值为10时降解率可达99.5%以上。 相似文献
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Elham Einafshar Zahra Khodadadipoor Mostafa Fazli Nafiseh Einafshar Javad Mohebbi Zinab Sogol Asaei 《International Journal of Applied Ceramic Technology》2021,18(6):2064-2074
In this research, Ag-Al2O3 nanostructures have been prepared via combustion synthesis and ammonium acetate and urea have been applied as fuels. The prepared Ag-Al2O3 nanostructures were characterized by DTA, XRD, SEM, TEM, and BET spectroscopy. The effect of different ratios of silver to alumina and fuel percentage on morphology and particle size of prepared products were investigated. The results showed that using ammonium acetate fuel led to the production of Ag-γ-Al2O3 nanocompounds, while using urea produced Ag-α-Al2O3. Also, the photocatalytic activity of Ag-Al2O3 nanostructures for Congo red degradation was evaluated by UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity of Ag-Al2O3 was examined under UV-Vis irradiation and showed significant photocatalytic efficiency. 相似文献