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Study On Morphologic Control And Catalytic Property Of Nano/micro-meter Oxides And Sulfides

Posted on:2007-09-06Degree:DoctorType:Dissertation
Country:ChinaCandidate:G XieFull Text:PDF
GTID:1101360182495092Subject:Inorganic Chemistry
Abstract/Summary:PDF Full Text Request
ZnO and CuO with different morphologies have been prepared via facile hyhro/solvo-thermal and solution methods. Micrometer ZnO with rugby, ball and screwedcap-like morphologies were obtained by changing the ratio of Zn(NO3)2 to methanol or ethanol via solvothermal method, and the possible mechanisms discussed. Rose-like CuO has been prepared using precursor [Cu(NH3)4](NO3)2 via hydrothermal synthesis while ball-like CuO obtained as the reaction parameters changed. Nano-CuO with dandelion-like morphology has been attained by employing CuCl2 in 50% ammonia via hydrothermal synthesis. Adding surfactants to the reaction system, chrysanthemum-like CuO was obtained with OP and ball-like CuO with potassium oleate.The catalytic activities of ZnO, CuO and MnO2 with different morphologies for AP (ammonium perchlorate) have been investigated by DSC means, and the following conclusion have been made: (A) The surface structure exhibited more effects than particle size on catalyzing AP. (B) Cu(OH)2/CuO prepared by employing KOH/NH3 showed excellent catalytic feature, and the peak temperature of AP is of 329.27 ℃. (C) All MnO2 prepared by various methods on catalyzing AP showed single-exopeaks. (D) The catalytic performance of MnO2 nanorods prepared with MnSO4 and KMnO4 via hydrothermal route for AP showed that the lowest peak temperature was 288.70 ℃ compared with the reference reports. (F) Rather than particle size, the morphology plays a great influence on the catalytic property.Employing the complexes with different structures and thiourea in preparing CuS, we found: (1) It is at the temperatures higher than 150 ℃ that CuS microwires with diameter of 1μm and length of 20μm have been obtained by using Cu(2-pac)2 or Cu(2-pac)2(H2O)2 as metal source, while at the temperatures lower than 130 ℃, the reddish brown complex was obtained that is isostructural with the complex prepared by KSCN instead of thiourea. Based on the crystal structure analysis, the possible transformation mechanism of thiourea was proposed. (2) Reaction of the complex [Cu2(ip)2(phen)2H2O]n or [Cu(nip)(phen)]n and thiourea led to CuS with a diameter of 2-3 μm under hydrothermal condition at 180 ℃. (3) Selecting the mixed-valence complex [Cu2(2-pac)2(NO3)(H2O)]n as metal source reacting with thiourea, nano flowers CuS was observed.Thermolyses of the precursor complex M(S2CNEt2)3 (M = EHn Sb) were carried out in tube furnace under a flow of dry nitrogen and Teflon-lined autoclave in solventfree, respectively. It is in tube heater that microrods M2S3 has been yielded while at the Teflon-lined autoclave in solventless, nanorods Bi2S3 with diameters of 100-300 nm and lengths of 3-7 um obtained. Addition of a little amount of ammomium salt to the reaction system resulted in dandelion-like M2S3, and the possible mechanism of formation was assumed. In addition, Selecting M^CNC^g^ (M = Bk Sb) as the precursor, nanobelts SbgOnBr2 and nanoslices BiOBr were obtained in water/trichloromethane/CTAB via hydrothermal emulsification synthesis.
Keywords/Search Tags:precursor, hydro/solvo-thermal synthesis, ammonium perchlorate (AP), catalyse, DSC, oxides, sulfides
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