MoO_3/γ-AI_2O_3,MoO_3/TiO_2, MoO_3/SiO_2的氨溶性质及表面状态的研究

doi:10.3866/PKU.WHXB19850306

CORC > 北京大学 > 化学与分子工程学院

	MoO_3/γ-AI_2O_3,MoO_3/TiO_2, MoO_3/SiO_2的氨溶性质及表面状态的研究; STUDY ON THE EXTRACTION OF MOLYBDENUM AND SURFACE STATE FOR MoO3 SUPPORTED ON THE SURFACE OF gamma-Al2O3, TiO2 AND SiO2
	桂琳琳 ; 钟边笑 ; 唐有祺
刊名	物理化学学报
	1985
关键词	四面体空隙八面体空隙实验手段系列样品结构状态烘烤温度分率稳定态浸渍法 MoO_3/SiO_2
DOI	10.3866/PKU.WHXB19850306
英文摘要	本文用浸渍法制备了不同含量的MoO_3/γ-Al_2O_3、MoO_3/TiO_2、MoO_3/SiO_2系列样品,用氨溶、水溶,XPS、XRD等实验手段对这三个体系进行了研究。氨溶实验表明MoO_3在γ-Al_2O_3和TiO_2表面呈单层分散,其分散阈值(即最大分散量)与XPS强度比法,XRD相定量法所测结果基本一致。这二个体系氨溶曲线在阈值前斜率分别为0.71和0.66,说明分散在γ-Al_2O_3或TiO_2上的单层MoO_3分为氨水可溶和不可溶二种状态,这二种状态以确定的比例共存于阀值前的整个浓度区间。这一现象也为氮溶前后样品XPS强度比的比值所证实。实验还表明MoO_3/γ-Al_...; MoO3/gamma-Al2O3, MoO3/TiO2 and MoO3/SiO2 samples prepared by impregnation method have been studied by various techniques, including XPS, XRD, and extraction of molybdenum with ammonium solution or water. The result of extraction of molybdenum with ammonium solution shows that if the MoO3 content is lower than certain amount, a constant fraction (71% for MoO3/gamma-Al2O3 system and 66% for MoO3/TiO2 system) of MoO3 can be dissolved in 3wt.% solution of NH4OH and if the MoO3 content is higher than that amount, surplus MoO3 can be dissolved completly. The turning point of both systems is in line with the dispersed threshold value obtained by XPS and XRD methods. It means that MoO3 disperses as monolayer on these carriers before the turning point and forms crystallite grain after that. The constant dissolved fraction of MoO3 in ammonium solution shows that there are two different surface species in monolayer state, one is soluble and another is not. Two kinds of species coexist in monolayer With constant ratio, which have also been confirmed by XPS experiment for samples before and after extraction. The samples which soluble species was thoroughly removed were recalcined at certain temperture and again soaked into ammonium solution a lot of soluble species were reproduced then. The dissolved fraction of them approched that of the samples before extraction with a rise in temperature and a prolonging of time. We suggest that the monolayer dispersed MoO3 on gamma-Al2O3 or TiO2 surface can be divided into two kinds of surface species, one is located in octahedral vacancy of O-2- and another in tetrahedra vacancy. They join each other by sharing oxygen ions and form monolayer aggregate patch in a special way (similar to gamma-molybdena MoO4). It is a thermodynamic favorable state in both systems. For MoO3/SoO(2) samples, however, the situation is quite different. All of MoO3 species in the monolayer iis soluble thoroughly in ammonium solution. It shows that the mutual interaction between MoO3 in monolayer state and the surface of SiO2 carrier is mach weaker than that of two other systems.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000207567900006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; SCI(E); 3; 03; 222-231; 1
语种	中文
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/312653]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	桂琳琳,钟边笑,唐有祺. MoO_3/γ-AI_2O_3,MoO_3/TiO_2, MoO_3/SiO_2的氨溶性质及表面状态的研究, STUDY ON THE EXTRACTION OF MOLYBDENUM AND SURFACE STATE FOR MoO3 SUPPORTED ON THE SURFACE OF gamma-Al2O3, TiO2 AND SiO2[J]. 物理化学学报,1985.
APA	桂琳琳,钟边笑,&唐有祺.(1985).MoO_3/γ-AI_2O_3,MoO_3/TiO_2, MoO_3/SiO_2的氨溶性质及表面状态的研究.物理化学学报.
MLA	桂琳琳,et al."MoO_3/γ-AI_2O_3,MoO_3/TiO_2, MoO_3/SiO_2的氨溶性质及表面状态的研究".物理化学学报 (1985).