{"title":"Synthesis and characterization of several La3+ and Sr2+ vanadates, active as methanol oxidation catalysts","authors":"J.E. Sueiras , P. Salagre, J.L.G. Fierro","doi":"10.1016/0168-7336(89)80023-3","DOIUrl":null,"url":null,"abstract":"<div><p>Substitution of Sr<sup>2+</sup> for La<sup>3+</sup> in strontium orthovanadates gives materials with interesting bulk and surface properties.</p><p>The results indicate that there are correlations between increasing selectivities to formaldehyde and (i) the decreasing crystallinity of the mixed vanadates, (ii) the increasing La migration from the surface towards the bulk, (iii) the decreasing initial temperature of reduction of V<sup>5+</sup> in the catalysts.</p><p>The migration of the La<sup>3+</sup> could leave the oxygen of the crystal structure more accessible to the reducing hydrogen (during TPR measurements) and to the reactants in the catalytic methanol oxidation. This La<sup>3+</sup> migration into the bulk may also be the cause of the loss of the crystallinity. In addition the La<sup>3+</sup> vacancies in the isostructural mixed vanadate catalysts should be responsible for their selectivities in the oxidation of methanol to formaldehyde.</p></div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"7 2","pages":"Pages 131-141"},"PeriodicalIF":0.0000,"publicationDate":"1989-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(89)80023-3","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Reactivity of Solids","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0168733689800233","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 1
Abstract
Substitution of Sr2+ for La3+ in strontium orthovanadates gives materials with interesting bulk and surface properties.
The results indicate that there are correlations between increasing selectivities to formaldehyde and (i) the decreasing crystallinity of the mixed vanadates, (ii) the increasing La migration from the surface towards the bulk, (iii) the decreasing initial temperature of reduction of V5+ in the catalysts.
The migration of the La3+ could leave the oxygen of the crystal structure more accessible to the reducing hydrogen (during TPR measurements) and to the reactants in the catalytic methanol oxidation. This La3+ migration into the bulk may also be the cause of the loss of the crystallinity. In addition the La3+ vacancies in the isostructural mixed vanadate catalysts should be responsible for their selectivities in the oxidation of methanol to formaldehyde.
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