The surface acid strength distribution in bismuth tungstate catalysts with Bi/W ratios of 2/3, 1/1, 2/1 and 6/1 has been investigated. The results are interpreted attributing higher acidities to W-O-W bonds and lower acidities to W=O bonds. An apparent correlation is observed between the surface acidities of the catalysts and their activities in the oxidation and ammoxidation of propylene and 1-butene. © 1977 Akadémiai Kiadó.

S SINHAMAHAPATRA

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

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Correlation between the surface acidity and activity of bismuth tungstate catalysts

Reaction Kinetics and Catalysis Letters

Bismuth tungstate catalysts with Bi/W ratios 2/3, 1/1, 2/1, and 6/1 have been investigated after various heat treatments by room temperature X‐ray analysis. The activity and selectivity of Bi2WO6 catalyst are suggested to be connected with the presence of corner sharing W—O octhedra in the bulk of the solid that give rise to tetragonal pyramidal W—O sites at the surface. The very low activity of Bi2(WO4)3 is attributed to edge‐shared octahedral coordination of W while the same of Bi6WO12 is due to tetrahedral coordination of W. The inactivity of Bi2W2O9 may be associated with its typically low oxidation power. The promoting influence of Bi2O3 is to enforce a structural situation on W—O so that W may be present in a tetragonal pyramidal 5‐configuration. Copyright © 1977 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim

Journal	Reaction Kinetics and Catalysis Letters
Publisher	Kluwer Academic Publishers
ISSN	0133-1736