Acidity/basicity, electron donor properties and catalytic activity of sulphate modified ceria

Abstract

<span style="font-size:12.0pt;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:calibri;mso-fareast-theme-font:minor-latin;color:#121212;="" mso-ansi-language:en-in;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The <span style="font-size:12.0pt;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:calibri;mso-fareast-theme-font:minor-latin;color:#222222;="" mso-ansi-language:en-in;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">changes in surface <span style="font-size:12.0pt;font-family:" times="" new="" roman","serif";="" mso-fareast-font-family:calibri;mso-fareast-theme-font:minor-latin;mso-ansi-language:="" en-in;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">acidity/basicity and catalytic activity of cerium oxide due to surface modification by sulphate ion have been investigated. Electron donor properties of both the modified and unmodified oxides have been studied using electron acceptors of various electron affinity values, viz. 7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrachloro-1,4-benzoquinone, <i style="mso-bidi-font-style:normal">p</i>-dinitrobenzene and <i style="mso-bidi-font-style:normal">m</i>-dinitrobenzene in order to find out whether the increase in acidity on suphation is due to the generation of new acidic sites or they are formed at the expense of some of the basic sites. The surface acidity/basicity has been determined using a set of Hammett indicators. The data have been correlated with the catalytic activity of the oxides for esterification of acetic acid using 1-butanol, reduction of cyclohexanone with 2- propanol and oxidation of cyclohexanol using benzophenone.</span></span></span>