Zirconia-incorporated yttria with a Lewis pair of acid–base surface sites for chemoselective dehydration of alcohols into alpha olefins

Abstract

Alpha olefins are currently made by ethylene oligomerization to a broad range of carbon number. An alternative conversion is selective alcohol dehydration in which the conventional catalyst development focused on the addition of any basic components into acidic supports. We herein demonstrated that the Zr4+ addition to Y2O3 (acid-to-base addition) was more effective than the Y3+ addition to ZrO2 in alcohol dehydration to alpha olefins. The zirconia-incorporated yttria with 4 mol% Zr (named 4ZIY) was structurally more stable than the yttria-stabilized zirconia (YSZ) counterpart. Moreover, the 4ZIY showed a high purity of alpha olefins when various C4 and C6 alcohols were used. Catalyst characterization works revealed that the 4ZIY contains a large amount of strong Lewis base sites, which is associated with oxygen vacancy, with a little Lewis acid sites. Consequently, the 4ZIY is suggested to have the favorable acid–base pair for the conversion of alcohols to alpha olefins.