Acid-base bifunctional catalysis by ZrO2 and its mixed oxides

Abstract Examples of acid-base bifunctional catalysis by ZrO2 and its mixed oxides are summarized. The hydrogenation of olefins, carbon monoxide and aromatic carboxylic acids over ZrO2 are also examples of acid-base bifunctional catalysis which occur by heterolytic splitting of a hydrogen molecule (H2) into a proton (H+) and a hydride ion (H−) on the acid-base pair sites. Industrial applications of ZrO2 catalysts are demonstrated, the importance of acid-base bifunctional catalysis by ZrO2 and its mixed oxides being emphasized.