Recent Advances on TiO₂‐ZrO₂ Mixed Oxides as Catalysts and Catalyst Supports

Abstract

This is the first review of titanium dioxide‐zirconium dioxide (TiO₂‐ZrO₂) mixed oxides, which are frequently employed as catalysts and catalyst supports. In this review many details pertaining to the synthesis of these mixed oxides by various conventional and nonconventional methods and their characterization by several techniques, as reported in the literature, are assessed. These mixed oxides have been synthesized by different preparative analogies and were extensively characterized by employing various spectroscopic and nonspectroscopic techniques. The TiO₂‐ZrO₂ mixed oxides are also extensively used as supports with metals, nonmetals, and metal oxides for various catalytic applications. These supported catalysts have also been thoroughly investigated by different techniques. The influence of TiO₂‐ZrO₂ on the dispersion and surface structure of the supported active components as examined by various techniques in the literature has been contemplated. A variety of reactions catalyzed by TiO₂‐ZrO₂ and supported titania‐zirconia mixed oxides, namely; dehydrogenation, decomposition of chlorofluoro carbons (CFCs), alcohols from epoxides, synthesis of ϵ‐caprolactam, partial oxidation, deep oxidation, hydrogenation, hydroprocessing, organic transformations, NO_x abatement, and photo catalytic VOC oxidations that have been pursued in the literature are presented with relevant references.

Keywords:

• TiO₂‐ZrO₂ mixed oxide
• ZrTiO₄
• Coprecipitation
• Sol‐gel
• Acid‐base properties
• Dehydrogenation
• Decomposition of CFCs
• Oxidation
• Hydrogenation
• Hydroprocessing
• Organic transformations
• NO_x abatement
• Photo catalytic activity

Acknowledgment

Support from the Department of Science and Technology, New Delhi, is gratefully acknowledged (SERC Scheme: SP/S1/H‐20/98).