TiO2 Nanotubes for Hydroformylation of Vinyl Acetate from Syngas

Abstract

TiO₂ nanotubes (TNTs) have emerged as promising supports for heterogeneous catalysts due to their unique physicochemical properties, including high surface area, ion-exchange capacity, and structural stability. This review focuses on the work of Chuai et al., who systematically explored TNTs as supports for Rh-based catalysts in the hydroformylation of functionalized olefins, particularly vinyl acetate, using syngas (CO/H2). Their studies demonstrated that modifying TNTs with transition metal (Ru), alkali/alkaline earth cations (Li⁺, Na⁺, K⁺, Mg2⁺, Ca2⁺, Sr2⁺), and rare-earth metal (La3⁺) significantly enhances catalytic activity, selectivity, and turnover frequency (TOF). Key findings include the synergistic effects of Rh-Ru systems, the promotional role of alkali cations in CO adsorption, and the exceptional performance of La-decorated Rh/TNTs (TOF = 5796 h^-1). Beyond hydroformylation, the potential applications of TNTs in other catalytic processes, such as Fischer-Tropsch synthesis, hydrogenation, and environmental catalysis, are discussed. This review highlights the versatility of TNTs as catalyst supports and provides insights into future research directions.