Rutile – A superior support for highly selective and stable Pd-based catalysts in the gas-phase acetoxylation of toluene

Nanofibrous TiO2 produced using alternating field electrospinning of titanium alkoxide precursors: crystallization and phase development

High-yield, free-surface alternating field electrospinning (AFES) was effectively used in the fabrication of titanium oxide nanofibrous materials from the precursors based on titanium alkoxide and a blend of polyvinylpyrrolidone and hydroxypropyl cellulose. The alkoxide/polymer mass ratio in the precursor solution has significant effects on the precursor fiber production rate as well as the structure of resulting TiO2 nanofibers after thermal processing of precursor fibers at temperatures from 500 to 1000 °C. Within the range of tested process parameters, the best fiber production rate of ∼5.2 g h-1 was achieved, in terms of the mass of crystallized TiO2 nanofibers, with the precursor that corresponded to 1.5 : 1 TiO2/polymer mass ratio. TiO2 nanofibers produced by calcination at 500 °C for 3 h had 100-500 nm diameters and were composed of anatase (20-25 nm crystallite size) with rutile content 0.1-6.0 mol%, depending on the precursor composition. A considerable amount of anatase phase (up to 80 mol%) can be retained after thermal processing of TiO2 nanofibers at 750 °C for 3 h. A nanofibrous material composed of smooth and long, predominantly monocrystalline rutile, fibrous segments was produced at 1000 °C from the precursor with 2.5 : 1 TiO2/polymer mass ratio.

Nature of surface carbon species and pathways of their formation in the heterogeneously catalysed acetoxylation of toluene

The origins of surface carbon species in the acetoxylation of toluene to benzyl acetate over Pd–Sb/TiO₂ catalyst and their formation pathways were systematically investigated.

Titanium dioxide as a catalyst support in heterogeneous catalysis

The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO₂) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO₂ supported metal catalysts have attracted interest due to TiO₂ nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO₂ was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO₂ supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO₂ as a support material for heterogeneous catalysts and its potential applications.