Designed Formation of Polyoxometallate-Based Mesoporous Titania Composites by a Solvent-Free Chemical Self-Assembly Method for Oxidative Desulfurization of Diesels

Abstract

The construction of crystalline TiO2 with uniform mesoporous architecture plays a key role in its catalytic performance improvement. However, the resulting porous TiO2 composite is liable to form a disordered pore structure and have a narrow pore size and low porosity after a high-temperature-induced crystallization process, leading to a serious decrease in its catalytic efficiency. Here, a series of polyoxometalate (POM)-modified TiO2 catalysts with a confined mesostructure have been realized by a rapid and solvent-free self-assembly strategy, oriented by polyethyleneimine (PEI) polymer. TEM and N2 adsorption analyses demonstrate that the as-fabricated mesoporous composites possess remarkable porous properties (i.e., 260.5 m2 g–1 and 0.3989 m3 g–1). In addition, the nanomesoscopic structure of catalysts can be further tuned by varying molecular interactions between polyethyleneimine, titanium oligomers, and POMs. The as-fabricated POM-based TiO2 catalysts provide connected and large mesochannels for reactant molecules in the inner surface and enhance the dispersity of POM species in the TiO2 matrix, which exhibits excellent catalytic efficiency in the oxidative desulfurization reaction of dibenzothiophene at room temperature.