Fuel, Vol.226, 148-155, 2018
Three-dimensional ordered phosphotungstic acid/TiO2 with superior catalytic activity for oxidative desulfurization
A series of phosphotungstic acid (HPW)/TiO2 materials with three-dimensional continuous and ordered macroporous structure, ranging from 130 nm to 300 nm in size, are synthesized by colloidal crystal templates and used as catalysts for oxidative desulfurization (ODS) of model oil. The structure and properties of 3DOM HPW/TiO2 catalysts are characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), N-2 adsorption-desorption isotherms, inductively coupled plasma-optical emission spectrophotometer (ICP) and fourier transform infrared spectra (FT-IR). Characterization results demonstrate that all the HPW/TiO2 samples possess a large BET surface area and three-dimensional ordered macroporous structure with Keggin-type HPW dispersed homogeneously in TiO2 framework. 3DOM HPW/TiO2 with an average pore diameter around 250 nm presents the highest catalytic activity for dibenzothiophene (DBT), which can be attributed to the combination of its large enough macropores allowing for efficient mass transport and its high surface area enabling sufficient exposure of catalytic active sites. Furthermore, the catalyst is recovered and reused for seven runs with no obviously decrease in catalytic activity.