Novel tungsten-incorporated mesoporous silicates synthesized via evaporation-induced self-assembly: Enhanced metathesis performance

Tungsten-incorporated mesostructured silicates were successfully synthesized by evaporation-induced self-assembly (EISA) method. Tungsten loadings from 2.9 to 22.2 wt% were achievable, with the corresponding BET surface areas decreasing from 520 to 284 m(2)/g at increased W loading. The W-EISA samples displayed amorphous ordered pore structure with an average pore size distribution of 2.3-3.3 nm. Hydrated isolated tetrahedral [WO4](2-) species and hydrated octahedral polytungstate species were identified from diffuse reflectance UV/Vis spectra under ambient conditions. Uniform distribution of W species, mostly located near the surface, was evident from XPS W 4f photoelectron image. At 450 degrees C and 1 atm, for the reaction of ethylene + 2-butene metathesis to form propene, the W-EISA catalysts outperform either impregnated catalysts (WO3/SiO2 and WO3/KIT-6) or one-pot synthesized W-KIT-6 catalyst, implying better W utilization in the W-EISA catalyst. (C) 2017 Elsevier Inc. All rights reserved.