Influence of gelation and calcination temperature on the structure-performance of porous VOX-SiO2 solids in non-oxidative propane dehydrogenation

VO X -doped porous SiO 2 solids (VO X -SiO 2 ) were synthesized at different gelation and calcination temperatures through an in-situ one-step synthesis and evaluated by non-oxidative propane dehydrogenation (PDH), exhibiting excellent catalytic performance. VO X -SiO 2 catalysts were characterized by XRD, low-temperature N 2 adsorption/desorption, SEM, TEM, UV–Vis, Raman, XPS, NH 3 -TPD, H 2 -TPR, and TGA. The structural and performance results for the catalysts reveal that gelation temperature has only a slight effect on the surface acidity, textural properties and VO X species dispersion of VO X -SiO 2 catalysts within a reasonable temperature range (30–60 °C). The 60-VO X -SiO 2 -580 catalyst, with a gelation temperature of 60 °C, a calcination temperature of 580 °C, and prepared by the one-step synthesis method, obviously shortens gelation process time by half compared to catalyst gelled at 30 °C and exhibits superior catalytic performance for PDH . Over high gelation temperature (≥75 °C) leads to the loss of integrity and decreases catalytic activity of the VO X -SiO 2 catalysts. Compared with the VO X -MCM-41 catalyst prepared by a one-step hydrothermal method, VO X -SiO 2 catalysts exhibit better catalytic activity and stability. Importantly, at a reaction temperature of 580 °C, the 60-VO X -SiO 2 -580 catalyst exhibits remarkable long-term catalytic stability in the eight reaction-regeneration cycles for PDH. Its propane conversion shows a slow decrease from 55% to 45% for a 4 h reaction duration, but the propene selectivity remains at approximately 91%. The results of this work will be beneficial for further industrial development and application of porous VO X -SiO 2 solids in catalysis.