Microwave-Assisted Facile Sol–Gel Synthesis of WO₃-Based Silica Catalysts for Enhanced Activity in Glycerol Dehydration

Abstract

WO3 is a promising catalyst for the production of acrolein from glycerol due to its high activity and selectivity. In this study, various metal oxides (W, Zr, and Nb) over colloidal silica (cSiO2) catalysts were obtained using a novel microwave-assisted synthesis method. The enhancement in the sol–gel grafting of metal oxides onto the cSiO2 support was achieved by microwave irradiation (MW) and compared to the conventional heating (CH). WO3-cSiO2 catalysts synthesized by microwave-assisted facile sol–gel synthesis were tested in the gas-phase glycerol dehydration reaction. The best catalytic performance (52.4% acrolein yield) was obtained over a 25%W-cSiO2 sample prepared by the MW method. The best yield results were obtained with a B/(B + L) ratio over 0.50 and with an optimum medium-strength acidity. The activity loss was correlated with the high-strength surface acidity.

Transition Metal Catalysts for the Glycerol Reduction: Recent Advances

“…[117] Dehydration of GL to Acr was achieved using a WO 3 /ZrO 2 @SiC catalyst, under microwave irradiation, with better results compared to conventional electric heating: at 523 K the Acr selectivity reached over 70 % with complete GL conversion under microwave, against 54 % by conventional heating. [118] The microwave was used again to prepare, by sol-gel method, a 25 %WO 3 -SiO 2 that catalyzed the Acr formation (54 % selectivity at full conversion) in a fixed-bed reactor at 573 K. [119] The microwave raised the concentration of medium-strength BAS and led to a high amount of cubic WO 3 crystals which increased the catalyst stability.…”

Green synthesis of silica gel adsorbents: microwave boosts silanol groups for improved moisture uptake

“…Microwave-assisted synthesis has emerged as a powerful tool for material synthesis (Zengin et al, 2023) (Santos et al, 2021) due to its rapid processing, lower energy consumption, and enhanced control over material properties (Istrati et al, 2021) (Bucek et al, 2019). However, limited research has been conducted on tailoring the properties of silica gel, specifically the silanol group content, through microwave synthesis for improved moisture adsorption (Zhuravlev & Potapov, 2006).…”