WVOx Supported on Industrial Al2O3, SiO2, AC, TiO2–Al2O3 for Catalytic Dehydration of Gas-Glycerol to Acrolein

Abstract

WVO_x bi-metal oxides supported on the cost-effective industrial mesoprous Al₂O₃, SiO₂, active carbon (AC), and TiO₂–Al₂O₃ with different specific surface areas (WVO/Al₂O₃, WVO/SiO₂, WVO/AC, and WVO/TiO₂–Al₂O₃) were designed and prepared through co-impregnation method for large-scale bio-glycerol dehydration to acrolein. The XRD, BET, SEM–EDS, XPS, and NH₃-TPD characterization results revealed the WO₃–VO_x (V⁴⁺/V⁵⁺) species existed with better dispersion, lower molar ratio of V⁴⁺/V⁵⁺, and enhanced strength of surface acid sites on the developed mesoporous TiO₂–Al₂O₃ in comparison with that on the mesoporous Al₂O₃, SiO₂, and AC, demonstrating strong interaction of WO₃–VO_x species with the TiO₂–Al₂O₃ support and accounting for the acrolein selectivity over catalysts following the order of WVO/TiO₂–Al₂O₃ (75.8%) > WVO/AC (71.2%) > WVO/SiO₂ (55.3%) > WVO/Al₂O₃ (42.8%). Over the WVO/TiO₂–Al₂O₃, gas-glycerol conversion reached above 97.0% with acrolein selectivity of about 75.0% under the gas hourly space velocity (GHSV) of 120–360 h⁻¹, and maintained an improved catalytic stability.

Graphical Abstract

The acrolein selectivity over the prepared catalysts followed the order of WVO/TiO₂–Al₂O₃ > WVO/AC > WVO/SiO₂ > WVO/Al₂O₃, Among them, the WVO/TiO₂–Al₂O₃ catalyst demonstrated a low V⁴⁺/V⁵⁺ ratio, surface acid sites, and exceptional catalytic performance with a gas-glycerol conversion rate of 97.2% and an acrolein selectivity of 75.8%. Even after continuous reaction for 16 h, both gas-glycerol conversion and acrolein selectivity remained above 75% and 90%, respectively. This study presents a remarkable advancement in the development of industrial catalysts with outstanding performance in terms of efficiency, stability, and cost-effectiveness. Moreover, this catalyst shows great promise for its utilization in acrolein synthesis via glycerol dehydration.