Acid-redox sites regulation of WVOx on industrial TiO2-Al2O3 for catalytic dehydration and dehydration-oxidation of gas-glycerol

Dehydration and dehydration-oxidation of gas-glycerol to acrolein and acrylic acid presented a promising and alternative approach to the traditional fossil feedstocks. For this, a series of WO₃ and WVO_x supported on TiO₂-Al₂O₃ (TA) catalysts (W/TA, 5WV/TA, 4WV/TA, 3WV/TA, and 4W/V/TA) were synthesized by simple co-impregnation and two-step impregnation methods. The selectivity of acrolein was proportional to the number of weak and medium acid sites of catalysts, following the order of 4WV/TA (78.1 %) > 4W/V/TA (73.0 %) > W/TA (71.7 %) > 5WV/TA (63.1 %) > 3WV/TA (50.5 %) under 25 % O₂ condition. Notably, acrylic acid produced over the 4WV/TA and 4 W/V/TA with selectivity of 18.0 % and 15.5 % under 100 % O₂ condition, respectively, which benefit from the synergistic effect between the acidic sites (WO₃) and redox sites (V₂O₅ and VO₂) and affected by theV⁴⁺/V⁵⁺ ratio. Additionally, both 4WV/TA and 4W/V/TA showed remarkable catalytic stability and reducibility for further industrial improvement.