RSC Adv. 2023 Jan 6;13(3):1530-1538. doi: 10.1039/d2ra06960a. eCollection 2023 Jan 6.
Based on the precise phase control V species adjustment of vanadium phosphorus oxides (VPOs), a series of metal oxides (Nb2O5, MoO3, WO3, and Bi2O3) were selected as modification agents to further enhance the catalytic activity and retain the excellent durability of VPO-TiO2-based catalysts for the new procedure of producing acrylic acid via acetic acid-formaldehyde condensation. At an elevated liquid hourly space velocity (LHSV), the (AA + MA) selectivity reached 92.3% with a (MA + AA) formation rate of 63.8 μmol-1 gcat -1 min-1 over the Nb-decorated catalyst (catalyst VTi-Nb), and it maintained good durability for up to 100 h. The detailed characterization results of XRD, Raman, XPS, NH3-TPD, CO2-TPD, and H2-TPR, demonstrated that the addition of Nb2O5 could observably enhance the catalytic efficiency of the VPO-TiO2 catalyst. It not only improved the catalyst durability by enhancing prereduction of the V5+ species, but also enhanced the active site density to improve the catalytic activity.