Enhancing catalytic performance of phosphorus-modified ceria supported VPO catalysts for n-butane oxidation

Abstract Vanadium phosphorus oxide (VPO) catalysts supported on CeO 2 and P-modified CeO 2 (P-CeO 2 ) have been firstly synthesized for selective oxidation of n -butane to maleic anhydride (MA). The catalysts supported on P-CeO 2 showed higher catalytic performance, especially higher MA selectivity than catalysts on pure ceria, and their specific activities (normalized to per unit mass of VPO loading) were also superior to that of bulk VPO. TG, TEM, XRD, Raman, H 2 -TPR and XPS results revealed that the structure and property of VPO are largely affected by the support. The loaded VPO existed almost wholly as VOPO 4 phases on pure ceria, while mainly in the form of (VO) 2 P 2 O 7 with small amount of VOPO 4 phases on phosphorus-modified ceria. Both VPO/P-CeO 2 and bulk VPO catalysts have the similar VPO phase structure, but the former showed the enhanced reducibility of V 4+ phase. These differences in structure and properties of the catalysts were discussed and related to their different catalytic performances.