Study of chromium-doped catalysts in n-butane oxidation to maleic anhydride Original Research Article

In order to investigate the effect of additives on the active sites of VPO catalysts, chromium doped catalysts have been prepared in aqueous medium. The Cr/V atomic ratio was limited to 2.5%. XRD, IR, XPS, isopropyl alcohol decomposition and n-butane oxidation tests were used for a comparative study of the bulk and surface properties of the catalysts. XRD analysis reveals that (VO)2P2O7 and VOPO4 phases are poorly crystallized. The XPS results show a strong surface enrichment of chromium in Cr-doped materials which is deleterious for the production of maleic anhydride (MA). At high conversion, catalyst deactivation occurred by surface coking.