The Effect Of Additives On The Performance Of One-step Preparation Of Vanadium Phosphorus Oxide Catalyst

In this paper,isobutyl alcohol and benzyl alcohol as solvent and reducing agent at the same time,polyphosphoric acid as an alternative phosphorus source,using one-step preparation of vanadium phosphorus oxide(VPO)catalyst precursor VOHPO4·0.5H2O.Characterized by means of the system with a variety of experiments investigated the doping bismuth,niobium additives on one-step preparation of vanadium phosphorus oxide catalyst performance.Doped bismuth additives series of VPO catalyst for the morphology of lamellar crystals were a large number of closely packed into a neat rose bud-like,bud diameter of about 5-7μm,bud film thickness of about 70-80nm.Bi atoms in(VO)2P2O7the V atoms form a solid solution,reduce the content of the catalyst surface V atoms,accelerated by gas adsorption of O2 on the catalyst surface.VPO catalyst was prepared by the high catalytic performance.In the atomic ratio V:P:Bi = 1:1.1:0.01 time(catalyst A3),the molar yield of maleic anhydride catalyst 51.5%,n-butane conversion was 75.3%,69.8%selectivity to maleic anhydride.Nb doped VPO catalyst additive series,under the action of the additives of niobium,VPO catalyst morphology changed after activation of the VPO catalyst both aggregation:one is the large number of closely packed lamellar crystal rose slightly as bud-like,the other is like a small broken crystals scattered distribution.By doping the VPO catalyst performance evaluation of additives and physical and chemical analysis showed that adding vanadium phosphorus oxide catalyst additives are different degrees of increased n-butane conversion and selectivity of the catalyst surface area increases,modulation phase composition of the catalyst to change the morphology of the catalyst.