VPO polymer β NH 4(VO 2)(HPO 4) was synthesized from the mixture of NH 4VO 3 and NH 4H 2PO 4 in aqueous acidic solution. This hydrogenphosphate vanadate crystallizes in the orthorhombic space group Pbca with a=0.680 ...VPO polymer β NH 4(VO 2)(HPO 4) was synthesized from the mixture of NH 4VO 3 and NH 4H 2PO 4 in aqueous acidic solution. This hydrogenphosphate vanadate crystallizes in the orthorhombic space group Pbca with a=0.680 60(8) nm, b=0.925 70(5) nm, c=1.773 70(2) nm, V=1.117 5(3) nm 3, Z=8, D c=1.743 g·cm -3 , μ=88.54 cm -1 and R=0.051. The structure is built up from VO 5 square pyramid linked by trans vertices through the bridged oxygen atom to form an one dimensional isolated chain of {VO 2HPO 4} n- nunning along the a axis.展开更多
Phase composition, surface characterization and catalytic performance of VPO and thulium doped VPO catalysts were investigated by means of NH3-TPD, XPS,XRD and IR. Experimental results showed that when Tm/V (atomic ra...Phase composition, surface characterization and catalytic performance of VPO and thulium doped VPO catalysts were investigated by means of NH3-TPD, XPS,XRD and IR. Experimental results showed that when Tm/V (atomic ratio) ＜0.10, both Bronsted and Lewis acidities on the surface of VPO catalysts with the addition of thulium were stronger than those of VPO catalyst, the doped catalyst accelerated the dehydrogena tion step of the oxidation reaction of n-butane. Conversion of n-butane and selectivity to maleic anhydride were enhanced. While Tm/V■0.10, the surface acidity of the catalysts was decreased and the activity of catalysts was dropped.展开更多
文摘VPO polymer β NH 4(VO 2)(HPO 4) was synthesized from the mixture of NH 4VO 3 and NH 4H 2PO 4 in aqueous acidic solution. This hydrogenphosphate vanadate crystallizes in the orthorhombic space group Pbca with a=0.680 60(8) nm, b=0.925 70(5) nm, c=1.773 70(2) nm, V=1.117 5(3) nm 3, Z=8, D c=1.743 g·cm -3 , μ=88.54 cm -1 and R=0.051. The structure is built up from VO 5 square pyramid linked by trans vertices through the bridged oxygen atom to form an one dimensional isolated chain of {VO 2HPO 4} n- nunning along the a axis.
文摘Phase composition, surface characterization and catalytic performance of VPO and thulium doped VPO catalysts were investigated by means of NH3-TPD, XPS,XRD and IR. Experimental results showed that when Tm/V (atomic ratio) ＜0.10, both Bronsted and Lewis acidities on the surface of VPO catalysts with the addition of thulium were stronger than those of VPO catalyst, the doped catalyst accelerated the dehydrogena tion step of the oxidation reaction of n-butane. Conversion of n-butane and selectivity to maleic anhydride were enhanced. While Tm/V■0.10, the surface acidity of the catalysts was decreased and the activity of catalysts was dropped.
