掺Ni钒磷氧化物催化剂的合成和表征

以VOPO4.2H2O为原料制备了钒磷氧化物催化剂,考察了镍掺杂(1%,2%和5%)对该催化剂的影响.低掺杂量的Ni明显提高了活性晶格氧物种O-的数量,降低了V5 和V4 相的还原峰温.粉末X射线衍射、程序升温还原和化学分析结果表明,高掺杂量的Ni促使V5 物相生成并抑制V4 物相出现.高含量与V5 相关的氧物种会降低正丁烷的转化率,但会提高马来酸酐的选择性.

Synthesis and Characterization of Ni-Doped Vanadium Phosphorus Oxide Catalysts

The effect of Ni doping (1%, 2%, and 5%) on vanadium phosphate catalysts prepared via VOPO₄·2H₂O was described and discussed. At low levels, the Ni dopant significantly enhanced the amount of the active lattice oxygen species O⁻ and lowered the reduction peak temperature corresponding to the reduction of V⁵⁺ and V⁴⁺ phases. A combination of powder X-ray diffraction, temperature-programmed reduction, and chemical analysis data shows that at higher levels, Ni doping induced the formation of the V⁵⁺ phase and suppressed the presence of the V⁴⁺ phase. Previous studies have indicated that a large amount of oxygen species associated with V⁵⁺ inhibit the n-butane conversion but promote the selectivity for maleic anhydride.