调控制备pH值对铁钼催化剂结构及性能的影响

Effect of pH value on the structure and properties of iron-molybdenum catalysts during preparation

通过调控共沉淀中钼酸铵溶液的酸度制备了系列铁钼催化剂,采用N_2吸附-脱附、Raman、XRD、SEM、H2-TPR等方法对催化剂的结构进行了表征,并考察了不同酸度条件下制备的铁钼催化剂的甲醇氧化制甲醛催化活性。结果表明,钼酸铵溶液酸度影响催化剂的粒径、形貌及表层铁、钼物种的分布与富集。恰当的钼酸铵溶液酸度范围,优化了催化剂表层MoO_3和Fe_2(MoO_4)_3物种的比例,改善了催化剂的催化氧化性能,有利于甲醇氧化制甲醛收率和选择性的提高。

A series of iron-molybdenum catalysts were prepared by controlling the acidity of ammonium molybdate solution in coprecipitation.The structure of the catalysts was characterized by N2 adsorption-desorption,Raman,XRD,SEM and H2-TPR.The Fe-Mo catalysts prepared with different pH values were investigated for their performance in methanol oxidation to formaldehyde reaction.The results showed that the acidity of ammonium molybdate solution affects the particle size,morphology,distribution and enrichment of iron and molybdenum species on the surface of the catalyst.Appropriate acidity of ammonium molybdate solution can optimize the ratio of MoO3 and Fe2(MoO4)species on the catalyst surface,and improves the catalytic oxidation performance,which is conducive to the improvement of yield and selectivity of formaldehyde.