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为进一步提高V2O5/TiO2催化剂对气相一步催化合成烟酸反应的活性和选择性.通过浸渍法制备一系列掺杂过渡金属铬的V2O5/TiO2催化剂,并对催化剂进行了BET、XRD、H2-TPR、NH3-TPD表征.结果表明,掺杂Cr后催化剂产生了新晶相CrVO4,减小了V2O5晶粒尺寸,并提高了催化剂的酸性,可较大地提高催化剂活性.少量的Cr掺杂促进了V2O5晶格氧的活动性,可同时提高了烟酸的产率和选择性.但过量Cr掺杂,使催化剂表面氧数量增多,导致选择性出现较大的下降.当在Cr掺杂量2%时,260℃的反应温度下烟酸的摩尔产率可达77%.
A series of V2O5 / TiO2 catalysts doped with transition metal chromium were prepared by impregnation method, and the catalysts were characterized by BET, XRD, H2-TPR and V2O5 / TiO2 catalysts to further improve the activity and selectivity of V2O5 / TiO2 catalyst for one- , NH3-TPD.The results show that CrVO4 is produced after the Cr-doped catalyst, which decreases the grain size of V2O5, increases the acidity of the catalyst and greatly increases the catalytic activity. A small amount of Cr doping promotes V2O5 lattice oxygen activity, which can improve the yield and selectivity of nicotinic acid.However, excessive Cr doping, the catalyst surface oxygen increased, leading to a greater selectivity decline when the amount of Cr doping 2 %, The molar yield of nicotinic acid at the reaction temperature of 260 ° C can reach 77%.