OMS-2负载Pt催化剂的制备及其催化氧化性能研究

采用前掺杂法、沉积-沉淀法和浸渍法制备了氧化锰八面体分子筛(OMS-2)负载Pt催化剂(Pt/OMS-2),对所制催化剂进行了结构和织构表征。并研究了不同制备方法和沉积-沉淀法中不同制备(Pt负载量和溶液的pH值)对Pt/OMS-2催化氧化CO性能的影响。结果表明,沉积-沉淀法制备的Pt/OMS-2-DP催化剂活性最好(T100=100℃)。这与Pt/OMS-2-DP催化剂中Pt颗粒大小及OMS-2载体与Pt之间存在强相互作用有关。Pt负载量明显影响Pt/OMS-2-DP催化剂的催化活性,3Pt/OMS-2-DP催化剂(Pt=3.0 wt%)催化活性最高,这是由于适当Pt负载量,Pt颗粒较小,并与载体OMS-2的相互作用较强,能较好地活化OMS-2晶格氧。pH值对Pt/OMS-2-DP催化剂催化性能影响较大,这与OMS-2的等电点和Pt在不同溶液中存在不同Pt配位体形式有关。

Pt-doped OMS-2 Catalysts: Preparation and Properties of Catalytic Oxidation

Pt/OMS-2 catalysts were prepared by pre-incorporation(PI),typical wet impregnation(IM) and depositionprecipitation(DP) methods.Influences of preparation methods,Pt loading and pH values of preparation solution on the catalytic activity of CO oxidation were studied.The samples were characterized by X-ray diffraction(XRD) and N2adsorption/desorption.Results showed that as compared with typical wet impregnation method and pre-incorporation methods,Pt/OMS-2-DP prepared from deposition-precipitation method revealed higher activity,due to the smaller particle size and stronger interaction between Pt and OMS-2.The catalyst activity for catalytic oxidation of CO increased with an increases of Pt loading and passed through a maximum in activity at 3.0wt% Pt.Pt/OMS-2-DP catalyst,prepared at pH 8 solution,showed a significant improvement of catalytic activity,this may be due to interaction between OMS and Pt,which keep smaller particle size over OMS-2 support.