Preparation of Highly Active Ceramics Catalysts by Chemical Vapor Deposition for Catalytic Combustion

在催化燃烧过程中，需要开发高活性和热稳定的陶瓷催化剂。本研究主要采用化学气相沉积（CVD）和化学液相沉积（CLD）两种方法制备负载型混合氧化物催化剂。结果表明：(1)化学液相沉积法制备高度分散的LaCoO_3/ZrO_2 （CLD）用La和Co两种醋酸盐的混合水溶液浸渍ZrO_2，制备了LaCoO_3高度分散的ZrO_2。红外光谱（IR）、x射线衍射（XRD）和透射电镜（TEM）证实了该材料的高分散性。该催化剂对丙烷的完全氧化表现出很高的催化活性。(2)氧化钒：用CVD法制备的氧化钒薄膜催化剂，用XPS和XRD证实了CVD法制备的VO (c_2H_5)_3在SiO_2上形成了高度分散的氧化钒覆盖层。此外，EXAFS和XANES分析显示V_2O_5以薄膜形式存在。该催化剂比浸渍法制备的V_2O_5催化剂活性高。(3)低温氧等离子体制备分散在ZrO_2上的高活性CoO_X，将分散在ZrO_2上的OCOCH_3 _2用ar等离子体中活化的氧处理。红外光谱分析证实，经此处理后，Co (OCOCH_3)_2全部转化为CoO_X。该催化剂对丙烷的完全氧化活性远高于Pt/Al_2O_3和La_<0.8>Sr_<0.2>coO_3这两种优良的氧化催化剂。结果表明，CLD、CVD和利用氧等离子体是制备载体氧化薄膜的较好方法，对催化燃烧具有较高的催化性能。

In catalytic combustion processes, development of highly active and thermally stable ceramics catalyst is desired. In the present study, the preparations of supported mixed oxide catalysts mainly by Chemical Vapor Deposition (CVD) and Chemical Liquid Deposition (CLD) methods were tried. The results are summarized as follows :(1) Highly Dispersed LaCoO_3/ZrO_2 prepared by Chemical Liquid Deposition (CLD)LaCoO_3 highly dispersed ZrO_2 was prepared by impregnating ZrO_2 with aqueous solutions of the mixtures of La and Co acetates. The high dispersion was confirmed by IR, XRD, and TEM. This catalyst showed a very high catalytic activity for complete oxidation of propane.(2) Vanadium Oxide This Film Catalysts Prepared by CVDHighly dispersed vanadium oxide overlayers were formed on SiO_2 by CVD of VO (c_2H_5)_3 as was confirmed by XPS and XRD. Furthermore, EXAFS and XANES analyses revealed that the V_2O_5 were present as thin films. This catalyst was much more active than V_2O_5 prepared by an impregnation method for oxidative dehydrogenation of a alcohol.(3) Highly Active CoO_X Dispersed on ZrO_2 Prepared by Low-Temperture Oxygen plasmaCo (OCOCH_3)_2 dispersed on ZrO_2 was treated with oxygen which was activated in Ar-plasma.It was confirmed by infrared spectroscopy that all Co (OCOCH_3)_2 were changed to CoO_X by this treatment. This catalyst showed activities for the complete oxidation of propane much greater than Pt/Al_2O_3 and La_<0.8>Sr_<0.2>coO_3 which were reported to be excellent oxidation catalysts.These results demonstrate that CLD, CVD and utilization of oxygen-plasma were superior methods to prepare oxide-thin films on supports, which posses high catalytic performance for the catalytic combustion.