The Influences Of Cordierite Surface Modification In PD-Based Monolithic Catalysts’ Structures And Properties

The best way to utilize coal mine ventilation air methane is catalytic combustion, and the properties of catalysts are the key points in methane oxidation.In order to research the catalysts of ventilation air methane combustion, the Pd/γ-Al2O3/cordierite catalysts were made, and were characterized by XRD, SEM, XPS and BET. The catalytic activities were evaluated in different conditions for methane oxidation.Firstly, the influence of oxalic acid concentration and processing time in catalytic activities were investigated, respectively. The results showed that the catalysts which cordierites were treated using20%oxalic acid for1hour had the best catalytic activity.Secondly, different alumina sols were prepared using aluminum sulfate, aluminum nitrate, aluminum chloride and pseudo-boehmite, and were applied to the washcoat of Pd/γ-Al2P3/cordierite catalysts. The influences of different aluminium sources in catalytic activities were investigated, and the results showed the catalysts using aluminum sulfate had the perfect catalytic performance, and because of Pd(OH)2, aluminum nitrate catalyst had the worst catalytic activity.Thirdly, the influence of γ-Al2O3contents and additive in catalyst performance were investigated. The results showed the perfect γ-Al2O3contents were7%and10%for inorganic aluminum salt and pseudo-boehmite catalysts, relatively. Adding PEG-4000can improve the catalytic activity of inorganic aluminum salt catalysts, and the catalytic activity of pseudo-boehmite catalysts reach a top when the urea contents was m(pseudo-boehmite):m(urea)=3:1.Lastly, the impact of space velocity in catalytic activity was studied, and the stability of pseudo-boehmite catalyst was evaluated. The results showed the catalytic activity decreased with the increase of space velocity. The stability of pseudo-boehmite catalyst was very good, and the CH4conversion can be improved by high temperature activation.