Preparation And Properties Of Palladium Catalysts For Methane Combustion

The emission of lean methane with lower utilization from coal mine is very large every year, which causes a serious resource waste. The greenhouse effect of methane is twenty-one times more than that of CO2, which results in the increase of greenhouse gas and depletion of ozone layer. Consequently, efficient utilization of methane is of great significance for energy utilization, environmental protection and coal mine safety. Because of the high initial temperature of methane oxidation, N2 in the atmosphere can be oxidized into NOx, which leads to secondary pollution. Catalytic combustion technology can reduce the initial temperature of methane, which achieves methane oxidation at low temperature. Preparation of the catalysts with perfect thermal stability at higher temperature and high catalytic activity at lower temperature is very important for methane catalytic combustion.The kinds of catalysts and the different factors are reviewed on Pd catalysts for methane combustion in this paper, and studied the preparation and its performances of Pd catalysts.A series of Pd noble metal catalysts were prepared by five different precipitation methods. The reactivity of catalytic combustion of methane over catalyst was tested in a fixed-bed microreactor, and the thermal stability was studied and compared. Surface area and pore size distribution were both tested. The size of the particle size, the size of grain size of sintered body, and the compactness of structure were tested by using SEM. The surface properties and reactions of catalysts were characterized by TPD test. The dispersion degrees of Pd catalysts were tested by H2-O2 titration. The reduction performance of the catalyst was explored by TPR at different heating rate, and the reduction activation(ER) energy was calculated, so that the relationship between the activation energy and the catalytic activity of catalyst was evaluated.