Emission standards for diesel particulates (soot) and NOx from diesel engine exhaust have been introduced worldwide and are becoming more stringent due to their adverse effects on human health and the environment. With respect to the removal of diesel particulates, the application of diesel particulate filters (DPFs) could provide more than a 90% reduction in mass emissions. However, these filters are required to be regenerated because the trapped soot can lead to elevated exhaust line pressure, leading to decreased engine efficiency. Among the regeneration strategies, catalytic regeneration of PDFs by low temperature soot oxidation catalysts is the most promising. This dissertation deals with catalysis as a means to decrease particulate emissions from diesel exhaust gases. In view of economical and environmental concerns, platinum-free soot oxidation catalysts have been gaining more attention. In particular, this thesis will focus on the application of K containing catalysts for soot oxidation at low temperatures. However, most of the studied K containing catalysts are subjected to deactivation after a short period of reaction due to the loss of potassium during soot oxidation. The problem can be resolved by either stabilizing K moderately in the lattice or replenishing the loss of K from a K source. Based on the initial work on K2O-2SiO2 disilicate catalysts, the concept of an amorphous silicate catalyst will be developed to achieve high K stability catalyst. In particular, the impacts of Ca and Al substitutions on the K stability in potassium disilicate glass network are discussed. After optimizing the composition of K stability silicate based catalysts, a detailed stability study on an optimized K-Ca-Si-O composition is investigated and discussed. The mechanism for this kind of compound on soot oxidation is also proposed, which is thought based on the combination of oxygen transfer mechanism and spillover mechanism. In the scope of the synthesis of silicate catalyst, a sol-gel process is developed to make a multi-component silicate compound. This aqueous based sol-gel process is very suitable to coat the DPFs due to the complex shapes and porous nature of the filters. Then the equivalent optimized K-Ca-Si-O silicate catalyst is applied on both ceramic DPFs and metallic DPFs via sol-gel process. The stability study and kinetics study are sequentially carried out to investigate the catalytic reactions. The feasibility of these mentioned catalytic options is discussed as well. In addition, the nature of soot and contact condition between soot and catalysts play important roles in catalytic soot oxidation. The characterization and kinetic analysis of a model soot produced from flame deposit is also studied and discussed. The purpose is to establish a reliable and suitable laboratory approach for catalytic soot oxidation study by simulating the realistic contact condition.