Nowadays, the Three-Way Catalyst (TWC) is the standard solution employed in the automotive industry to cut down CO, HC, and NOx tailpipe emissions of vehicles equipped with gasoline engines. The current trend towards more stringent regulations and severe testing procedures is pushing the design of modern propulsion and after-treatment systems to higher levels of complexity. This is especially true in the case of high-performance applications, for which compliance with the requirements of type approval is a serious task to accomplish. Therefore, it is necessary to develop numerical models embedding properly defined kinetic schemes, that can predict, robustly and accurately, the catalyst performances under various operating conditions.