With the increase in worldwide automobile usage and the tightening of associated emissions legislation, the total demand of PGMs for use in automotive emission control catalysts is growing. Reducing the amount of required PGM in automotive catalysts as well as maintaining or improving the associated catalytic performance is an area of significant focus. This work presents a comparative study of the catalytic activity of Pd-only, Pd/Rh and Rh-only catalyst systems with respect to CO, HC and NO_x conversion. The Rh-only catalyst has been shown to have the potential to improve CO and NO_x conversions when functioning as a downstream catalyst compared with a Pd/Rh catalyst as well as reducing the usage of precious metals. In addition the formation of the three way catalysis by-products N₂O and NH₃ in different catalyst systems was investigated. The temperature of N₂O and NH₃ formation was shown to correlate with NO_x light off temperatures and to vary depending upon the catalyst system employed and ageing conditions. The Rh-only catalyst was shown to generate the highest amount of N₂O and the Pd-only catalyst the highest amount of NH₃.

随着全球汽车使用量的增加以及相关排放法规的严格，用于汽车排放控制催化剂的PGM的总需求正在增长。减少汽车催化剂中所需PGM的量以及维持或改善相关的催化性能是一个重点关注的领域。这项工作提出仅含Pd的，将Pd / Rh和Rh的仅催化剂体系相对于CO，HC和NO的催化活性的比较研究_X转换。与Pd / Rh催化剂相比，仅Rh催化剂在用作下游催化剂​​时具有提高CO和NO _x转化率的潜力，并能减少贵金属的使用。另外形成三元催化副产物N研究了不同催化剂体系中的₂ O和NH ₃。N ₂ O和NH ₃形成的温度显示与NO _x起燃温度相关，并且取决于所使用的催化剂体系和老化条件而变化。已显示仅Rh的催化剂产生最高量的N ₂ O，而仅Pd的催化剂产生最高量的NH ₃。