Recent advances in three way catalysts of natural gas vehicles

Natural gas vehicles (NGVs), as alternatives to gasoline and diesel vehicles, have been rapidly and widely promoted in the past 20 years. The three-way catalyst (TWC) technology is one of the dominant technologies for gaseous emission control of NGVs. However, it is still a great challenge to purify the exhaust gas of NGVs to meet increasingly strict emission limits, particularly for CH4 and NOx. This review is focused on the recent research advances in TWCs for NGVs, including the technical fundamentals, classic components (active phases, supports, and promoters), novel preparations of catalysts, resistance to thermal and chemical aging, current challenges and future perspectives. Particular attention is given to Pd-based catalysts as typical commercial TWCs, and potential alternatives which have competitive three-way catalytic performance are also highlighted.