Tandem Base-Metal Oxide Catalyst: Superior NO Reduction Performance to the Rh Catalyst in NO–C 3 H 6 –CO–O 2

We developed a high-performance PGM-free three-way catalyst based on a new strategy: a combination of two base-metal oxide catalysts with tandem configuration for hydrocarbon preferential oxidation (PROX) in upstream of exhausted gas and efficient purification of NO by CO in the downstream flow. The effectiveness of the tandem concept is verified by a combination of ZnCr 2 O 4 for C 3 H 6 –PROX and CuCo 2 O 4 for NO–CO–O 2 reaction. The combination achieved a comparable performance to a Rh/ZrO 2 catalyst, in terms of NO conversion (66.9%) and a superior performance regarding N 2 yield (59.9%) and N 2 selectivity (89.8%) at 300 °C.