Role of Ba in an Al 2 O 3 ‐Supported Pd‐based Catalyst under Practical Three‐Way Catalysis Conditions

Reducing everything: Roles of Ba in the Pd-based three-way catalysts were investigated by practical performance tests using a commercial vehicle and in situ/operando IR spectroscopic methods. Ba was found to reduce all the emissions (NOx, CO, and non-methane hydrocarbons) in the exhaust gas. The IR studies using powder model catalysts revealed that the efficient formation of surface nitrate species as intermediates and their subsequent reaction with reductant gases such as CO and C3H6 would be a key role of Ba to reduce emissions.