NOx Reduction at Near Ambient Temperatures and Under Lean‐Burn Conditions on Modified Pd Surfaces

Palladium surfaces that are modified with O atoms in the subsurface broaden the NO reduction temperature regime up to 325 K with O2‐rich NO+H2+O2 compositions. Compared to virgin Pd surfaces, up to 150 % higher deNOx catalytic activity was observed with modified Pd surfaces at the reaction maximum. Molecular beam instrument and ambient‐pressure photoelectron spectroscopy were employed to follow the kinetic and surface changes. These results open up a possibility to realize the cold‐start reduction of NOx (deNOx). DeNOx activity reported in the literature with supported Pd catalysts after a simple calcination in air compares well with our present observations. Surface modification is likely to demonstrate a high potential for other catalytic reactions at relatively low temperatures.