Evolution of surface of Pd-Rh bimetallic nanocubes and its correlation with CO oxidation

Typically, varying pretreatment conditions probably results in the different catalytic performances for the bimetallic catalysts, and this originates from the surface evolution of catalysts during catalytic process. Hence, it is crucial to correlate surface chemistry (e.g., composition, chemical valence, etc.) of bimetallic nanocatalysts with their corresponding performances upon different pretreatments for the fundamental understanding of catalysis. Herein, compositionvaried (100) facet terminated Pd-Rh nanocubes (NCs) with the similar shape and sizes were prepared by a facile one-pot hydrothermal method to exclude the possible size and shape effect. Surface composition and valence state of these Pd0.8 Rh0.2, Pd0.6Rh0.4, and Pd0.2Rh0.8 NCs were tracked under different reaction conditions and during catalysis using a homebuilt ambient pressure X-ray photoelectron spectrometer (APXPS). The correlation of active surface of Pd-Rh NCs and their corresponding catalytic performance was established.