New Design and Construction of Abundant Active Surface Interfacial Copper Entities in CuxCe1-xO2 Nanorod Catalysts for CO-PROX

Composite CuxCe1-xO2 nanorod catalysts with abundant Cu-Ce interface for CO preferential oxidation are synthesized via a one-pot co-precipitation method at ambient temperature, and then copper species are induced to migrate and enrich on the surface and subsurface of CuxCe1-xO2 by thermal treatment. The best low temperature catalytic activity (T-50% = 77 degrees C) and widest operation window (95-150 degrees C) are achieved by thermal treatment at 700 degrees C. With the thermal treatment temperature increasing from 200 to 700 degrees C, first Cu-Ce solid solution forms (at 400 degrees C), then Cu species migrate to the surface and subsurface of CuxCe1-xO2 nanorods, forming a lattice relaxation layer containing abundant highly dispersed CuOx species and strongly bonded Cu-[O-x]-Ce species, whose thickness is gradually reduced but the tightness is increased, thus strengthening the Cu-Ce interaction. The amount changing and redox process of the active copper entities respectively involving low and high temperature CO-PROX reaction are in-depth clarified.