NO Reduction on Cu-Based Model Catalysts Studied by in-situ IRAS

Comprehensive Summary Cu-based catalyst has been widely used for catalytic reduction of NO. Well-defined TiOx/Cu(110) films were prepared and investigated by in situ reflection absorption infrared spectroscopy (IRAS), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). A complex surface structure of Cu+(-O-Ti-)-O-Cu delta+/Cu(110) was proposed, in which the topmost surface Cu+ is highly dispersed, isolated and fixed by the TiOx layer. Such a 'single atom'-like surface site appears a very narrow nu(CO) peak at 2130 cm(-1), and is more stable upon both CO reduction and vacuum annealing than the Cu2O/Cu(110). Such isolated Cu+(-O-Ti-) site on TiOx/Cu(110) is also fairly stable in NO+CO reaction, but the overall catalytic activity is slightly lower than that on the Cu(110) surface, indicating that the single-atom Cu+(-O-Ti-) site is less efficient for NO+CO reaction at the examined conditions. The study provides useful information for the design and application of single-atom catalysts and understanding the nature of catalytically active centers.