Anchoring Monolayer TiO x Nanosheets on Gold Nanoparticles Enhances Catalytic Activity for CO Oxidation Depending on the Type of Support

Catalytic performance of supported gold catalysts is governed by the contact structure between Au nanoparticles (NPs) and reducible metal oxides. In this study, we constructed an Au–TiO x interface by decorating supported Au NPs with monolayer titania nanosheets (TNS). We report a support‐dependent formation of the interface between Au and TiO x thin overlayer. For Au/SiO 2 , TNS adsorption followed by calcination significantly enhanced CO oxidation activity. In contrast, for Au/CeO 2 , TNS adsorption without calcination markedly improved the activity. Spectroscopic analyses revealed that cationic Au and Ti 3+ species increased after TNS adsorption for Au/CeO 2 and the subsequent calcination for Au/SiO 2 , respectively, suggesting the formation of Au–TiO x interface. X‐ray photoelectron spectroscopy (XPS) showed that TNS adsorption on CeO 2 induced a slight increase in Ce 3+ species, consistent with Ce–O–Ti anchoring via interaction between surface Ti–OH and Lewis acidic Ce 4+ sites. The surface reaction between TNS and redox‐active CeO 2 gives Au–TiO x contact structures, whereas nonreducible SiO 2 requires calcination. Moreover, the TiO x overlayer derived from TNS was more oxygen‐deficient than that obtained by impregnation of Ti species. This work demonstrates that the use of monolayer TNS is advantageous for the formation of active Au–TiO x interface and rich oxygen vacancies.