Interfacial Auδ−–OV–Ti Structure Promoted C–H Bond Activation for Selective Oxidation of Fatty Alcohols to Fatty Acids

Oxidation of fatty alcohols to fatty acids is still challenging due to the sluggish activation of the C–H bond over Au supported on reducible oxides with a coordination-saturated structure. Herein, we constructed an efficient interfacial Auδ−–OV–Ti structure by tuning the crystal forms of TiO2. Compared with TiO2-rutile exposed by (110) and (111) crystal facets, TiO2-anatase can exploit the defect (101) crystal facet to obtain rich oxygen vacancies (OV), inducing electron migration from TiO2-anatase support to Au species to form electron-rich Auδ− species. Specifically, the synergistic catalytic effect between the OV–Ti and Auδ− species greatly enhances the adsorption of alcohol and thereby overcomes sluggish activation of the C–H bond caused by the electron pushing effect triggered by long carbon chains. Consequently, the Au/TiO2-anatase catalyst shows excellent isooctyl alcohol conversion (69.5%) and isocaprylic acid selectivity (67.9%) under base-free conditions. The catalytic system is further extended to the oxidation of other fatty alcohols to fatty acids with excellent catalytic performance.