Tuning Lewis acid/base on the TiO2-supported Pd-CoOx interfaces to control the CO2 selective hydrogenation.

• Pd-CoO∙TiO 2 /TiO 2 and Pd-CoO x /TiO 2 represent high catalytic activity and selectivity in CO 2 transformations. • CO is a good prober toward Lewis acidic centers for the reaction intermediates of methoxy species. • Lewis acidity and alkalinity are readily controllable on the catalysts surfaces. • High catalytic performances are derived from the cooperation of Lewis acid/base on the interfaces. • The studies provide an alternative solution to relate the catalytic activity with the strengths of Lewis acids and bases. A highly attractive aim is to turn CO 2 into useful chemicals selectively and efficiently, but it still retains great challenging to understand the relations between catalytic performances and interface properties. Here, we report an alternative solution to relate the catalytic activity with the strengths of Lewis acids and bases on the Pd-CoO x interfaces. CoO∙TiO 2 /TiO 2 and CoO x /TiO 2 possess the wide spectrum of Lewis acid/base centres, and give the low selectivity and conversion. The introduction of Pd can focus them on the intrinsic centres, and makes Pd-CoO∙TiO 2 /TiO 2 and Pd-CoO x /TiO 2 represent the ideal catalysis. With temperature-programmed desorptions of CO 2 , CO and NH 3 , it is evidenced that the catalytic hydrogenations of CO 2 to CO, CH 4 and CH 3 OH depend on the cooperation of the Lewis acidic/alkaline centres on the interfaces. The studies provide guidelines for rational design and synthesis of heterogeneous catalysts including but not limited to CO 2 hydrogenation. [Display omitted] [ABSTRACT FROM AUTHOR]