The capture of CO 2 and its reduction with H 2 to form C1 compounds (i.e., CO 2 capture and reduction; CCR), such as CO and CH 4 , using dual-functional materials (DFMs) has recently attracted attention as a promising process for CO 2 emission reduction and utilization. Although CO is more useful than CH 4 from a chemical synthesis perspective, the development of an effective DFM system to generate CO has been explored much less than that for CH 4 generation. This study successfully developed Na-promoted Pt nanoparticles (NPs) supported on Al 2 O 3 (Pt−Na/Al 2 O 3 ) as an effective DFM for selective CO production by capturing diluted CO 2 from a mixture with O 2 and successive reduction by H 2 . The developed Pt−Na/Al 2 O 3 was applicable for continuous CCR operation using two reactors in parallel and switching feed gases. The CO 2 capture ability and productivity of CO were maintained for at least 100 h. We also elucidated the effect of basic promoters through microscopic and spectroscopic characterizations. The Na-modified Pt nanoparticles (NPs) were formed on Al 2 O 3 , where Na species play two important roles in efficient CO 2 capture and selective CO formation: (i) capturing CO 2 from a mixture with O 2 and (ii) inhibiting the adsorption of generated CO on Pt NPs.