Promotion of dual-reaction pathway in CO2 reduction over Pt0/SrTiO3–δ: Experimental and theoretical verification

The H 2 evolution is generally considered a competing reaction in photocatalytic CO 2 reduction reaction (CO 2 RR) using H 2 O as the proton source. However, the reducing gas H 2 generated from H 2 O splitting can be the proton source in CO 2 RR under the enhanced dynamic role of the thermal effect. The reverse water gas shift (RWGS) reaction, a CO 2 hydrogenation reaction, should occur in photothermal environment owing to thermodynamically and kinetically favorable. Herein, nanostructured metal-semiconductor contact consisting of Pt nanoparticles (NPs) supported on SrTiO 3– δ nanosheets with rich oxygen vacancies (Pt-OVs-STO) was constructed for investigating its feasibility and efficiency in the RWGS reaction under photothermal effect. Our experimental results substantiate that the H 2 generated by H 2 O splitting effectively contributes to the RWGS reaction over Pt-OVs-STO system. The Pt 0 NPs not only efficiently facilitate surface charge transfer, but also lower the energy barrier of the O–H bond breaking, H 2 releasing, and RWGS reaction, thereby showing an outstanding CO 2 RR performance. The strong interaction between the Pt 0 NPs and SrTiO 3– δ has been extensively demonstrated by a series of experimental characterizations and density functional theory calculations. This work elucidates the relation between H 2 evolution and RWGS reaction over Pt 0 /SrTiO 3– δ structure in photothermal catalytic CO 2 RR using H 2 O as the proton source and provides new perspectives for subsequent CO 2 RR.