Nearly 100% selectivity of photothermal CO2 reduction into CH4 achieved by Pt/Sr2Nb2O7 heterojunction

Developing efficient and highly selective photocatalytic CO 2 reduction catalysts remains one of the most significant challenges in achieving carbon neutrality . Herein, the efficient conversion of CO 2 to CH 4 with selectivity close to 100% was achieved by loading uniformly dispersed Pt nanoparticles on the surface of Sr 2 Nb 2 O 7 nanosheets ; the optimal CH 4 yield was as high as 15.65 μmol/g/h. Various characterizations demonstrate that Pt nanoparticles have a significant photothermal effect that can increase the catalyst surface temperature, and improve the performance and electron transport rate of the catalyst. Additionally, Pt nanoparticles and Sr 2 Nb 2 O 7 nanosheets form heterojunctions , which facilitate the separation of photogenerated carriers and aggregation of photogenerated electrons on the Pt nanoparticles. Pt nanoparticles become new reactive sites that have a strong adsorption impact on the key intermediate ∗CO and reduce the reaction energy barrier of ∗CHO generation. The results revealed that the synergy between electron accumulation, strong adsorption of ∗CO, and reduction of the reaction potential of ∗CHO are the reasons for the efficient and selective conversion of CO 2 to CH 4 . This work provides novel insights into the role of metal-based cocatalysts in selective CO 2 photoconversion and new ideas for designing efficient CO 2 conversion systems.