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

• Published in: Materials today. Nano Vol. 22; p. 100327
• Main Authors: Pan, L.K., Qi, J.C., Mei, H., Yao, L., Liu, H.X., Zhou, S.X., Zhu, G.Q., Wang, J.J., Cheng, L.F., Zhang, L.T.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2023
• Subjects: Carrier separation; CH4 selectivity; Electron aggregation; Photothermal effect; S-scheme; CH4 selectivity; Photothermal effect; Carrier separation; S-scheme; Electron aggregation
• ISSN: 2588-8420; 2588-8420
• DOI: 10.1016/j.mtnano.2023.100327

Developing efficient and highly selective photocatalytic CO2 reduction catalysts remains one of the most significant challenges in achieving carbon neutrality. Herein, the efficient conversion of CO2 to CH4 with selectivity close to 100% was achieved by loading uniformly dispersed Pt nanoparticles on the surface of Sr2Nb2O7 nanosheets; the optimal CH4 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 Sr2Nb2O7 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 CO2 to CH4. This work provides novel insights into the role of metal-based cocatalysts in selective CO2 photoconversion and new ideas for designing efficient CO2 conversion systems. [Display omitted] •Pt/Sr2Nb2O7 heterojunction with photothermal effect achieved nearly 100% CO2 to CH4.•Pt loading changed the ∗CO adsorption and charge distribution on the Sr2Nb2O7 surface.•It was the synergistic effect of Pt and Sr2Nb2O7 rather than alone Pt that achieved the high CH4 selectivity.