Reduction-tolerant SnO2 assisted by surface hydroxyls for selective CO2 electroreduction to formate over wide potential range. (April 2023)

• Record Type: Journal Article
• Authors: Liu, Zhipeng; Chen, Junjie; Guo, Hongshan; Huang, Xiaoxi
• Is Part Of: Nano energy. Volume 108(2023)
• Publication Date: 2023-04
• Subjects: CO2 reduction reaction -- Tin dioxide -- Surface hydroxyls -- Formate -- Electrocatalyst; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2023.108193
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Tin oxide based materials have been identified as active catalysts for electrochemical CO2 -to-formate conversion. However, the oxide is unstable and can easily reconstruct via self-reduction under CO2 reduction reaction (CO2 RR) condition, resulting in undesired elevated hydrogen evolution reactivity. In this work, a stable tin dioxide (SnO2 -1) electrocatalyst with abundant surface hydroxyls was synthesized via sodium cation assisted calcination method. The resulting electrocatalyst exhibits higher selectivity toward formate in a wide potential window compared with the one with very little hydroxyl groups. In addition, we demonstrate that SnO2 -1 can operate at high current density of 200 mA·cm −2 for at least 6 h while maintaining FEformate over 80%. Assisted with density functional theory (DFT) calculations, we propose that the presence of surface hydroxyls factors significantly into the overall performance of CO2 RR, including optimization of the formation energy of key intermediate *OCHO and help SnO2 to preserve partially reduced active surface. Graphical Abstract: A SnO2 nanomaterial with surface hydroxyls is synthesized with outstanding selectivity for electrochemical CO2 -to-formate conversion in a wide potential range. The hydroxyls can help to improve the stability of electrocatalyst under cathodic condition. Additionally, the partially reduced surface as well as the terminal hydroxyl can promote the activity by optimizing the binding strength of key intermediate. These results are crucial for the design of efficient electrocatalyst for CO2 utilization. ga1 Highlights: SnO2 with surface OHs are synthesized at high temperature. Surface OHs can help to improve the stability of SnO2 under cathodic potential. Terminal OHs are crucial to optimize the binding energy of OCHO for enhanced activity. High selectivity toward formate is achieved in wide potential window.