Design of less than 1 nm Scale Spaces on SnO2 Nanoparticles for High-Performance Electrochemical CO2 Reduction

Electrochemical carbon dioxide reduction reaction (CO2RR) is a promising approach to mitigate CO2 concentration and generate carbon feedstock. Recently, the (sub-)nanometer design of catalyst structures has been revealed as an efficient means to control the reaction process through the local reaction environment. Herein, the synthesis of a novel tin oxide (SnOx) nanoparticle (NP) catalyst with highly controlled sub-nanoscale interplanar gaps of widths <1 nm (SnOx NP-s) is reported via the lithium electrochemical tuning (LiET) method. Transmission electron microscopy (TEM) and 3D-tomo-scanning TEM (STEM) analysis confirm the presence of a distinct segmentation pattern and the newly engineered interparticle confined space in the SnOx NP-s. The catalyst exhibits a significant increase in CO2RR versus hydrogen evolution selectivity by a factor of approximate to 5 with 20% higher formate selectivity relative to pristine SnO2 NPs at -1.2 V-RHE. Density functional theory calculations and cation-size-dependent experiments indicate that this is attributable to a gap-stabilization of the rate-limiting *OCHO and *COOH intermediates, the formation of which is driven by the interfacial electric field. Moreover, the SnOx NP-s exhibits stable performance during CO2RR over 50 h. These results highlight the potential of controlled atomic spaces in directing electrochemical reaction selectivity and the design of highly optimized catalytic materials.

Automated summary

This study presents a novel tin oxide nanoparticle catalyst with highly controlled sub-nanoscale interplanar gaps synthesized via the lithium electrochemical tuning method. The catalyst shows significant enhancement in CO2RR selectivity and stability over 50 hours, indicating the potential of controlled atomic spaces in directing electrochemical reaction selectivity and the design of highly optimized catalytic materials.