Single Atom Catalyst Transforms CO2 Into Ethanol

Tandem single atom electrocatalyst realizes reduction of CO2 to ethanol. Credit: DICP

A recent breakthrough in CO₂ reduction research involves a newly developed Sn-based catalyst that efficiently produces ethanol, representing a significant step forward in renewable energy technology.

The electrochemical CO₂ reduction reaction (CO₂RR) into carbon-based fuels provides a promising strategy to mitigate CO₂ emission and promotes the utilization of renewable energy.

Challenges in CO₂ Reduction

C_n (n≥2) liquid products are desirable because of their high energy densities and ease of storage. However, manipulation of C-C coupling pathway remains a challenge due to the limited mechanistic understanding.

Breakthrough Research

Recently, a research group led by Profs. Tao Zhang and Yanqiang Huang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has developed a Sn-based tandem electrocatalyst (SnS₂@Sn₁-O3G), which could reproducibly yield ethanol with a Faradaic efficiency of up to 82.5% at -0.9 V_RHE and a geometric current density of 17.8 mA/cm².

The study was published recently in the scientific journal Nature Energy.

Catalyst Development

The researchers fabricated the SnS₂@Sn₁-O3G through a solvothermal reaction of SnBr₂ and thiourea on a three-dimensional carbon foam. The electrocatalyst comprised SnS₂ nanosheets and atomically dispersed Sn atoms (Sn₁-O3G).

Mechanistic Insights

A mechanistic study showed that this Sn₁-O3G could respectively adsorb *CHO and *CO(OH) intermediates, therefore promoting C-C bond formation through an unprecedented formyl-bicarbonate coupling pathway.

Moreover, by using isotopically labeled reactants, the researchers traced the pathway of C atoms in the final C₂ product formed over the catalyst of Sn₁-O3G. This analysis suggested that the methyl C in the product comes from formic acid whereas the methylene C was from CO₂.

Conclusion

“Our study provides an alternative platform for C–C bond formation for ethanol synthesis and offers a strategy for manipulating CO₂ reduction pathways towards desired products,” said Prof. Huang.

Reference: “A tin-based tandem electrocatalyst for CO₂ reduction to ethanol with 80% selectivity” by Jie Ding, Hong Bin Yang, Xue-Lu Ma, Song Liu, Wei Liu, Qing Mao, Yanqiang Huang, Jun Li, Tao Zhang and Bin Liu, 30 October 2023, Nature Energy.
DOI: 10.1038/s41560-023-01389-3