The electrochemical CO₂ reduction reaction (CO₂ERR) could enable environmentally friendly carbon utilization and value-added chemicals production. Formate and syngas (a mixture of hydrogen and carbon monoxide) are two typical products of the CO₂ERR. They can be used as hydrogen storage materials and chemical feedstocks for the Fischer–Tropsch synthesis of hydrocarbons, respectively. The co-production of these two products maximizes the efficiency of electrochemical CO₂ conversion.

Jinlong Gong, Tianjin University, China, and colleagues have synthesized ultrasmall SnO₂ nanodots (NDs) homogeneously anchored on carbon nanotubes (CNT#SnO₂ NDs) to be used as electrocatalysts for the CO₂ERR process. The CNT#SnO₂ NDs were prepared from COOH‐functionalized CNTs and SnCl₄⋅5 H₂O in an aqueous solution of glycine, hydrochloric acid, and ethylene glycol using ultrasonication.

The obtained CNT#SnO₂ NDs can be coupled with oxygen evolution reaction (OER) catalysts. This results in a CO₂ERR-OER electrolyzer with a low driven voltage of approximately 2 V. It can be used for the long-term co-production of formate and syngas. The high activity and selectivity of this system are stable for up to 24 h.

• Selective Electro-Reduction of Carbon Dioxide over SnO₂-Nanodot Catalysts,
  Jinlong Gong, Congling Hu, Lulu Li, Wanyu Deng, Gong Zhang, Wenjin Zhu, Xintong Yuan, Lei Zhang, Zhi-Jian Zhao,
  ChemSusChem 2020.
  https://doi.org/10.1002/cssc.202000557