Carbon dioxide in the atmosphere is a major cause of man-made climate change. Converting the gas into useful chemical feedstocks is one approach to curbing its negative influence. The electrochemical reduction of CO₂ to CO is one such conversion. The reaction can be catalyzed with noble metal nanoparticles (NPs), however, aggregation of the particles reduces their catalytic activity. Support materials can help to solve this problem.

Stephen M. Lyth, Kyushu University, Fukuoka, Japan, Paul J. A. Kenis, University of Illinois at Urbana-Champaign, USA, and Kyushu University, and colleagues have developed a catalyst for the conversion of CO₂ to CO that consists of carbon foam decorated with silver nanoparticles. The team synthesized the carbon foam by thermal decomposition of sodium ethoxide. The foam was then mixed with a silver nitrate solution. Sodium citrate and NaBH₄ were added to prepare the silver nanoparticles via a reduction reaction.

The resulting material has a large surface area, high porosity, and sufficient electrical conductivity. It also ensures a good dispersion of the nanoparticles. As an electrocatalyst for the conversion of CO₂ to CO, the NP-decorated carbon foam outperforms catalysts based on other support materials such as graphene powder or carbon black.

• Carbon Foam Decorated with Silver Nanoparticles for Electrochemical CO₂ Conversion,
  Sichao Ma, Jianfeng Liu, Kazunari Sasaki, Stephen M. Lyth, Paul J. A. Kenis,
  Energy Technol. 2017.
  DOI: 10.1002/ente.201600576