A group of Chinese researchers from Hainan University in Haikou and Fudan University in Shanghai has developed a new type of catalyst for converting carbon dioxide into formate, a valuable chemical compound that can be used as a fuel or an industrial raw material. The main advantage of the resulting catalyst is its self-healing ability.
The catalyst is based on a compound of indium and sulfur supplemented with magnesium, which makes the structure stronger and more stable. As a rule, these materials degrade during operation: their crystals get destroyed, their active centers lose efficiency and the catalyst stops working. However, the Chinese scientists have managed to achieve stability due to the material’s ability to restore its structure. Regeneration became possible thanks to the fact that sulfur atoms washed out during the reaction were able to go back, restoring the active sites. As a result, the catalyst maintained high efficiency for more than 200 hours, an outstanding result for systems of this kind.
In the course of the study, several versions of the catalyst were developed simultaneously, including one made of regular indium sulfide and one modified with magnesium. It was the latter that demonstrated significantly better characteristics. It became particularly active after special heat treatment at 450°C, providing a current density of up to 210 mA/cm² with a formate yield of up to 97.5% under optimal conditions.
The efficiency and stability of the material were tested in a special flow electrochemical cell. To analyze the reaction products, various methods were used, including spectroscopy, microscopy and computer modeling. Calculations confirmed that the process of losing and recovering sulfur atoms is feasible from an energy viewpoint and effective under operating conditions.
This study of the Chinese scientists opens up new possibilities for creating durable catalysts that can effectively capture and process CO₂.
