Three-dimension in-situ nitrogen doping porous cellulosic biomass-based carbon aerogel for electrocatalytic CO2 reduction

As components of biomass, cellulose has great utilization value. In this study, the three-dimensional interconnected porous structure of carbon aerogel was easily prepared from cellulose on the electrocatalytic reduction reaction of CO2 (CO2RR). However, carbon materials have fewer active sites resulting in poor catalytic activity. Therefore, in order to improve the conductivity and active sites of carbon materials, melamine as nitrogen source was added into carbon aerogel by in-situ synthesis method to prepare nitrogen uniform distribution catalyst at different pyrolysis temperature. Results showed that with the increase of pyrolysis temperature, abundant pore structures were gradually formed from inside to outside, which provided enough transport channels for CO2 and products. N3-750 had the maximum CO faradaic efficiency (FE) of 75.90% due to the largest surface area of 1038.02 m2/g and the highest surface N/C ratio of 5.15%. Meanwhile, the high content of pyridinic N provided sufficient active sites on forming the *COOH intermediate rather than the pyrrolic N. Furthermore, after eight hours of reaction, the FE of CO changed from 75.90% to 68.26%, indicating good stability. Therefore, nitrogendoped cellulosic biomass-based carbon aerogel has the potential to become a stable and efficient CO2RR catalyst.

Automated summary

In this study, a three-dimensional interconnected porous structure of carbon aerogel was prepared from cellulose and used for the electrocatalytic reduction reaction of CO2 (CO2RR). To improve the conductivity and active sites, melamine was added as a nitrogen source for in-situ synthesis of nitrogen-doped catalysts at different pyrolysis temperatures. The results showed that increasing the pyrolysis temperature gradually formed abundant pore structures that provided sufficient transport channels for CO2 and products. N3-750 exhibited the highest CO faradaic efficiency (FE) of 75.90% due to its large surface area and high surface N/C ratio. The high content of pyridinic N provided enough active sites for the formation of *COOH intermediate. Furthermore, the catalyst showed good stability as evidenced by only a slight decrease in CO FE after eight hours of reaction. Therefore, the nitrogen-doped cellulosic biomass-based carbon aerogel has the potential to be a stable and efficient CO2RR catalyst.