Abstract: In order to study the application of construction waste sawdust in environment protection, nitrogen doped porous carbon materials were prepared by one-step pyrolysis method with NaNH₂ as activator and nitrogen source. The samples were characterized by X-ray diffraction, X-ray photoelectron, N₂ adsorption-desorption isotherm and other methods. It is found that the samples are mainly composed of micropores. Synergism of the large specific surface area and high nitrogen content provide abundant catalytically active sites and CO₂ reactant for electrochemical CO₂ reduction reaction. The electrochemical test suggests that CO is the main product in CO₂ electrochemical reduction, the Faraday efficiency of CO is up to 82% at the overpotential of -0.7 V (reversible hydrogen electrode, RHE). More importantly, the electrolysis can be maintain as long as 18 h. The results indicate that construction waste sawdust derived porous carbons effectively reduce CO₂ and realize the application in the field of environment protection.

Key words: waste sawdust, NaNH₂, electrochemistry, CO₂ reduction, CO