Catalytic reduction of NO over copper supported on activated carbon

Nitrogen oxides are involved in environmental pollution phenomena, making it important to develop techniques for treating the emissions of these gases. The selective catalytic reduction of NOx with carbon is an alternative technology to the more common reduction processes using NH3. This work's main objective is the synthesis of carbon catalysts, catalytically active in NO reduction. The activated carbons were subjected to appropriate treatments to modify their surface chemistry (introduction of nitrogen and oxygen functionalities and copper as metallic phase). Activated carbons prepared without metal do not show significant activity in the catalytic reduction of NO; therefore, the presence of copper in the catalysts is indispensable for obtaining high activities. The introduction of nitrogen surface groups further enhances their performance. An ideal copper-to-carbon mass ratio of 10% was obtained, with the highest NO reduction being observed for the AC_M_BM@10Cu sample, resulting in a 100% conversion for a temperature of 440 °C. For this type of catalyst, the presence of N2 and CO2 was confirmed; N2O and CO were not detected.The catalyst stability was evaluated by carrying out a long-term reaction test. Some catalyst deactivation was observed after 38 h of reaction. An ideal copper-to-carbon mass ratio of 10% was obtained, with the highest NO reduction being observed for the AC_M_BM@10Cu sample, resulting in a 100% conversion for a temperature of 440 °C. For this type of catalyst, the presence of N2 and CO2 was confirmed; N2O and CO were not detected. [Display omitted] •Activated carbons (AC) were used as a catalyst and external reducing agents.•AC with different textural and surface chemical properties was used as support.•The incorporation of nitrogen groups improves the catalytic activity.•The presence of copper in the catalysts is indispensable for obtaining high activities.•AC properties, as metal support, have a relevant role in NO reduction.