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 degrees 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 degrees C. For this type of catalyst, the presence of N2 and CO2 was confirmed; N2O and CO were not detected.

Automated summary

Nitrogen oxides play a significant role in environmental pollution, highlighting the importance of developing techniques to treat these gas emissions. The selective catalytic reduction of NOx with carbon, instead of NH3, is a promising alternative technology. This study focuses on synthesizing carbon catalysts that are effective in reducing NO emissions. Surface modifications, including introducing nitrogen and oxygen functionalities and copper as a metallic phase, significantly enhance the catalytic activity. The optimal copper-to-carbon mass ratio of 10% leads to 100% NO conversion at 440 degrees C, indicating the high performance of the AC_M_BM@10Cu catalyst. The presence of N2 and CO2 was confirmed, while N2O and CO were not detected. Some catalyst deactivation was observed after 38 hours of reaction.