Structured Porous Carbon-Based Catalysts: Cu-ZnO/CMK-3 and Cu-CeO2/CMK-3 for Direct CO2 Conversion to Methanol

N-doped ordered mesoporous carbons (NCMK-3) were synthesized using urea and ammonia as nitrogen sources via an incipient wetness impregnation method. To quantify the amount of nitrogen doping and classify the nitrogen bond formations, the XPS technique was used in this study. It was found that urea can increase the nitrogen content up to 2.54% and can classify nitrogen on NCMK-3 into three types: pyridinic-N, pyrrolic-N, and graphitic-N. Subsequently, 15 wt% of Cu-ZnO and 15 wt% of Cu-CeO2 were loaded on NCMK-3 and tested for methanol production from the CO2 hydrogenation reaction. The catalysts' performance was evaluated in a fixed-bed reactor using 0.25 g of catalyst and a CO2/H-2 (1/3) mixture at GHSV of 2444 h(-1). The results showed that 15 wt% of Cu-ZnO on the nitrogen-doped CMK-3 using urea as a nitrogen source (CZ/NCMK-3U) provided the highest space time yield (STY) of 512 mg(MeOH) g(cat)(-1) h(-1) at the reaction temperature and pressure of 250 degrees C and 1.5 MPa, respectively.