N-Doped Carbon–Silica Composite Confined Pd Nanoparticles for Abatement of Methane Emission From Automobiles
- 64 Downloads
Natural gas vehicles, as well as some other engines in automobiles, emit methane, which is a potent greenhouse gas. Developing advanced catalysts that can oxidize methane with good and stable activity is required for new emission standards of automobiles. We report here a N-doped carbon–silica composite that can well disperse Pd nanoparticles and preserve part of active Pd nanoparticles (< 8 nm) under typical conditions of exhaust gas from a working engine. Comparative studies indicate a stronger metal-support interaction between Pd nanoparticle and N-doped carbon (NC) than none N-doped carbon. A facile silica coating is formed from SiCl4 in water vapor. The silica coating encapsulates Pd/NC and prevents extreme Pd sintering. The Pd catalyst with N-doped carbon–silica composite, i.e. (Pd/NC)@SiO2, performs stable and complete conversion of 5000 ppm CH4 to CO2 and H2O at 350 °C with a space velocity of 40,000 cm3 per gram of catalyst per hour. This research illustrates the advantage of using N-doped carbons supported catalyst for methane oxidation. Future optimization could be attempted by improving the thermal stability of carbons at the reaction conditions.
KeywordsPalladium Methane emission Nanoparticle sintering Metal-support interaction N-doped carbons Silica coating
This work was supported by the National Natural Science Foundation of China (Grant No. 51761135111). The authors would like to thank Mrs. Xinqiu Guo, Mrs. Jing Liu and Ms. Jinghan Li from Instrument Analysis Center of Shanghai Jiao Tong University (SJTU-IAC) for great support of TEM characterization. Many thanks to Mrs. Ting Cheng from SJTU-IAC for assisting micropore analysis, and Mr. Weiqi Guo for his kind help in H2-TPR measurements.
- 11.Hicks RF, Young HQI, Lee ML RG (1990) ChemInform abstract: effect of catalyst structure on methane oxidation over palladium on alumina. Cheminform 122(28):295–306Google Scholar
- 29.Kai T, Pan X, He L, Li P, Yu T, Bao X (2018) Pd supported on NC@SiC as an efficient and stable catalyst for 4-carboxybenzaldehyde hydrogenation. Catal Commun 110:79–82Google Scholar
- 34.Chen YJ, Xiao G, Wang TS, Ouyang QY, Qi LH, Ma Y, Gao P, Zhu CL, Cao MS, Jin HB (2011) Porous Fe3O4/carbon core/shell nanorods: synthesis and electromagnetic properties. J Phys Chem C 115(28):10061–10064Google Scholar