title: N2O decomposition by mesoporous silica supported Rh catalysts.
abstract: Nitrous oxide (N(2)O), a greenhouse gas produced by nitric acid and adipic acid plants, damages the ozone layer and causes many environmental problems. The potential of MCM-41, SBA-15-Conventional (SBA-15-C), SBA-15-Spherical (SBA-15-S) and KIT-6 supported Rh catalysts has been explored at specific conditions for N(2)O decomposition in order to investigate the characteristics of new catalyst supports (SBA-15-S, KIT-6) for this application. A Rh metal loading of 1 wt% was impregnated to synthesize mesoporous silica supported Rh catalysts. The catalysts were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), N(2) adsorption/desorption, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and CO-chemisorption techniques. Of all the catalysts, Rh/SBA-15-S not only showed the highest activity, but also the best strength against ageing impact, O(2) inhibiting effect and long-term stability. The higher metal dispersion due to the smaller Rh particle size and a greater formation of Rh(+1) than Rh(0) or Rh(+3) on SBA-15-S compared to the other supports, favoured a higher N(2)O decomposition. The larger pore size of SBA-15-S in Rh/SBA-15-S might favour a better Rh access, diffusion and dispersion and lead to higher activity. The higher long-term stability of Rh/SBA-15-S, with preserved support characteristics, than the other supports indicates its significance.
authors: Department of Materials Science and Chemical Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
authors: Murid
authors: M
authors: Hussain
authors: Debora
authors: D
authors: Fino
authors: Nunzio
authors: N
authors: Russo
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D002384:Catalysis; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009609:Nitrous Oxide / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*; D012822:Silicon Dioxide / Q000138:chemical synthesis / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D014961:X-Ray Diffraction
chemical_list: D000393:Air Pollutants; D012822:Silicon Dioxide; D012238:Rhodium; D009609:Nitrous Oxide; D010100:Oxygen