Topic
NOx
About: NOx is a research topic. Over the lifetime, 26367 publications have been published within this topic receiving 496555 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, the location of copper cations in the zeolite pores and the effect of temperature on these sites and on framework stability were investigated using Rietveld refinement of variable-temperature XRD synchrotron data.
Abstract: Nitrogen oxides (NOx) are a major atmospheric pollutant produced through the combustion of fossil fuels in internal combustion engines. Copper-exchanged zeolites are promising as selective catalytic reduction catalysts for the direct conversion of NO into N2 and O2, and recent reports have shown the enhanced performance of Cu-CHA catalysts over other zeolite frameworks in the NO decomposition of exhaust gas streams. In the present study, Rietveld refinement of variable-temperature XRD synchrotron data obtained for Cu-SSZ-13 and Cu-SSZ-16 is used to investigate the location of copper cations in the zeolite pores and the effect of temperature on these sites and on framework stability. The XRD patterns show that the thermal stability of SSZ-13 is increased significantly when copper is exchanged into the framework compared with the acid form of the zeolite, H-SSZ-13. Cu-SSZ-13 is also more thermally stable than Cu-SSZ-16. From the refined diffraction patterns, the atomic positions of atoms, copper locations a...
369 citations
TL;DR: In this paper, a single cylinder research engine was used to experimentally determine the effects of fuel injection strategies and injection timings on engine combustion, performance and emission characteristics, and the experiments were conducted at constant speed (2500-rpm) with two FIPs (500 and 1000 bars respectively) and different start of injection (SOI) timings.
366 citations
TL;DR: In this article, a numerical study of the chemical effects of carbon dioxide addition on both the fuel side and the oxidizer side of a diffusion flame was conducted in an attempt to explore the chemistry mechanism of the experimentally observed soot suppression by carbon dioxide adding.
364 citations
TL;DR: Diffuse reflectance infrared Fourier transform spectroscopy studies showed that the synergetic effect between Mn and Ce contributes to the formation of reactive intermediate species, thus promoting the NH3-SCR to proceed.
Abstract: Mn-Ce-Ti mixed-oxide catalyst prepared by the hydrothermal method was investigated for the selective catalytic reduction (SCR) of NOx with NH3 in the presence of oxygen. It was found that the environmentally benign Mn-Ce-Ti catalyst exhibited excellent NH3-SCR activity and strong resistance against H2O and SO2 with a broad operation temperature window, which is very competitive for the practical application in controlling the NOx emission from diesel engines. On the basis of the catalyst characterization, the dual redox cycles (Mn4+ + Ce3+ Mn3+ + Ce4+, Mn4+ + Ti3+ Mn3+ + Ti4+) and the amorphous structure play key roles for the high catalytic deNO(x) performance. Diffuse reflectance infrared Fourier transform spectroscopy studies showed that the synergetic effect between Mn and Ce contributes to the formation of reactive intermediate species, thus promoting the NH3-SCR to proceed.
362 citations
Patent•
25 Feb 2008TL;DR: In this article, an internal combustion engine with an HC treatment catalyst having the function of adsorbing the HC in the exhaust gas is arranged upstream of the NOx selective reducing catalyst.
Abstract: An internal combustion engine wherein an HC treatment catalyst (12) having the function of adsorbing the HC in the exhaust gas is arranged upstream of the NOx selective reducing catalyst (14), an urea aqueous solution fed from the reducing agent feed valve (15) is arranged upstream of the HC treatment catalyst (12), urea, and NOx contained in the exhaust gas, and HC adsorbed on the HC treatment catalyst 12 are reacted with each other to form intermediate products having cyano groups, oximes, and amino groups, and these intermediate products are sent to the NOx selective reducing catalyst (14).
361 citations