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61.
The surface structure of the oxidized and ammonia dissolved MoO3/-Al2O3 samples and the adsorption characteristics of the sulfided samples were investigated by Laser Raman Spectroscopy (LRS) and Low Temperature Infrared Spectroscopy (LTIR) techniques.It was verified that there were two kinds of coordinated unsaturated Mo sites (denoted as MoA(CUS) and MoB(CUS)) on the surface and the precursors of MoA(CUS) and MoB(CUS) were Mo(O) and Mo(T), respectively. It was also concluded that MoA(CUS) sites could adsorb NO and CO, while MoB(CUS) could adsorb CO only. The surface concentration of MoA(CUS) might be far smaller than that of MoB(CUS). 相似文献
62.
Giuseppe Spoto Silvia Bordiga Domenica Scarano Adriano Zecchina 《Catalysis Letters》1992,13(1-2):39-44
In this note an exchange procedure of the acidic protons of H-ZSM5 by CuI ions through reaction with CuCl in the gas phase is described. In the so obtained CuI-ZSM5 exchanged zeolite the CuI ions are in well defined configuration and form with NO mono and di-nitrosyl complexes of high structural and spectroscopic quality. The CuI(NO)2 species are transformed at RT into CuII(NO)X (X=O– and/or NO
2
–
) species which could represent an intermediate in NO decomposition. 相似文献
63.
采用低负载量的(0~3%)Ag/γ-A12O3体系作为C3H6选择性催化还原(C3H3-SCR)NO的催化剂,考察了银负载量、反应温度、空速对NO转化率的影响.同时对于原料气中氧的作用进行了研究.结果表明:银负载量为1.5%时,催化剂表现出最高的反应活性;在考察的条件范围内,原料气中含氧对NO的还原有促进作用,适宜的氧浓度为0.27%;反应温度的过高会导致还原气中C3H6大幅度转化为CO2。 相似文献
64.
NO removal using CH4 as a reductant in a dual-bed system has been investigated with Co-NaX and Ag-NaX catalysts, which were prepared by Co2+-, Ag+-ion exchange into zeolite NaX, respectively, and activation for 5 h at 500 °C. The experimental result has been compared with that of a Co-NaX-CO catalyst, additionally pre-treated under CO flow for the Co-NaX catalyst. The cobalt crystal structure of a Co-NaX-CO catalyst is Co3O4, which promotes NO oxidation to NO2 by excess O2 at a low temperature (523 K). The mechanical mixture of Co-NaX-CO and Ag-NaX catalysts shows a synergy effect on NO reduction to N2 by CH4 in the presence of excess O2 and H2O, but the NO reduction decreases quickly as time passes. However, the NO reduction to N2 in a deNO bed at 523 K and a deNO2 bed at 423 K, which are relatively lower than the reaction temperatures for common SCR systems, still remained at 67% even in a H2O 10% gas mixture after 160 min. 相似文献
65.
The H2/NO/O2 reaction under lean-burn conditions has been studied by means of in situ DRIFTS, reactor measurements and temperature-programmed desorption with the aim of understanding the very different behavior of Pd/TiO2 and Pd/Al2O3 catalysts. The former deliver very high NO
x
conversions (70-80%) with good N2 selectivity whereas the latter show very low activity. In addition, PdTiO2 exhibits two distinct NO
x
reduction pathways, thus greatly extending the useful temperature range. It is shown that the PdTiO2 low-temperature channel involves adsorption and subsequent dissociation of NO on reduced (Pd0) metal sites. The low activity of PdAl2O3 is a consequence of palladium remaining in an oxidized state under reaction conditions. The high-temperature NO reduction channel found with PdTiO2 is associated with the generation and subsequent reaction of NH
x
species. 相似文献
66.
Simulation of swirling combustion and NO formation using a USM turbulence-chemistry model 总被引:1,自引:0,他引:1
A unified second-order moment (USM) turbulence-chemistry model is used to simulate methane-air swirling combustion and NO formation for different swirl numbers. The simulation results are compared with those using the EBU-Arrhenius (E-A) combustion model, the simplified PDF model of NO formation in turbulent flows and the corresponding experimental results. The comparison indicates that the USM model is obviously better than the E-A model and the simplified PDF model. The E-A model cannot reasonably simulate the finite-rate kinetics, while the simplified PDF model, using a product of two single-variable PDF's instead of a joint PDF, remarkably under-predicts the NO reaction rate. The USM model gives the best agreement with the experimental results. Predictions show that as the swirl number increases the total NO formation at first decreases and then increases, which is in agreement with the experimental results. 相似文献
67.
Mechanism analysis on simultaneous oxidation of NO and SO2 with additives was presented and numerical simulation was developed to investigate the performances of three additives on oxidation of NO and SO2. The simulation result showed that reaction temperature, residence time, additive dose and NO concentration influence the oxidation process significantly. There exists an optimum reaction condition for each additive. n-C4H10 has the strongest ability to oxidize NO and SO2. 相似文献
68.
69.
The catalytic reduction of NO over activated carbons (ACs)/Cu prepared by electroless copper plating has been studied. It is found that copper content on carbon surfaces increased with increasing plating time. However, a slightly gradual decrease of adsorption properties as electroless plating time increases, including specific surface areas and total micropore volumes based on D-R and t-plot approaches, is observed within the range of well-developed micropore structures. The experimental results showed that the net heat of adsorption or BET's C of the AC/Cu samples is largely influenced by the amount of copper metal. Consequently, the catalytic ability of AC/Cu samples for NO removal is dependent on the copper content, adsorption properties of the specimens, and the reaction time on stream in the presence of oxygen. 相似文献
70.
Ning Li Aiqin Wang Lili Ren Mingyuan Zheng Xiaodong Wang Tao Zhang 《Topics in Catalysis》2004,(1):103-105
Sulfated alumina (SA) is firstly found to be an effective support for Pd catalyst used in the SCR of NO with methane. The sulfation is important to increase support's acidity which is essential for the reduction of NO over Pd catalysts. On consideration of the lower cost and easier availability of SA, we believe that SA is more promising to act as the commercial support for Pd catalyst used in the SCR of NO with methane. 相似文献