Catalytic Reduction of NO with NH 3 over V 2 O 5 -MnO X /TiO 2 -Carbon Nanotube Composites
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Catalytic Reduction of NO with NH3 over V2O5-MnOX/TiO2Carbon Nanotube Composites Qian Li • Hangsheng Yang • Anmin Nie Xiaoyu Fan • Xiaobin Zhang
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Received: 5 March 2011 / Accepted: 6 May 2011 / Published online: 20 May 2011 Ó Springer Science+Business Media, LLC 2011
Abstract A series of V2O5–MnOX/TiO2-CNTs, V2O5/ TiO2-CNTs, and MnOX/TiO2-CNTs catalysts were synthesized via solvothermal method and their NOX removal activities were studied. A catalytic performance improvement was observed over catalysts prepared by mechanical mixing MnOX/TiO2-CNTs and V2O5/TiO2-CNTs. XRD, SEM, EDS, TPD, TPR, and BET were employed to analyze the improvement which is ascribed to the separation of Mn and V as well as the increase in reducibility and acidic strength. Keywords
De-NOX V2O5 MnOX SCR
1 Introduction Nitrogen oxides (NOX) discharged from power plants, waste incinerators, industrial boilers, engines, and automotives can result in worldwide concerns such as acid rain, photochemical smog, and ozone depletion. Due to the increasing threat of NOX to the environment, a series of methods have been developed to control NOX emission; and selective catalytic reduction (SCR) has been proven to be an effective method [1, 2]. A large number of SCR catalysts including noble metals [3, 4], transition metal oxides [2, 5, 6], and zeolite [7, 8] have been optimized in literature. V2O5–TiO2 catalysts, usually upgraded to V2O5–WO3/TiO2, have been applied extensively in the industry. However, the operation
Q. Li H. Yang (&) A. Nie X. Fan X. Zhang Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Zheda Road 38, Hangzhou 310027, China e-mail: [email protected]
temperature of these catalysts is usually above 300 °C and the exhaust gases contain a large number of ash and SO2, which hastens catalyst deactivation. It is therefore of great interest to develop low-temperature SCR catalysts located in the circulating downstream after the desulfurizer and electrostatic precipitator. Relatively low-temperature catalysts not only contribute to lower energy consumption, but also help simplify the retrofitting of SCR devices for flue gas cleaning [9]. A series of catalysts, including V2O5/AC [10], V2O5/ CNTs [11], Mn–Ce/TiO2 [12], MnOX [13], and MnOX– CeO2 [14] have been reported to present high activity at relatively low-temperatures. At the same time, introducing other metal oxides to traditional V2O5–TiO2 and MnOX– CeO2 catalysts was proposed to improve NOX removal efficiency. Lietti et al. [15] and Casagrande et al. [5] explained the promotion effect of WO3 and MoO3 to V2O5– TiO2. Amiridis et al. [16] screened the effect of introducing metal oxides to V2O5/TiO2 and found that WO3 and MoO3 exhibit the most significant promotion of the catalyst, whereas MnO2, Ga2O3, La2O3, SnO2, and ZnO appear to poison the catalyst. Phil et al. [17] reported that Se-, Sb-, Cu-, and S-doped V2O5/TiO2 catalysts show high catalytic activity for NH3–SCR of NOX at temperatures between 150 and 400
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