CAJ | 학술논문

采用固相法合成系列铬钴复合氧化物催化剂,该催化体系在中低温[( 180~300 )℃]下具有优异的氨选择性催化氮氧化物还原活性,其中,Cr(0. 5)-CrOx 催化剂在空速50 000 h-1、反应温度200 ℃和220 ℃条件下,NOx转化率达100%.采用原位DRIFIS研究催化剂表面吸附物种以及催化机理,在反应温度220 ℃考察 Cr(0. 5)-CoOx 催化剂表面 NH3 与 NO 的吸附态形式和NH3 -SCR反应过程中中间态及其反应机理.结果表明,Cr(0. 5)-CrOx 催化剂上NH3 吸附在L酸位,也能吸附在B酸位,但只与气态的NOx反应,生成中间体NH2 NO,再进一步反应,最终生成N2 与H2 O.吸附态的NOx不参与SCR反应,反应遵循Eley-Rideal机理.
채용고상법합성계렬락고복합양화물최화제,해최화체계재중저온[( 180~300 )℃]하구유우이적안선택성최화담양화물환원활성,기중,Cr(0. 5)-CrOx 최화제재공속50 000 h-1、반응온도200 ℃화220 ℃조건하,NOx전화솔체100%.채용원위DRIFIS연구최화제표면흡부물충이급최화궤리,재반응온도220 ℃고찰 Cr(0. 5)-CoOx 최화제표면 NH3 여 NO 적흡부태형식화NH3 -SCR반응과정중중간태급기반응궤리.결과표명,Cr(0. 5)-CrOx 최화제상NH3 흡부재L산위,야능흡부재B산위,단지여기태적NOx반응,생성중간체NH2 NO,재진일보반응,최종생성N2 여H2 O.흡부태적NOx불삼여SCR반응,반응준순Eley-Rideal궤리.
A series of Cr-Co mixed oxide catalysts was prepared by solid states reaction method,which were used for selective catalytic reduction( SCR)of NOx with NH3 in the presence of excess oxygen at medium-low temperature[(180~300)℃]. The experimental results showed that under the condition of space velocity 50 000 h-1 and reaction temperature 200℃ and 220℃,NOx conversion reached 100% on Cr(0. 5)-CoOx catalyst. In situ diffuse reflectance infrared transform(DRIFT)spectroscopy was em-ployed for investigating the adsorption species on Cr(0. 5)-CoOx catalyst surface and revealing the reac-tion mechanism under reaction temperature 220 ℃. Based on the in situ DRIFTS results,it was found that NH3 was adsorbed on Lewis and Br?nsted acid sites of Cr(0. 5)-CrOx catalyst,and then decomposed into -NH2 . The gas phase NO could bond with -NH2 and form an intermediate NH2 NO,which could further decompose into N2 and H2 O. The adsorbed NOx didn't participate in the SCR reaction. NH3-SCR reaction on Cr(0. 5)-CoOx catalyst mainly followed the Eley-Rideal mechanism.