Cu、Fe掺杂六铝酸盐催化剂的催化还原脱硝性能

Catalytic reduction activity of SrCu_xFe_(1-x)Al_(11)O_(19-δ) hexaaluminate catalysts for deNOx

采用共沉淀法制备Cu和Fe掺杂的六铝酸盐催化剂(SrCuxFe1-xAl11O19-δ,x=0、0.2、0.4、0.5、0.6、0.8、1),通过XRD、H2-TPR和BET等方法对催化剂结构及性能进行研究,并考察以CO为还原剂的催化脱硝活性。结果表明,用碳酸铵作为沉淀剂在1 200℃焙烧4 h可形成完整的六铝酸盐晶型,Cu和Fe能取代Al3+,较好地促进六铝酸盐晶体结构的形成;SrCuxFe1-xAl11O19-δ催化剂脱硝催化活性较好,在温度不超过450℃和空速6 000 h-1条件下,均使NO转化率超过99%。在SrCuxFe1-xAl11O19-δ六铝酸盐催化剂中,Cu和Fe均为催化脱硝的主要活性元素,两种元素按一定量配比更有利于提升脱硝效果,最优催化剂为SrCu0.5Fe0.5Al11O19-δ。

Abstract： Cu and Fe substituted hexaaluminates catalysts （ SrCuxFe1-xAl11O19-δ x=0, 0. 2,0. 4,0. 5, 0.6,0. 8,1 ） were prepared with co-precipitation method. The structure and physicochemical properties of the samples were characterized by means of XRD, H2-TPR and BET techniques. The deNOx activity of as-prepared samples were investigated in a miniature fixed bed reactor using CO as the reducer. The results showed that the catalyst prepared using （NH4）2CO3 as the precipitant possessed good hexaaluminate phase at calcination temperature 1 200 ℃ for 4 h. Cu and Fe contributed to forming the hexaaluminate lattice due to their good synergistic reaction. Among all the samples,SrCuxFe1-xAl11O19-δ catalysts exhibited the highest catalytic activity in deNOx reaction. NO conversion of over 99% on SrCuxFe1-xAl11O19-δ catalysts was attained under the condition of reaction temperature below 450 ℃ and space velocity 6 000 h-1. Both Cu and Fe inSrCuxFe1-xAl11O19-δcatalysts were the main active elements for deNOx reaction. A certain proportion of Cu to Fe was helpful to promote the deNOx effects of the catalysts. The best catalyst was SrCuxFe1-xAl11O19-δ.