Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, PR China.
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, PR China.
J Colloid Interface Sci. 2016 Sep 15;478:11-21. doi: 10.1016/j.jcis.2016.05.052. Epub 2016 May 27.
In this paper, a series of Cu-Fe-Ti and Co-Fe-Ti oxide catalysts were prepared by sol gel method. Cu-Fe-Ti and Co-Fe-Ti oxide catalysts showed the moderate catalytic activity for selective catalytic reduction (SCR) of NO with NH3 at low temperature. The catalysts with the molar ratio as 4:1:10 (M:Fe:Ti) were selected as the representatives for comparison of reaction properties and H2O resistance, which were denoted as Cu-Fe/TiO2 and Co-Fe/TiO2 respectively. The characterization results manifested Co-Fe/TiO2 owned more adsorption capacity of the reactants and Cu-Fe/TiO2 had better redox ability. The in situ DRIFTS experiments indicated that adsorbed NH3 species and nitrate species both exhibited reaction activity for Co-Fe/TiO2, while nitric oxide was only be reduced by adsorbed NH3 species through Eley-Rideal mechanism for Cu-Fe/TiO2 at 150°C. Co-Fe/TiO2 exhibited the better resistance to H2O and its temperature window shifted towards the higher temperature in presence of 10vol% H2O, while the SCR activity of Cu-Fe/TiO2 was inhibited significantly in the whole temperature range investigated. The suppression of adsorption and activation for NH3 and NOx might be the reasons for the reversible inactivation, which was confirmed by the inhibitation of catalytic activities for separation NH3 and NO oxidation under the wet condition. We speculated that different thermal stability of adsorbed species and redox capacity of catalysts leaded to the different SCR behavior in absence and presence of H2O.
本文采用溶胶凝胶法制备了一系列 Cu-Fe-Ti 和 Co-Fe-Ti 氧化物催化剂。Cu-Fe-Ti 和 Co-Fe-Ti 氧化物催化剂在低温下对 NH3 选择性催化还原（SCR）NO 表现出中等的催化活性。选择摩尔比为 4:1:10（M:Fe:Ti）的催化剂作为代表，比较其反应性能和抗水性能，分别表示为 Cu-Fe/TiO2 和 Co-Fe/TiO2。表征结果表明，Co-Fe/TiO2 具有更高的反应物吸附容量，而 Cu-Fe/TiO2 具有更好的氧化还原能力。原位 DRIFTS 实验表明，吸附的 NH3 物种和硝酸盐物种都对 Co-Fe/TiO2 表现出反应活性，而 Cu-Fe/TiO2 仅通过 Eley-Rideal 机制，在 150°C 下，吸附的 NH3 物种还原一氧化氮。在 10vol%H2O 存在下，Co-Fe/TiO2 对 H2O 的抗干扰能力更强，其温度窗口向高温移动，而 Cu-Fe/TiO2 在整个研究温度范围内的 SCR 活性都受到显著抑制。吸附和活化 NH3 和 NOx 的抑制可能是可逆失活的原因，这通过在湿条件下抑制 NH3 分离和 NO 氧化的催化活性得到证实。我们推测，不同吸附物种的热稳定性和催化剂的氧化还原能力导致了在有水和无水条件下不同的 SCR 行为。
