制备条件对Ce/AC催化剂低温C3H6选择性催化还原NO的影响

采用浸渍法制备了一系列的Ce/AC催化剂,以C3H6为还原剂,通过程序升温反应考察其选择性催化还原NO的催化性能。着重探讨Ce含量以及焙烧温度对催化剂催化性能的影响,并用BET、XRD、XPS和SEM对催化剂进行了表征。结果表明,Ce的氧化物能在载体表面呈现出高度分散状态;随着Ce含量的增加,催化剂的比表面积逐渐降低,而NO转化率却得到提高;Ce(0.07)/AC-400的催化剂能在270℃到330℃的温度区间内保持70%以上的NO转化率;过高的焙烧温度则会对催化剂载体结构造成严重破坏,在400℃焙烧制得的催化剂具有较宽的反应温度适应范围。

Infulence of the Preparation Conditions in the Low-temperature SCR of NO with C3H6 over CeOx/AC

Catalysts with cerium oxides loaded on activated carbon prepared by impregnation are used for the selective catalytic reduction (SCR) of NO with C3H6 by temperature programmed reaction (TPR). The different loading of cerium oxides and calcination temperature is investigated in the preparation condition test. The catalysts are characterized by N2-specific surface area measurement (BET), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscope (SEM). It indicates that cerium supported on activated carbon is highly dispersed. And the specific surface area of the activated carbon is decreasing with the increasing loading of cerium oxides, but the NO conversion is increasing. Ce(0.07)/AC-400 can keep the NO conversion above 70% between 270oC to 330oC. It is benefit to NO reduction by getting a better balance between the loading amount and dispersion of cerium oxides on AC. The calcination temperature is important to the conversion of precursor, but the higher temperature may destroy the structure of AC. It is indicate that the catalyst which is calcined at 400oC can achieve wider temperature window.