CAJ | 학술논문

采用原位红外光谱研究了在具有短程有序Ce-O-Ti结构的非晶Ce-Ti氧化物上NH3选择性催化还原(SCR) NOx反应.在反应条件下,催化剂表面主要被NH3吸附物种覆盖,而检测不到NOx吸附物种.经测定, NO的反应级数为0.5-0.6,表明Langmuir-Hinshelwood机理和Eley-Rideal机理同时存在.可能的机理是NH3吸附物种和弱吸附的NOx反应,生成NHyNO3(y =0-4)活性中间物种,并通过GAUSSIAN计算和原位红外结果证实了它们的存在. Ce-O-Ti结构中Ce与Ti之间表现出原子尺度的相互作用,所以在SCR反应的活性温度窗口下,催化剂的氧化还原活性提高.
채용원위홍외광보연구료재구유단정유서Ce-O-Ti결구적비정Ce-Ti양화물상NH3선택성최화환원(SCR) NOx반응.재반응조건하,최화제표면주요피NH3흡부물충복개,이검측불도NOx흡부물충.경측정, NO적반응급수위0.5-0.6,표명Langmuir-Hinshelwood궤리화Eley-Rideal궤리동시존재.가능적궤리시NH3흡부물충화약흡부적NOx반응,생성NHyNO3(y =0-4)활성중간물충,병통과GAUSSIAN계산화원위홍외결과증실료타문적존재. Ce-O-Ti결구중Ce여Ti지간표현출원자척도적상호작용,소이재SCR반응적활성온도창구하,최화제적양화환원활성제고.
A series of in situ infrared (IR) studies of the selective catalytic reduction (SCR) of NOx with NH3 on the short-range ordered structure Ce-O-Ti sites in amorphous Ce-Ti mixed oxides were performed. Under the reaction conditions, the catalyst surface was mainly covered by NH3 ad-species and no NOx ad-species were detected. The reaction order of 0.5-0.6 with respect to NO confirmed a hybrid Langmuir-Hinshelwood and Eley-Rideal mechanism. A possible route may involve the reaction of NH3 ad-species and weakly adsorbed NOx to form an active intermediate, NHyNO3 (y=0-4);this was confirmed by GAUSSIAN calculations and the in situ IR results. The Ce-O-Ti structure, with Ce-Ti interactions on the atomic scale, enhanced the redox properties in the active temperature window of the SCR reactions.