In situ monitoring of DeNOx-SCR on zeolite catalysts by means of simultaneous impedance and DRIFT spectroscopy
In situ monitoring of DeNOx-SCR on zeolite catalysts by means of simultaneous impedance and DRIFT spectroscopy
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DOI：
10.1016/j.proeng.2015.08.600
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Peirong Chen;Simon Schönebaum;T. Simons;D. Rauch;R. Moos;U. Simon
中科院分区：
文献类型：
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作者：
Peirong Chen;Simon Schönebaum;T. Simons;D. Rauch;R. Moos;U. Simon
为了开发更高效的选择性催化还原NOx（DeNOx-SCR）的沸石催化剂，需要对催化剂的实时状态（如nh3储存水平）和反应机理进行分析。阻抗谱（IS）允许电感测nh3进入质子导电催化剂的吸收。在80 ~ 450℃的温度范围内，Cu-SAPO对nh3的响应高于Cu-ZSM-5。因此，IS可以用来确定nh3的储存和监测SCR反应的原位。同时进行IS和DRIFTS研究表明，Cu- sapo的质子电导率与硝酸铵中间体nh3结合在Cu位点和Brønsted酸位点有关。然而，在不同的反应条件下，每种物质对电导率的贡献是不同的。这种积分电响应与分子过程的关联为分子筛催化SCR反应的状态监测和机理理解开辟了新的途径。
The development of more efficient zeolite catalyst for selective catalytic reduction of NOx(DeNOx-SCR) requires the analysis of the real-time state of the catalyst (e.g. NH3storage level) and the reaction mechanism. Impedance spectroscopy (IS) allows to electrically sense the uptake of NH3into proton conducting catalysts. By means of IS we reveal that Cu-SAPO possesses higher response to NH3than Cu-ZSM-5 over a broad temperature range from 80 °C to 450 °C. IS can thus be used to determine the NH3storage and to monitor the SCR reactionin situ. Simultaneous IS and DRIFTS study underin situconditions unveiled that the proton conductivity of Cu-SAPO is related to the ammonium nitrate intermediate, NH3species bounded to both Cu sites and Brønsted acid sites. However, the contribution of each species to the conductivity varied in different reaction conditions. This correlation of integral electrical response with molecular processes paves a new route for thein situmonitoring and mechanistic understanding of zeolite-catalyzed SCR reactions.