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研究了Pt/MgO,Pt/γAl2O3Pt/ZrO2和Pt/HZSM-5催化剂上H选择催化还原消除NOxH2SCR)反应.结果发现,H2SCR活性和N2生成选择性受催化剂中Pt的金属性以及载体的氮氧化物吸附能力影响很大.HZSM-5的表面酸性使载体对NO吸附能力较小,使担载Pt以较高的金属性存在,从而导致Pt/HZSM-5催化剂的高活性和高选择性.相反,Pt/MgO和Pt/γAl2O3催化剂较差的活性和选择性可归因于其载体的碱性表面、催化剂中Pt较低的金属性以及载体对氮氧化物较大的吸附能力.结合反应的原位红外光谱结果可以认为,在Pt/载体界面处亚硝酸根/硝酸根物种被还原为N2或N2O取决于该处参与反应的活性H与这些含氮物种的相对数目.
The results show that the selectivity of H2SCR and the formation of N2 are affected by the metallicity of Pt in the catalyst and the nitrogen oxides of the support The adsorption capacity of HZSM-5 has a great influence on the surface acidity of HZSM-5, which makes the carrier less able to adsorb NO and makes Pt carry higher metality, resulting in high activity and high selectivity of Pt / HZSM-5 catalyst. In contrast, the poorer activity and selectivity of the Pt / MgO and Pt / γAl2O3 catalysts are attributed to the basic surface of the support, the lower Pt content in the catalyst, and the larger adsorption capacity of the support to NOx. In-situ FTIR results suggest that the reduction of nitrite / nitrate species to N 2 or N 2 O at the Pt / support interface depends on the relative number of active Hs involved in the reaction there with these nitrogen-containing species.