School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Jiangsu Key Laboratory of Vehicle Emissions Control, Nanjing 210023, China; School of Environment, Nanjing University, Nanjing 210023, China.
J Colloid Interface Sci. 2019 Oct 15;554:611-618. doi: 10.1016/j.jcis.2019.07.039. Epub 2019 Jul 16.
NO reduction by CO was investigated over CO-pretreated CuO/MnO/γ-AlO catalysts with different metal precursors (nitrate and acetate). It was found that the catalyst prepared from acetate salts (Cu/Mn/Al-A) exhibited significantly higher activity than counterpart catalyst from nitrate precursors (Cu/Mn/Al-N). XRD, XPS and in situ DRIFT were carried out to approach the nature for the different catalytic performance. For both catalysts, copper mainly existed as CuO, but the status of manganese oxide was markedly different. Mn(IV) was predominant in Cu/Mn/Al-N and Mn(III) was enriched in Cu/Mn/Al-A. As a result, different dispersion behaviors of manganese oxide on γ-AlO were displayed, which induced inconsistent Cu-Mn contact. The catalyst obtained from acetate precursor exhibited enriched Cu-Mn contact and thus more Cu-□-Mn entities would be produced after CO pretreatment, leading to promoted NO dissociation and favorable performance in NO reduction by CO. The present study sheds light on the effective tuning of Cu-O-Mn interfacial sites in CuO/MnO/γ-AlO via modulating the dispersion behaviors of surface components.
研究了在不同金属前体（硝酸盐和醋酸盐）预处理的 CuO/MnO/γ-Al2O3 催化剂上 CO 对 NO 没有还原作用。结果发现，由醋酸盐制备的催化剂（Cu/Mn/Al-A）比由硝酸盐前体制备的对应催化剂（Cu/Mn/Al-N）具有更高的活性。通过 XRD、XPS 和原位 DRIFT 对不同催化性能的本质进行了探讨。对于两种催化剂，铜主要以 CuO 的形式存在，但氧化锰的状态明显不同。Cu/Mn/Al-N 中主要存在 Mn(IV)，而 Cu/Mn/Al-A 中 Mn(III)富集。结果，γ-Al2O3 上的氧化锰表现出不同的分散行为，导致 Cu-Mn 接触不一致。由醋酸盐前体制备的催化剂表现出丰富的 Cu-Mn 接触，因此在 CO 预处理后会产生更多的 Cu-□-Mn 实体，从而促进 NO 的解离，在 CO 还原 NO 中表现出良好的性能。本研究通过调节表面成分的分散行为，为在 CuO/MnO/γ-Al2O3 中有效调节 Cu-O-Mn 界面位提供了思路。
