State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry , Jilin University , Changchun 130012 , P.R. China.
Fujian Institute of Research in Structure of Matter , Chinese Academy of Sciences , Fuzhou 350002 , P.R. China.
ACS Appl Mater Interfaces. 2018 Mar 7;10(9):7935-7945. doi: 10.1021/acsami.7b15549. Epub 2018 Feb 23.
Interfacial regulation offers a promising route to rationally and effectively design advanced materials for CO preferential oxidation. Herein, we initiated an interfacial regulation of CeO-CuO -RGO composites by adjusting the addition sequence of the components during the support formation. The presence of RGO along with the sequence tuning of the components is confirmed to survey the changes of the oxidation state of copper species, the content and distribution of the Cu site, and the synergistic interactions between Cu-Ce mixed oxides and reduced graphene oxide (RGO) over the catalysts. These catalysts were systematically characterized by inductively coupled plasma, X-ray diffraction, transmission electron microscopy/high-resolution transmission electron microscopy, hydrogen temperature-programmed reduction, X-ray photoelectron spectra, thermal gravimetric analysis, Raman spectra, and in situ diffuse reflectance infrared Fourier transform spectroscopy measurements. The results show that RGO is favorable for the generation of Cu and the dispersion of copper-cerium species in the as-prepared catalysts. Furthermore, by multi-interfacial regulation of the CeO-CuO -RGO composites, the catalyst CeO/CuO -RGO exhibits a strikingly high catalytic oxidation activity at a low temperature coupled with a broader operation temperature window (i.e., CO conversion >99.0%, 140-220 °C) in the CO-selective oxidation reaction, which has been attributed to the high content of the active species Cu enriched on the surface, the highly dispersed copper oxide clusters subjected to a strong interaction with ceria, and the synergistic interactions between Cu-Ce mixed oxides and RGO.
界面调控为合理有效地设计用于 CO 优先氧化的先进材料提供了一条很有前途的途径。在此，我们通过在载体形成过程中调整各组分的添加顺序，对 CeO-CuO-RGO 复合材料进行界面调控。RGO 的存在以及组分顺序的调变，证实了对铜物种氧化态、Cu 位含量和分布以及 Cu-Ce 混合氧化物与还原氧化石墨烯（RGO）之间协同相互作用的变化进行了调查。这些催化剂通过电感耦合等离子体、X 射线衍射、透射电子显微镜/高分辨率透射电子显微镜、氢气程序升温还原、X 射线光电子能谱、热重分析、拉曼光谱和原位漫反射红外傅里叶变换光谱测量进行了系统的表征。结果表明，RGO 有利于 Cu 的生成和铜铈物种在制备的催化剂中的分散。此外，通过 CeO-CuO-RGO 复合材料的多重界面调控，CeO/CuO-RGO 催化剂在 CO 选择性氧化反应中表现出极高的低温催化氧化活性，并且具有更宽的操作温度窗口（即 CO 转化率>99.0%，140-220°C），这归因于表面富含活性物质 Cu 的高含量、受到强相互作用的高度分散的氧化铜簇以及 Cu-Ce 混合氧化物和 RGO 之间的协同相互作用。
