Co3O4-CuCoO2 Nanomesh: An Interface-Enhanced Substrate that Simultaneously Promotes CO Adsorption and O2 Activation in H2 Purification
Co3O4-CuCoO2 Nanomesh: An Interface-Enhanced Substrate that Simultaneously Promotes CO Adsorption and O2 Activation in H2 Purification
复制标题
Co3O4-CuCoO2 纳米网：一种界面增强基底，可同时促进 H2 纯化中的 CO 吸附和 O2 活化
DOI：
10.1021/acsami.8b19478
复制
发表时间：
2019-02-13
影响因子：
9.5
通讯作者：
Li, Guangshe
中科院分区：
文献类型：
--
作者：
Ding, Junfang;Li, Liping;Li, Guangshe
纳米材料作为氧化还原型反应催化剂被广泛应用，但其吸附和O-2活化难以同时促进，限制了其在富h -2流中优先CO氧化（CO- prox）等许多重要催化领域的应用。本文以铝粉为牺牲剂，采用水热法初步合成了界面增强型Co3O4-CuCoO2纳米网。采用粉末x射线衍射、扫描电镜、透射电镜、N-2吸附、x射线光电子能谱、紫外可见吸收光谱、拉曼光谱、x射线吸收近边光谱、氢程序升温还原、氧程序升温解吸等方法对该纳米网进行了系统表征。结果表明，纳米网具有高密度的纳米孔，使得大量的CO吸附位点暴露在表面。同时，电子从O2-向Co3+/Co2+转移，以及Co-O键在表面的键强度减弱，促进了Co3O4的氧活化和氧化还原能力。在作为CO- prox催化剂的测试中，该纳米网具有优化的孔隙结构和表面电子结构，在CO选择性氧化反应中表现出非常高的低温催化氧化活性和更宽的工作温度窗口（即CO转化率bb0 99.0%, 100-200℃）。这一发现将对寻求更好的CO-PROX催化剂有很大的帮助，这是质子交换膜燃料电池和汽车的一个热门话题。
Nanomaterials are widely used as redox-type reaction catalysts, while reactant adsorption and O-2 activation are hardly to be promoted simultaneously, restricting their applications in many important catalytic fields such as preferential CO oxidation (CO-PROX) in H-2-rich stream. In this work, an interface-enhanced Co3O4-CuCoO2 nano mesh was initially synthesized by a hydrothermal process using aluminum powder as a sacrificial agent. This nanomesh is systematically characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N-2 adsorption, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy, Raman spectroscopy, X-ray absorption near-edge spectroscopy, hydrogen temperature-programmed reduction, and oxygen temperature-programmed desorption. It is demonstrated that the nanomesh possesses high-density nanopores, enabling a large number of CO adsorption sites exposed to the surface. Meanwhile, electron transfer from O2- to Co3+/Co2+ and the weakened bonding strength of Co-O bond at surfaces promoted the oxygen activation and redox ability of Co3O4. When tested as a catalyst for CO-PROX, this nanomesh with an optimized pore structure and a surface electronic structure, exhibits a strikingly high catalytic oxidation activity at low temperatures as well as a broader operation temperature window (i.e., CO conversion >99.0%, 100-200 degrees C) in the CO selective oxidation reaction. The present finding should be highly useful in promoting the quest for better CO-PROX catalysts, a hot topic for proton exchange membrane fuel cells and automotive vehicles.