Fuchigami Teruaki, Kimata Ryosuke, Haneda Masaaki, Kakimoto Ken-Ichi
Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
Advanced Ceramics Research Center, Nagoya Institute of Technology, Gifu 507-0071, Japan.
Nanomaterials (Basel). 2018 Aug 26;8(9):662. doi: 10.3390/nano8090662.
Highly stable and active low-temperature CO oxidation catalysts without noble metals are desirable to achieve a sustainable society. While zero-dimensional to three-dimensional Co₃O₄ nanoparticles show high catalytic activity, simple-structured nanocrystals easily self-aggregate and become sintered during catalytic reaction. Thus, complex three-dimensional nanostructures with high stability are of considerable interest. However, the controlled synthesis of complex nanoscale shapes remains a great challenge as no synthesis theory has been established. In this study, 100 nm raspberry-shaped nanoparticles composed of 7⁻8 nm Co₃O₄ nanoparticles were synthesized by hydrothermally treating cobalt glycolate solution with sodium sulfate. Surface single nanometer-scale structures with large surface areas of 89 m²·g and abundant oxygen vacancies were produced. The sulfate ions functioned as bridging ligands to promote self-assembly and suppress particle growth. The Co₃O₄ nano-raspberry was highly stable under catalytic tests at 350 °C and achieved nearly 100% CO conversion at room temperature. The addition of bridging ligands is an effective method to control the formation of complex but ordered three-dimensional nanostructures that possessed extreme thermal and chemical stability and exhibited high performance.
为实现可持续发展社会，人们期望获得高度稳定且活性高的无贵金属低温CO氧化催化剂。虽然零维到三维的Co₃O₄纳米颗粒具有高催化活性，但结构简单的纳米晶体在催化反应过程中容易自聚集并烧结。因此，具有高稳定性的复杂三维纳米结构备受关注。然而，由于尚未建立合成理论，复杂纳米级形状的可控合成仍然是一个巨大挑战。在本研究中，通过用硫酸钠对乙醇酸钴溶液进行水热处理，合成了由7⁻8 nm Co₃O₄纳米颗粒组成的100 nm覆盆子状纳米颗粒。制备出了具有89 m²·g大表面积和丰富氧空位的表面单纳米级结构。硫酸根离子作为桥连配体发挥作用，促进自组装并抑制颗粒生长。Co₃O₄纳米覆盆子在350 °C催化测试下高度稳定，在室温下实现了近100%的CO转化率。添加桥连配体是控制形成具有极高热稳定性和化学稳定性并表现出高性能的复杂但有序三维纳米结构的有效方法。
