Institute of Atmospheric Sciences, Shanghai Key Laboratory of Atmospheric Particle Pollution & Prevention (LAP3), Department of Environmental Science & Engineering, Fudan University , Shanghai 200433, China.
Jiangsu Collaborative Innovation Center of Atmospheric Environment & Equipment Technology (CICAEET), Nanjing University of Information Science & Technology , Nanjing 210044, China.
Environ Sci Technol. 2017 Jun 20;51(12):7084-7090. doi: 10.1021/acs.est.7b00499. Epub 2017 Jun 9.
The development of efficient alkali-based catalysts for the abatement of formaldehyde (HCHO), a ubiquitous air pollutant, is economically desirable. Here we comparatively study the catalytic performance of two single-atom catalysts, Na/HMO and Ag/HMO (HMO = Hollandite manganese oxide), in the complete oxidation of HCHO at low temperatures, in which the products are only CO and HO. These catalysts are synthesized by anchoring single sodium ions or silver atoms on HMO(001) surfaces. Synchrotron X-ray diffraction patterns with structural refinement together with transmission electron microscopy images demonstrate that single sodium ions on the HMO(001) surfaces of Na/HMO have the same local structures as silver atoms of Ag/HMO. Catalytic tests reveal that Na/HMO has higher catalytic activity in low-temperature oxidation of HCHO than Ag/HMO. X-ray photoelectron spectra and soft X-ray absorption spectra show that the surface lattice oxygen of Na/HMO has a higher electronic density than that of Ag/HMO, which is responsible for its higher catalytic efficiency in the oxidation of HCHO. This work could assist the rational design of cheap alkali metal catalysts for controlling the emissions of volatile organic compounds such as HCHO.
开发高效的碱性催化剂来消除甲醛（HCHO）是很有经济价值的，HCHO 是一种普遍存在的空气污染物。在这里，我们比较研究了两种单原子催化剂，Na/HMO 和 Ag/HMO（HMO = 锰钙钛矿），在低温下完全氧化 HCHO 的催化性能，其产物只有 CO 和 HO。这些催化剂是通过将单个钠离子或银原子锚定在 HMO(001)表面上合成的。同步辐射 X 射线衍射图案与结构精修以及透射电子显微镜图像表明，Na/HMO 的 HMO(001)表面上的单个钠离子具有与 Ag/HMO 的银原子相同的局部结构。催化测试表明，Na/HMO 在 HCHO 的低温氧化中比 Ag/HMO 具有更高的催化活性。X 射线光电子能谱和软 X 射线吸收谱表明，Na/HMO 的表面晶格氧具有比 Ag/HMO 更高的电子密度，这是其在 HCHO 氧化中具有更高催化效率的原因。这项工作可以帮助设计廉价的碱金属催化剂，以控制挥发性有机化合物（如 HCHO）的排放。
