College of Environment, Zhejiang University of Technology, 18 Chaowang RD, Hangzhou, 310014, PR China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing, 100084, PR China.
College of Environment, Zhejiang University of Technology, 18 Chaowang RD, Hangzhou, 310014, PR China.
Chemosphere. 2023 Sep;336:139130. doi: 10.1016/j.chemosphere.2023.139130. Epub 2023 Jun 5.
A series of CeO-MnO for highly efficient catalytical oxidation of carbon monoxide were prepared by citrate sol-gel (C), hydrothermal (H) and hydrothermal-citrate complexation (CH) methods. The outcome indicates that the catalyst generated using the CH technique (CH-1:8) demonstrated the greatest catalytic performance for CO oxidation with a T of 98 °C, and also good stability in 1400 min. Compared to the catalysts prepared by C and H method, CH-1:8 has the highest specific surface of 156.1 m g, and the better reducibility of CH-1:8 was also observed in CO-TPR. It is also observed the high ratio of adsorbed oxygen/lattice oxygen (1.5) in the XPS result. Moreover, characterizations by the TOF-SIMS method indicated that obtained catalyst CH-Ce/Mn = 1:8 had stronger interactions between Ce and Mn oxides, and the redox cycle of Mn+Ce ↔ Mn+Ce was a key process for CO adsorption and oxidation process. According to in-situ FTIR, the possible reaction pathway for CO was deduced in three ways. CO directly oxidize with O to CO, CO adsorbed on Mn and Ce reacts with O to form intermediates (COO) (T > 50 °C) and carbonates (T > 90 °C), which are further oxidized into CO.
采用柠檬酸溶胶-凝胶法（C）、水热法（H）和水热-柠檬酸络合法（CH）制备了一系列用于高效催化氧化一氧化碳的 CeO-MnO。结果表明，采用 CH 技术制备的催化剂（CH-1:8）在 CO 氧化中表现出最佳的催化性能，T98°C，在 1400min 内也具有良好的稳定性。与 C 和 H 方法制备的催化剂相比，CH-1:8 具有最高的比表面积 156.1m²/g，并且在 CO-TPR 中也观察到 CH-1:8 的更好的还原性能。XPS 结果还观察到高的吸附氧/晶格氧比（1.5）。此外，通过 TOF-SIMS 方法的表征表明，所获得的催化剂 CH-Ce/Mn=1:8 具有 Ce 和 Mn 氧化物之间更强的相互作用，Mn+Ce ↔ Mn+Ce 的氧化还原循环是 CO 吸附和氧化过程的关键过程。根据原位 FTIR，推断出 CO 可能有三种反应途径。CO 直接与 O 氧化成 CO，CO 吸附在 Mn 和 Ce 上与 O 反应形成中间体（COO）（T>50°C）和碳酸盐（T>90°C），然后进一步氧化成 CO。
