Role of the exposure facets upon diverse morphologies of cobalt spinels on catalytic deN(2)O process
Role of the exposure facets upon diverse morphologies of cobalt spinels on catalytic deN(2)O process
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钴尖晶石不同形貌的暴露面在催化 deN(2)O 过程中的作用
DOI：
10.1016/j.cattod.2020.06.042
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发表时间：
2021
期刊：
影响因子：
5.3
通讯作者：
Ying Wei
中科院分区：
文献类型：
--
作者：
Ming Li;Runduo Zhang;Hao Wang;Hongxia Chen;Ying Wei
N_2O分解法制备了一系列不同形貌的Co_3O_4尖晶石，包括纳米立方体（NC-Co_3 O_4）、纳米片（NS-Co_3 O_4）、纳米棒（NR-Co_3 O_4）和纳米多面体（NPL-Co_3 O_4）。NC-Co_3 O_4以（0 0 1）晶面为主，比NS-Co_3 O_4和NR-Co_3 O_4以（1 1 0）晶面为主的活性高。采用N2吸附、XRD、SEM、TEM、H2-TPR、OIE、XPS等表征技术和密度泛函理论计算对其物理化学性质进行了研究。形貌和晶体条纹的研究表明，（0 0 1）晶面比（1 1 0）晶面更容易产生氧空位，其所需激活能（30 kJ mol−1）较低.在NC-Co 3 O 4的氧空位附近存在大量参与N2 O解离的表面化学吸附活性氧物种，这些活性氧物种既能促进N2 O在这些空位上的吸附，又能促进另一个N2 O分子被活性氧进一步活化。此外，NR-Co 3 O 4和NPL-Co 3 O 4催化剂的低比表面积和大颗粒尺寸限制了其催化分解N2 O的性能。
N2O decomposition has been performed on series of Co3O4spinels with various morphologies including nanocube (NC-Co3O4), nanosheet (NS-Co3O4), nanorod (NR-Co3O4) and nanopolyhedron (NPL-Co3O4). The NC-Co3O4having a predominant exposure of the (0 0 1) plane is more active than NS-Co3O4and NR-Co3O4mainly exhibiting the (1 1 0) plane. The characterization techniques such as N2sorption, XRD, SEM, TEM, H2-TPR, OIE, and XPS as well as DFT calculation are employed to investigate their physicochemical properties. The study on morphology and crystal fringe demonstrates that oxygen vacancies are more readily generated on (0 0 1) facet which requires less activation energy (30 kJ mol−1) than that for (1 1 0) facet. Abundant surface chemisorbed reactive oxygen species, involved in N2O dissociation, were existed in the vicinity of oxygen vacancies of NC-Co3O4, which could promote both N2O adsorption upon such vacancies as well as the further activation of another N2O molecule by reactive oxygen. Besides, low specific surface area and large particle size are essentially limiting the catalytic performance on N2O decomposition over NR-Co3O4and NPL-Co3O4.