Size-Dependent Activity of Iron Nanoparticles in Both Thermal and Plasma Driven Catalytic Ammonia Decomposition
Size-Dependent Activity of Iron Nanoparticles in Both Thermal and Plasma Driven Catalytic Ammonia Decomposition
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DOI：
10.1021/acs.iecr.2c02092
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发表时间：
2022-08-10
影响因子：
4.2
通讯作者：
Xiang, Yizhi
中科院分区：
文献类型：
--
作者：
Chen, Genwei;Qu, Jing;Xiang, Yizhi
采用多元醇法制备了直径分别为4.2 +/- 0.6、6.1 +/- 0.8、8.1 +/- 1和10.4 +/- 1 nm的水分散Fe(3)O(4)纳米颗粒，并将其作为Fe3O4/Al2O3催化剂的前驱体，研究了其粒径相关活性。我们发现，催化剂在NH3分解中的活性（由热和介质阻挡放电等离子体驱动）随着Fe3O4粒径的增加而增加。在热催化分解过程中，Fe3O4前驱体尺寸从4.2 nm增加到10.4 nm，转换频率（TOFs）从0.9 s-1增加到5.8 s-1。在等离子体催化分解中也观察到非常相似的“粒径效应”，尽管观察到较低的TOF。此外，在催化分解的早期阶段发现了反应诱导的催化剂重构，这可归因于FeOx向fen的氮化作用。我们的结果为催化NH3分解的“结构敏感性”提供了新的证据。
Water-dispersible Fe(3)O(4 )nanoparticles with diame-ters of 4.2 +/- 0.6, 6.1 +/- 0.8, 8.1 +/- 1, and 10.4 +/- 1 nm were prepared through the polyol method and employed as the precursors of Fe3O4/Al2O3 catalysts to study the size-dependent activity. We identified that the activity of the catalysts in NH3 decomposition (driven by both thermal and dielectric barrier discharge plasma) increased with increasing Fe3O4 particle size. The turnover frequencies (TOFs) were increased from 0.9 to 5.8 s-1 with an increasing Fe3O4 precursor size from 4.2 to 10.4 nm during the thermocatalytic decomposition. A quite similar "particle size effect " was also observed for the plasma catalytic decomposition, although lower TOF was observed. Additionally, reaction-induced catalyst reconstruction was identified during the early-stage of the catalytic decomposition and can be attributed to the nitridation of FeOx to FexN. Our results provide new evidence for the "structure-sensitivity " of the catalytic NH3 decomposition.