Thermodynamic Barrier to Nucleation for Manganese Oxide Nanoparticles Synthesized by High-Temperature Gas-to-Particle Conversion
Thermodynamic Barrier to Nucleation for Manganese Oxide Nanoparticles Synthesized by High-Temperature Gas-to-Particle Conversion
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DOI：
10.1021/acs.energyfuels.0c03662
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发表时间：
2021-01-11
期刊：
影响因子：
5.3
通讯作者：
Camacho, Joaquin
中科院分区：
文献类型：
--
作者：
Dasappa, Shruthi;Camacho, Joaquin
本文对预混滞止火焰中纳米氧化锰的成核进行了补充的实验和模拟研究。目前的合成是在较高的火焰温度和较低的前驱体负载量下进行的。基于假定的成核过程--Mn(G)+O-2(G)->；MnO(S)，进行了热力学分析，以量化前体过饱和度和开尔文效应对颗粒形成的潜在影响。基于计算的火焰后区温度-时间-氧气历史，分析了形核和生长过程。基础火焰和前体掺杂火焰的火焰位置的实测值和计算值之间的一致性表明，在目前研究的条件下，甲基环戊二烯基锰前驱体并不抑制火焰化学。由迁移率、颗粒大小测定和透射电子显微镜图像测量的颗粒尺寸分布显示出合理的一致性。此外，通过成核限制机制而不是通过凝聚限制生长预测的大小，可以更准确地预测测量的颗粒大小。
A complementary experimental and modeling study is reported here for nucleation of manganese oxide nanoparticles in premixed stagnation flames. The current synthesis occurs at relatively high flame temperature and low precursor loading. Thermodynamic analysis based on the postulated nucleation process, Mn(g) + O-2(g) -> MnO(s), is carried out to quantify precursor supersaturation and potential impacts of the Kelvin effect on particle formation. Nucleation and growth are analyzed based on the computed temperature-time-oxygen history in the postflame region. Agreement between measured and computed flame position for the base flame and precursor doped flames indicates that the manganese methylcyclopentadienyl tricarbonyl precursor does not inhibit flame chemistry for the conditions currently studied. Particle size distributions measured by mobility particle sizing and TEM images show reasonable agreement. Moreover, the measured particle size is predicted much more closely by a nucleation-limited mechanism rather than the size predicted by coagulation-limited growth.