A reactive force field molecular dynamics study on the inception mechanism of titanium tetraisopropoxide (TTIP) conversion to titanium clusters
A reactive force field molecular dynamics study on the inception mechanism of titanium tetraisopropoxide (TTIP) conversion to titanium clusters
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DOI：
10.1016/j.ces.2022.117496
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发表时间：
2022-02-17
影响因子：
4.7
通讯作者：
Luo, Kai H.
中科院分区：
文献类型：
--
作者：
Hou, Dingyu;Feng, Muye;Luo, Kai H.
我们进行了 ReaxFF 反应分子动力学模拟，以研究在有或没有气态 O-2 分子的情况下 TTIP 前体液滴在 1000 K-2500 K 范围内转化为含钛簇的起始机制。新的 Ti/C/H/O ReaxFF 力场已经开发出来。确定了关键的中间体钛物质和 TTIP 的初始分解途径。研究了温度、O-2 浓度和高温停留时间对 TTIP 转化为初始钛簇的影响。结果表明，由于高温下 Ti-O 键不太稳定，高热解温度并不一定会促进初始含 Ti 团簇的形成。在 TTIP 热解过程中，Ti2O CyHz 物质的出现早于 TiO2，而 TiO2 的形成早于 Ti2O CyHz 物质，并且与环境 O-2 的浓度要高得多。减少高温停留时间可促进 TiO2 蒸气的冷凝，从而促进含钛簇的形成。初始钛簇的生长模式被阐明为与 TiOCyHz 物质或钛簇形成 Ti-O 键，然后连续断裂 Ti-O 或 C-O 键以释放烃部分。 (c) 2022 Elsevier Ltd. 保留所有权利。
We performed ReaxFF reactive molecular dynamics simulations to investigate the inception mechanism of TTIP precursor droplet conversion to Ti-containing clusters in 1000 K-2500 K with or without gaseous O-2 molecules. A new Ti/C/H/O ReaxFF force field has been developed. Key intermediate titanium species and the initial decomposition pathways of TTIP are identified. The effects of temperature, O-2 concentration and high-temperature residence time on the conversion of TTIP to incipient titanium clusters are investigated. Results suggest that high pyrolysis temperature does not necessarily promote the formation of incipient Ti-containing clusters, due to less stable Ti-O bonds at high temperatures. Ti2O CyHz species appear earlier than TiO2 during TTIP pyrolysis, while TiO2 forms earlier than Ti2O CyHz species and has much higher concentration with ambient O-2. Decreasing high-temperature residence time boosts the formation of Ti-containing clusters by facilitating the condensation of TiO2 vapors. The growth pattern of the incipient titanium clusters is elucidated as formation of Ti-O bond with TiOCyHz species or titanium clusters followed by continuous breakage of Ti-O or C-O bonds to release hydrocarbon moieties. (c) 2022 Elsevier Ltd. All rights reserved.