摘要：To study the substituent effects of 4,6-dimethyl-dibenzothiophene (4,6-DMDBT) on the direct hydrodesulfurization (DDS) routes catalyzed on a Ni-Mo-S nanocluster, a non-periodic computational Ni-Mo-S model is established, and density functional theory (DFT) is used to comparatively calculate the adsorption and the conversion of the dibenzothiophene (DBT) and 4,6-DMDBT on the Ni-S-edge, Ni-Mo-edge and corner sites of the Ni-Mo-S active nanocluster. The calculation results show that on the Ni-Mo-S active nanocluster, the Ni-S-edge could stably provide active hydrogen, whereas the C–S bond cleavage on this active site required higher activation energy. The Ni-Mo-edge could not stably provide active hydrogen, and this active site has the highest activity of C–S bond cleavage. The corner site shows favorable ability of hydrogen activation and C–S bond cleavage. The methyl group of 4,6-DMDBT weakens the Ni–S bonds caused by the adsorption on the Ni-S-edge, where the decrease of the adsorption energy is compensated by an additional dispersion provided by two methyl groups. The two methyl groups also decrease the adsorption angle between the 4,6-DMDBT and the CUS sites on the Ni-Mo-edge and corner sites. The flat adsorption of 4,6-DMDBT will further hinder the hydrogen activation and transfer on the Ni-Mo-edge. Moreover, the methyl group of 4,6-DMDBT decreases the energy difference between the reactant and the intermediate of the DDS route, increasing the reaction energy of the C–S bond cleavage. The dominant DDS route of the DBT and 4,6-DMDBT involves the interaction between active hydrogen and the α-C followed by the movement of the newly formed aromatic ring away from the S atom of the sulfur compounds. During this process, the methyl groups of the 4,6-DMDBT will hinder the C–S bond cleavage on all CUS sites on the Ni-S-edge, Ni-Mo-edge and corner sites of the Ni-Mo-S nanocluster. Therefore, the activation energy of the C–S bond cleavage of 4,6-DMDBT is higher than that of DBT, and this is the main reason for the lower DDS rate of the former compared to the latter.
© 2017 Elsevier B.V.

ISSN号：0920-5861

卷、期、页：v 305,p28-39

发表日期：2018-05-01

影响因子：0.000000

收录情况：SCI（科学引文索引印刷版）,ESI（基本科学指标数据库）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：Catalysis Today

通讯作者：丁思佳,蒋淑娇,周文武

第一作者：周亚松,魏强

论文类型：期刊论文

论文概要：丁思佳,周亚松,魏强,蒋淑娇,周文武，Substituent effects of 4,6-DMDBT on direct hydrodesulfurization routes catalyzed by Ni-Mo-S active nanocluster—A theoretical study，Catalysis Today，2018，v 305,p28-39

论文题目：Substituent effects of 4,6-DMDBT on direct hydrodesulfurization routes catalyzed by Ni-Mo-S active nanocluster—A theoretical study