Mousavian Parisasadat, Esrafili Mehdi D, Sardroodi Jaber J
Department of Chemistry, Azarbaijan Shahid Madani University, Tabriz, Iran.
Department of Chemistry, Faculty of Basic Sciences, University of Maragheh, P.O. Box 55136-553, Maragheh, Iran.
J Mol Graph Model. 2022 Dec;117:108284. doi: 10.1016/j.jmgm.2022.108284. Epub 2022 Aug 12.
It is generally recognized that developing effective methods for selective oxidation of hydrocarbons to generate more useful chemicals is a major challenge for the chemical industry. In the present study, density functional theory calculations are conducted to examine the catalytic partial oxidation of methane (CH) and ethylene (CH) by nitrous oxide (NO) over Al-incorporated porphyrin-like N-doped graphene (AlN-Gr). Adsorption energies for the most stable configurations of CH, CH, and NO molecules over the AlN-Gr catalyst are determined to be -0.25, -0.64, and -0.40 eV, respectively. According to our findings, NO can be efficiently split into N and O species with a negligible activation energy on the AlN-Gr surface. Meanwhile, CH and CH molecules compete for reaction with the activated oxygen atom (O) that stays on the surface. The energy barriers for partial methane oxidation through the CH + O → CH° + HO and CH° + HO → CHOH reaction steps are 0.16 eV and 0.27 eV, respectively. Furthermore, the produced CHOH may be overoxidized by O to give formaldehyde and water molecules by overcoming a relatively low activation barrier. The activation barriers for CH epoxidation are small and comparable to those for CH oxidation, implying that AlN-Gr is highly active for both reactions. The high energy barrier for the 1,2-hydrogen shift in the OCHCH intermediate, on the other hand, makes the production of acetaldehyde impossible under normal conditions. According to the population analysis, the AlN-Gr serves as a strong electron donor to aid in the charge transfer between the Al atom and the O moiety, which is necessary for the activation of CH and CH. The findings of the present study may pave the way for a better understanding of the catalytic oxidation the CH and CH, as well as for the development of highly efficient noble-metal free catalysts for these reactions.
人们普遍认为，开发有效的烃类选择性氧化方法以生产更有用的化学品是化学工业面临的一项重大挑战。在本研究中，进行了密度泛函理论计算，以研究一氧化二氮（N₂O）在掺铝卟啉类氮掺杂石墨烯（AlN-Gr）上对甲烷（CH₄）和乙烯（C₂H₄）的催化部分氧化。确定CH₄、C₂H₄和N₂O分子在AlN-Gr催化剂上最稳定构型的吸附能分别为-0.25、-0.64和-0.40 eV。根据我们的研究结果，N₂O在AlN-Gr表面可有效分解为N和O物种，活化能可忽略不计。同时，CH₄和C₂H₄分子竞争与留在表面的活化氧原子（O）反应。通过CH₄ + O → CH₃° + OH和CH₃° + OH → CH₃OH反应步骤进行部分甲烷氧化的能垒分别为0.16 eV和0.27 eV。此外，生成的CH₃OH可能会被O进一步氧化生成甲醛和水分子，克服的活化能垒相对较低。C₂H₄环氧化的活化能垒较小，与C₂H₄氧化的活化能垒相当，这意味着AlN-Gr对这两个反应都具有高活性。另一方面，OCH₂CH中间体中1,2-氢转移的高能垒使得在正常条件下无法生成乙醛。根据布居分析，AlN-Gr作为强电子供体，有助于Al原子与O部分之间的电荷转移，这是CH₄和C₂H₄活化所必需的。本研究结果可能为更好地理解CH₄和C₂H₄的催化氧化以及开发用于这些反应的高效无贵金属催化剂铺平道路。
