C_(24)N_(24)负载Sc单原子催化剂催化甲烷氧化为甲醇的理论计算  

Theoretical calculation of catalytic oxidation of methane to methanol over C_(24)N_(24)supported Sc single-atom catalyst

作　　者：汪曼 王军凯 黄珍霞 葛英豪 黄起焓 WANG Man;WANG Jun-Kai;HUANG Zhen-Xia;Ge Ying-Hao;Huang Qi-Han(School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;School of Chemistry and Chemical Engineering,Henan Polytechnic University,Jiaozuo 454003,China)

机构地区：[1]河南理工大学材料科学与工程学院,焦作454003 [2]河南理工大学化学化工学院,焦作454003

出　　处：《原子与分子物理学报》2023年第4期17-22,共6页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(52102017);河南省科技攻关计划(212102210589);河南省博士后项目启动资助(2020SZZ02);河南理工大学博士基金(B2019-40);河南省高校基本科研业务费专项资金资助(NSFRF220410)。

摘　　要：甲醇是一种很有前途的清洁能源,有望替代不可再生的石油能源.因此,将储量巨大,但不易运输的甲烷氧化为甲醇具有十分重要的意义.首先通过密度泛函理论(density functional theory,DFT)计算研究了Sc原子与C_(24)N_(24)之间的稳定性.结果表明,Sc原子与C_(24)N_(24)的结合能(-9.064 eV)小于Sc原子的内聚能(-4.518 eV),即Sc@C_(24)N_(24)具有良好的稳定性.在此基础上,进一步研究了甲烷在Sc@C_(24)N_(24)表面催化氧化制备甲醇的工艺过程,以N_(2)O为氧化剂在Sc@C_(24)N_(24)单原子上进行甲醇的催化氧化反应.结果表明:N_(2)O首先吸附在Sc@C_(24)N_(24)上,然后直接分解为N_(2)和O ads.N_(2)被释放,只有O ads被吸附于Sc@C_(24)N_(24)作为活性氧,用于后续催化甲烷氧化制甲醇过程.甲烷的氧化过程包括两个步骤:(1)CH_(4)+O ads→CH_(3)*+OH*,反应势垒为0.43 eV;)CH_(3)*+OH*→CH_(3)OH,反应势垒为0.63 eV.最后,生成的CH_(3)OH分子将离开Sc@C_(24)N_(24)单原子催化剂表面,这一步所需的能量分别为1.29 eV.这些发现为甲醇的催化氧化反应提供了理论指导,Sc@C_(24)N_(24)有望成为催化甲烷制备甲醇的高效单原子催化剂.Methanol is a promising source that can replace non-renewable petroleum energy.Therefore,it is of great significance to oxidize the methane into methanol because methane is not easy to transport although its huge reserves.The stability between Sc atoms and C_(24)N_(24)is firstly studied through density functional theory(DFT)calculations.The results show that the binding energy between Sc and C_(24)N_(24)(-9.064 eV)is more negative than the cohesive energy of Sc atoms(-4.518 eV),indicating that Sc@C_(24)N_(24)possesses good stability.On this basis,the oxidation process of methane to methanol is further studied on the Sc@C_(24)N_(24)single-atom catalysis using N_(2)O as the oxidant.The results show that N_(2)O is firstly adsorbed on Sc@C_(24)N_(24)and then directly decomposed into N_(2)and O ads.N_(2)is released and only O ads is adsorbed on C_(24)N_(24)as active oxygen for the following catalytic oxidation process of methane to methanol.The process includes two steps:1)CH_(4)+O ads→CH_(3)*+OH*,the reaction barrier in this process is 0.43 eV;2)CH_(3)*+OH*→CH_(3)OH,the reaction barrier is 0.63 eV in this step.Finally,the obtained CH_(3)OH molecule will leave the surface of Sc@C_(24)N_(24)single atom catalyst and the energy required for this step is 1.29 eV.These findings provide theoretical guidance for the catalytic oxidation of methanol,and Sc@C_(24)N_(24)is expected to be a highly efficient monatomic catalyst for catalytic methane to methanol.

关 键 词：甲烷氧化 C_(24)N_(24)富勒烯 DFT 单原子催化剂 

分 类 号：TQ223[化学工程—有机化工]