Fe元素及点缺陷对焦炭表面NH_3异相吸附的影响:密度泛函理论研究  

Effect of Fe and point deficiency on adsorption behavior of NH_3 on coke surface: A density functional theory study

作　　者：李焕龙[1,2] 金晶 侯封校[1,2] 王永贞 翟中媛 赵冰[1,2] LI Huan-long;JIN Jing;HOU Feng-xiao;WANG Yong-zhen;ZHAI Zhong-yuan;ZHAO Bing(Department of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Collaborative Innovation Research Institute,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]上海理工大学协同创新研究院,上海200093

出　　处：《燃料化学学报》2018年第12期1505-1512,共8页Journal of Fuel Chemistry and Technology

基　　金：十三五国家科技支撑项目(2017YFF0209800)资助~~

摘　　要：采用密度泛函理论,并使用具有周期性边界条件的石墨烯模型近似模拟焦炭表面,研究了Fe原子修饰及点缺陷对NH_3在焦炭表面异相吸附的影响。计算结果表明,NH_3分子在点缺陷石墨烯表面的吸附属于物理吸附,结合能为-0.381 e V;NH_3分子吸附在Fe修饰的完整石墨烯表面属于化学吸附,吸附能为-1.442 eV; Fe原子修饰及点缺陷单独存在下NH_3的吸附能均大于NH_3在完整石墨烯表面的吸附(吸附能为-0.190 eV)。此外,Fe原子修饰与点缺陷共存对NH_3的吸附具有协同作用,结合能达到-3.538 eV,明显大于两者单独存在下NH_3的吸附能之和,综合分析Mulliken布居数与态密度,Fe原子与石墨烯表面、NH_3分子之间有更多地电荷转移,可以解释两者共存对NH_3吸附协同促进的原因。Effect of Fe and point deficiency on adsorption behavior of NH 3 on coke surface was studied using density functional theory and graphene model with periodic boundary conditions.The results show that the adsorption of NH 3 on surface of point-defective graphene belongs to physical adsorption with binding energy of-0.381 eV.The adsorption of NH 3 on surface of Fe-modified-graphene belongs to chemical adsorption with energy of-1.442 eV.The adsorption energy of NH 3 in the presence of Fe atom or point defect is greater than that of NH 3 on the surface of intact graphene.In addition,coexistence of Fe atom and point defect has a synergistic effect on adsorption of NH 3 with binding energy of-3.538 eV,which is much higher than the sum of adsorption energy of NH 3 in the presence of the two alone.There is more charge transferring among Fe atom,graphene surface and NH 3 molecule,which can explain the synergistic effect of coexistence of Fe and point defect.

关 键 词：密度泛函理论 焦炭 NH3 Fe 点缺陷 吸附 

分 类 号：TK16[动力工程及工程热物理—热能工程]