Tang Yanan, Chai Huadou, Chen Weiguang, Cui Xiao, Ma Yaqiang, Zhao Mingyu, Dai Xianqi
Quantum Materials Research Center, College of Physics and Electronic Engineering, Zhengzhou Normal University, Zhengzhou 450044, China.
Phys Chem Chem Phys. 2017 Oct 4;19(38):26369-26380. doi: 10.1039/c7cp05683d.
The formation geometries, electronic structures and catalytic properties of monovacancy and divacancy graphene sheets with two embedded Fe dopants (2Fe-MG and 2Fe-DG) have been systematically investigated using the first-principles calculations. It was found that the configuration of 2Fe-DG is slightly more stable than that of 2Fe-MG sheets and the two doped Fe atoms in graphene (2Fe-graphene) as active sites could regulate the stability of gas molecules. In addition, the adsorption of O and CO molecules could modulate the electronic and magnetic properties of 2Fe-graphene systems. Moreover, the adsorption behaviors of reactants could determine the reaction pathway and energy barrier of the catalytic oxidation of CO. On the 2Fe-graphene substrates, the adsorptive decomposition of O molecules (<0.20 eV) and the subsequent Eley-Rideal (ER) reaction (2O + 2CO → CO) (<0.60 eV) have low energy barriers. In comparison, the CO complex is quite stable and its formation needs to overcome a higher energy barrier (>0.90 eV). Hence, the dissociation of O as an initial step is an energetically more favored process. These results provide valuable guidance for the design of functionalized graphene-based devices.
利用第一性原理计算系统研究了含有两个嵌入铁掺杂原子的单空位和双空位石墨烯片（2Fe-MG和2Fe-DG）的结构几何、电子结构和催化性能。结果发现，2Fe-DG的构型比2Fe-MG片层略稳定，且石墨烯中作为活性位点的两个掺杂铁原子可以调节气体分子的稳定性。此外，O和CO分子的吸附可以调节2Fe-石墨烯体系的电子和磁性能。而且，反应物的吸附行为可以决定CO催化氧化的反应途径和能垒。在2Fe-石墨烯基底上，O分子的吸附分解（<0.20 eV）以及随后的埃里-里德（ER）反应（2O + 2CO → CO）（<0.60 eV）具有较低的能垒。相比之下，CO络合物相当稳定，其形成需要克服更高的能垒（>0.90 eV）。因此，O的解离作为初始步骤在能量上是更有利的过程。这些结果为功能化石墨烯基器件的设计提供了有价值的指导。
