金属原子修饰石墨烯体系催化性能的理论研究

采用基于密度泛函理论的第一性原理方法研究了单个CO和O2气体分子在金属原子修饰石墨烯表面的吸附和反应过程.结果表明:空位缺陷结构的石墨烯能够提高金属原子的稳定性,金属原子掺杂的石墨烯体系能够调控气体分子的吸附特性.通入混合的CO和O2作为反应气体,石墨烯表面容易被吸附性更强的O2分子占据,进而防止催化剂的CO中毒.此外,对比分析两种催化机理(Langmuir-Hinshelwood和Eley-Rideal)对CO氧化反应的影响.与其它金属原子相比,Al原子掺杂的石墨烯体系具有极低的反应势垒(0.4 e V),更有助于CO氧化反应的迅速进行.

Theoretical Study on Catalytic Property of Metallic Atom-Decorated Graphene Sheets

In this work, the adsorption and reactions of single CO and O2 on metal atom (MA) decorated graphene (MA-graphene) were studied using the first-principle calculations based density functional theory. The study shows that a vacancy defect in graphene can improve the stability of metal atoms, and the formed MA-graphene systems would modulate the adsorption properties of gas molecules. The MA-graphene surfaces prefer to cover by the adsorbed O2 if CO and O2 mixture is injected as the reaction gas, and thus prevent the CO poisoning of metal catalysts. Besides, the two reaction mechanisms (including Langmuir-Hinshelwood and Eley-Rideal) for the CO oxidation are investigated for comparison. In contrast to other metal atoms, the CO oxidation reactions are more likely to proceed on the Al embedded graphene surface due to the lower energy barriers (< 0.4 eV).