五边形石墨烯负载Pt单原子稳定性能的应变调控

Investigation on strain effects on stability of Pt single atoms supported on pentagonal graphene

基于密度泛函理论的第一性原理计算方法,研究了Pt原子在五边形石墨烯(PG)上的吸附与动力学行为.研究结果表明,单个Pt原子在PG上虽然具有较大的吸附能及较高的扩散势垒,却不能够在衬底形成均匀分散的单原子.这是因为,随Pt原子数增加,Pt_(n)(n=1,2,3)在PG上的平均结合能也逐渐增加,更倾向于形成团簇,该发现有效否定了之前的报道称Pt能在PG上形成稳定的单原子催化剂这一结论(Phys.Chem.Chem.Phys.21,12201(2019)).基于此,我们考虑对PG施加双轴应变,随着拉伸应力增加,Pt金属原子间的平均结合能逐渐降低,当拉伸应变施加至12%左右时,单个Pt在衬底上的结合能与Pt_(2)在衬底上的平均结合能相等,从而实现PG上均匀分散的Pt单原子催化剂.该结果对五边形石墨烯基材料应变调控实现单原子催化剂提供理论借鉴.

Based on the first-principles calculations of density functional theory,we investigate the adsorption and kinetic behaviors of Pt atoms on pentagonal graphene(PG).Results show that although Pt atom has a large adsorption energy and a high diffusion barrier on PG,it cannot form atomically dispersed single-atom catalyst(SAC)on the substrate.This is because,with the increase of the number of Pt atoms,the average binding energy of Pt_(n)(n=1,2,3)on the substrate also gradually increases,so it is more inclined to form clusters.This finding effectively denies the previous report that stable Pt SAC on PG.Based on this,we apply biaxial strain to PG to modulate the stability of Pt SAC.As the tensile strain increases,the average binding energy for Pt_(n)(n=1,2,3)gradually decreases.When the tensile strain is about 12%,the real atomically dispersed Pt SAC is realized.The results provide a theoretical guidance for strain engineering to achieve stable SAC in the PG-based systems.