DFT Studies on the Interaction of Defective Graphene-Supported Fe and Al Nanoparticles

The structural, electronic, and magnetic properties of Fe-13 and A(13) nanoparticles adsorbed on monovacancy defective graphene have been determined using density functional theory with the generalized gradient approximation (GGA). Graphene vacancies are used as anchoring points for these pure metal nanoparticles, ensuring their isolated stability on the surface, thereby maximizing their catalytic reactivity through the availability of undercoordinated surface sites along with a high surface area. The results of this work indicate that the strong binding of Fe-13 and Al-13 nanoparticles on defective graphene (-6.98 and -3.84 eV in adsorption energy, respectively) is due to strong hybridization of the nanoparticles with the sp(2) dangling bonds of neighboring carbons near the vacancy. Charge difference and Bader charge analyses of the Fe-13 and Al-13 adsorbed systems suggest that charge redistribution of defective graphene occurs to a greater extent in the Fe-13 system than in the Al-13 system due to the strongly hybridized Fe-13 d-states with the monovacancy defective site of graphene. For the Fe-13 nanoparticle, upon adsorption its d-band center shifts closer to the Fermi level from -1.28 to -1.13 eV, indicating a potential increase in the catalytic reactivity associated with the graphene surface.