Potential energy surfaces of adsorption and migration of transition metal atoms on nanoporus materials: The case of nanoporus bigraphene and G-C3N4

Melchakova, I (Melchakova, Iuliia)[ 1 ] ; Nikolaeva, KM (Nikolaeva, Kristina M.)[ 2 ] ; Kovaleva, EA (Kovaleva, Evgenia A.)[ 3 ] ; Tomilin, FN (Tomilin, Felix N.)[ 2,3,4 ] ; Ovchinnikov, SG (Ovchinnikov, Sergey G.)[ 2,4 ] ; Tchaikovskaya, ON (Tchaikovskaya, Olga N.)[ 3 ] ; Avramov, PV (Avramov, Pavel V.)[ 1 ] ; Kuzubov, AA (Kuzubov, Alexander A.)[ 2 ] APPLIED SURFACE SCIENCE DOI: 10.1016/j.apsusc.2020.148223

First-row transition metal (TM) atoms adsorption and migration on nanoporus 2D materials like bigraphene with double vacancies and g-C3N4 as the active sites for TM nanocluster's growth was studied within the framework of density functional theory. Both thermodynamic and kinetic aspects of composite synthesis were discussed. It was found that potential barriers of adatom's migration from bigraphene's outer surface to the interlayer space through the double vacancy are rather low values. High potential barriers of TM migration along the carbon plane prevents TM clusterization due to enhanced chemical activity of double vacancies which gives a possibility to capture the surface adatoms. As was shown for the monolayer graphene, the decrease of vacancies concentration reduces the barrier of adatom migration along the surface while the second graphene sheet in bigraphene stabilizes the structure. The behavior of TM-atom regarding g-CN2 and g-CN1 nanosheets was investigated. Potential energy surfaces were obtained and discussed. The migration barriers were found surmountable that means high probability of migration of TM adatoms to global minima and formation of TM vacancies. Comparison of barriers values with Boltzmann factor demonstrated that just standalone temperature fluctuations cannot initiate structural transitions. The properties of designed structures can be of interest of catalysts and biosensors for biomedical applications.