Calculations of a nanographene (coronene) Ni-SAC (single atom catalyst) for hydrogenation reactions.

1Fernando Ruette, 1Yenner Bentarcurt, 2Marcos Loroño, 3Morella Sánchez, 4Andrei Tchougreeff

1Laboratory of Computational Chemistry, Chemistry Center “Dr. Gabriel Chuchani”, Venezuelan Institute of Scientific Research (IVIC), Apartado 21827, Caracas, 1020-A, Venezuela 2UNETRANS, kilometer 8, Carretera Panamericana, Caracas, Venezuela. 3Faculty of Chemistry and Engineering, Academic Department of Physical Chemistry, Office 410, University Nacional Mayor de San Marcos, Lima, Peru. 4A.N. Frumkin Institute of Physical Chemistry and Electrochemistry of RAS, Moscow, Russia.

SACs have been in the last years widely investigated in various catalytic reactions [1] because they have several advantages. (1) In SACs, the utilization of atomic active center atoms improves reactivity respect to an atomic cluster, due to its high dispersion. (2) Similar to homogeneous catalysis, SACs have the characteristics of maximum atomic utility efficiency and a well-designed catalytic center to ensure high catalytic performance. Furthermore, the interaction at the active center-support interface of SACs can be tuned by changing the electronic properties in nano-supports, leading to a catalyst with adaptive chemical reactivity. A computational study of a Ni atom in a coronene (Cor) molecule (Ni-Cor), as a model of a single-atom catalyst (SAC) with nanographene like nano-support, was carried out using a DFT. The electronic metal–support interaction (EMSI) has been used as bridge between theoretical electronic study and the design and synthesis of heterogenous catalysts. The adsorption energy results of Ni on pristine Cor are similar to those reported for extended graphene [2]. Ni-Cor adsorption is preferred at edge sites and electron transfer from Ni to Cor occurs. The location of the HOMO density in Ni-Cor determines the orientation of the H2 molecule in the coronene structure. Good correlations were obtained between the H2 activation energies and charge on Ni atom. Calculations using DFT and EH (effective Hamiltonian) shown that a substitution of a H atom of Cor by an attractor electron groups (X = O, Cl, and NO2) improved activation of the H2 molecule. Then, the interaction of ethene with those hydrogenated sites (H2-Ni-Cor-X) resulted in its hydrogenation to ethane. These theoretical findings suggest that Ni-Cor could be used for hydrogen storage because of adsorption energies (1.24-1.03 eV) and also for catalytic hydrogenation of hydrocarbons; for example, hydrogenation of olefines and CO2. References [1] A.D. Nishchakova, L.G. Bulusheva, D.A. Bulushev Supported Ni Single-Atom Catalysts: Synthesis, Structure, and Applications in Thermocatalytic Reactions, Catalysts 13 (2023) 845. https://doi.org/10.3390/catal13050845 [2] Yenner Bertancurt, Desmond Mac Leod Carey, Marcos Loroño, Morella Sánchez, Fernando Ruette, Adsorption of a Ni single atom on nanographene (coronene). A theoretical study of Ni(SAC), Chemical Physics Letters 839 (2024) 141115. https://doi.org/10.1016/j.cplett.2024.141115