Computational Modeling of Various Nanomaterials for Electrocatalytic Energy Applications

Current research in materials science encompasses either production or storage of renewable energy or development of green research protocols. In this respect, I shall discuss computational modeling of several nanomaterials for electrocatalytic reactions, namely, bifunctional electrocatalysts and water splitting cathodic reaction, i.e. oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER). I shall discuss the bifunctional electrocatalytic activity of transition metal (Co/Rh/Ir) and N co-doped graphene (G) system with varying N concentrations using first principles calculations. The TM-N₄@G systems are found to be highly efficient bifunctional electrocatalysts and we find DG_OH* to be a good descriptor in designing superior bifunctional electrocatalysts [1]. I shall also talk on the bifunctional electrocatalytic reactions in a Co-pyrophosphate, where we find that the bifunctional activity is rooted in the Co active site with CoO₅ local coordination in the (110) surface and the bulk oxygen makes way for the intermediate to bind with Co to give rise to superior overpotential values for both oxidation and reduction reactions [2].<br/>For electrocatalytic HER in acidic media, I shall discuss the SiPF-tetrazine covalent organic framework (COF) which exhibits superior HER catalytic activity with DG_H*values being almost zero [3]. The superior HER activity found in two nanoclusters, namely, Ni₇₃Mo alloy electro-deposited on Cu nanowires and Ni₅Mo-hydroxide on Ni foam will be discussed [4-5]. In both the cases, through DFT calculations, we find that there is an unorthodox intra-lattice ‘inverse’ charge transfer from Mo to Ni. In fact, the undercoordinated Mo-centre pushes the Mo 4d-orbitals closer to the Fermi level in the valence band region while Ni 3d-orbitals lie in the conduction band facilitating the inverse charge transfer from the electron-rich Mo-centre to the electron-poor Ni-centre. I shall also discuss the all-pH HER electrocatalytic activity found in an interconnected NiV-LDH - CoP nanowire heterostructure. From our DFT calculations through Bader charge analysis, we find the higher concentration of charge carriers at the heterointerface and the transfer of fractional electronic charge from the hole-enriched NiV-LDH to the electron rich CoP surface at the heterointerface [6]. The stability of the hosts, surface types, selectivity, detailed mechanism, d-orbital centre, overpotential values and many other quantities relevant for the robust prediction and explanation of experimental data in each of these systems will be discussed.<br/>References:<br/>1. S. Dutta, P. Banerjee, S. K Pati, ACS Phys. Chem. Au <b>2</b>, 305 (2022).<br/>2. S. Dutta, S. K Pati, Cat. Lett. <b>152</b>, 3548 (2022).<br/>3. K. Sada, R. Gond, N. Bothra, S. K Pati, P. Barpanda, ACS App. Mater. Inter. <b>14</b>, 8992 (2022).<br/>4. S Parvin, N. Bothra, S. Dutta, M. Maji, M. Mura, A. Kumar, D. K. Chaudhary, P. Rajput, M. Kumar, S. K Pati, S. Bhattacharyya, Chem. Sc. <b>14</b>, 3056 (2023).<br/>5.M. Maji, S. Dutta, R. Jena, A. Dey, T. K. Maji, S. K Pati, S. Bhattacharyya, Angew. Chem. Int. Ed. (2024). https://doi.org/10.1002/anie.202403697<br/>6. M. Maji, N. Dihingia, S. Dutta, S. Parvin, S. K Pati, S. Bhattacharyya, J. Mater. Chem. <b>A 10</b>, 24927 (2022)