B12P12 Nanocage Doped with Transition Metals as a Single Atom Catalyst for Hydrogen Dissociation Reaction (HDR): A DFT Study

Abstract

Energy is the pivotal factor crucial for development and sustainability in every aspect of life. However, it leads to significant environmental harm when it is derived from non renewable resources like fossil fuels. This crucial issue has provoked a vigorous search for alternative energy technologies that are renewable and eco-friendly, to elevate energy efficiency and lower pollution. Hydrogen possesses high energy density, no CO2 emissions, and non-toxicity, making it a promising substitute for non-renewable energy resources. Despite its numerous advantages, there remains a challenge in choosing an appropriate material for hydrogen storage. The hydrogen dissociation reaction (HDR) is a critical step in the hydrogen storage process. HDR requires a catalyst having minimal cost and great catalytic activity. For this purpose, a promising approach in catalysis is the development of single-atom catalysts (SACs). SACs involve the uniform dispersion of a single atom on a suitable substrate. This limits metal usage and results in enhanced catalytic efficiency while lowering expenses. In this research, DFT simulations are employed to explore the adsorption and dissociation of molecular H2 on 1st row transition metal atoms incorporated into B12P12. Each TM@B12P12 complex is examined to distinguish the most stable spin state, as TM show a phenomenon named spin multiplicity. The stability of TM@B12P12 complexes is evaluated through the calculation of interaction energy. Notably, the highest interaction energy is observed for Fe@B12P12, recorded at -2.42 eV. Furthermore, NBO, FMO, IRI, and QTAIM investigations indicate that charge is transferred from B12P12 to the transition metal and validate the covalent connections within the transition metal-doped complexes. The adsorption of molecular hydrogen on the TM@B12P12 complexes has a negative adsorption energy, indicating that H₂ adsorption is exothermic. The homolytic dissociation of H₂ on the Fe@B12P12 complex exhibited the minimum energy activation ix barrier (0.44 eV), emphasizing its promise as a highly effective catalyst for the hydrogen dissociation reaction (HDR). This investigation elucidates the crucial factors that govern the electronic characteristics and catalytic efficiency of TM-doped B12P12complexes in HDR. This understanding facilitates the advancement of innovative hydrogen energy technologies.