Effects of Ir and B co-doping on H2 adsorption properties of armchair carbon nanotubes using Optical Spectra Analysis for energy storage

Abstract

In this research, DFT+U approach was used to investigate the performance of Iridium (Ir) and Boron (B) co-doped armchair (8, 8) Single-walled Carbon Nanotube (SWCNT). Calculations of the structural electronic and optical spectra analysis of the system under study were carried out using the ab’initio quantum simulations implemented in Quantum ESPRESSO and thermo_pw codes within the popular density functional theory. In the doping process, carbon atoms have been replaced by Ir and B atoms in the SWCNT, the investigations were done on the basis of distance of H2 (d) from the co-doped SWCNT at intervals of 6.12 Å, 6.45 Å and 6.77Å, variations of temperature, variations of external electric field, band gaps, optical adsorptions and binding energy variations were all taken in to account. It is found that Ir/B co-doping in pristine SWCNT significantly enhanced the H2 adsorption capacity of the SWCNT. Furthermore, an increase in temperature decrease the performance ability of the co-doped SWCNT, negative adsorptions intensities were recorded by temperature increase by 650, 700 and 750 0C, this can be termed as exothermic adsorption. Therefore it can be demonstrated that H2 by co-doped SWCNT undergoes endothermic adsorption under ambient temperature and shows exothermic adsorption under higher temperatures.