Evidence of half metal to insulator transition and subsequent photocatalytic action in g-C4N3@Lin =1 to 4: A systematic theoretical analysis

Abstract

We report herein, emergence of photocatalytic action in Li doped two-dimensional nanosheet of graphitic carbon nitride [g-C4N3@Lin = 0-4]. Doping concentration varied from 3.57 % to 14.28 %. Pristine graphitic carbon nitride is half metallic and at the highest level of doping (14.28 %) it transforms into an insulating system. Observed results have been examined through the estimation of coupling between magnetic centers and the overall magnetic moment of the system. The exchange coupling (JAB) within Heisenberg–Dirac–van Vleck Hamiltonian being negative indicates antiferromagnetic coupling in presence of Li, doping. Related optical spectrum quite clearly illustrates that only at the doping level [14.28 %] the absorption peak is in the optical region. Band structure obtained illustrates a band gap of 1.92 eV and 1.93 eV in both spin channels and both oxidation and reduction potential falls within the band gap. The presence of reduction potential below the conduction band and oxidation potential above the valence band clearly illustrates the possibility of photocatalytic action.