Magnetization effect of Mn-embedded in C₂N on hydrogen adsorption and gas-sensing properties: Ab-initio analysis

Density functional theory (DFT) has been employed to investigate the effect of magnetic moment on the hydrogen adsorption and gas-sensing properties in Mn-embedded in C₂N. Special focus was given to the effects of both magnetization and dimerization on the adsorption properties. Two distinct configurations of embedment were considered: (i) Single atom catalyst (SAC): 1Mn@C₂N; and (ii) Dimer atom Catalyst (DAC): Mn₂@C₂N. The results showed that the H₂ molecule to exhibit chemisorption processes on both SAC and DAC with weak molecular dissociation. The effect of chemisorption on the electronic structure is so enormous to the extent that the DOS got fragmented near Fermi level with opening of small gaps of order 0.11 eV and 0.20 eV in SAC and DAC, respectively. Such changes would be manifested in enhanced sensor responses. Based upon the huge changes in electronic and magnetic properties induced by the chemisorption and the low recovery time (i.e., τ ≪ 1 s, τ = 92 μs and 1.8 ms, respectively), we concluded that C₂N:Mn should be an excellent candidate for (reusable) hydrogen magnetic gas sensor with high sensitivity and selectivity and rapid recovery time. Our theoretical results were corroborated with good agreement with the available data in literature.