Adsorption performance of TM doped (TM = Fe, Ni, Cr and Zn) silicon carbide nanotubes towards formaldehyde: a DFT-M06-L study

Abstract

In this work, the adsorption of formaldehyde (H₂CO) on the surface of transition metal-doped silicon carbide nanotubes (TM-SiCNTs; TM = Fe, Ni, Cr and Zn) were scrutinised by using M06-L meta-generalised gradient approximation (m-GGA) exchange–correlation functional. Two types of TM_Si–SiCNTs and TM_C–SiCNTs doped nanostructures were found on the potential energy surfaces. The obtained results indicate that the TM_Si–SiCNTs are more stable than TM_C–SiCNTs. The adsorption energies of H₂CO on the TM doped SiCNTs are computed to be in the range of −0.55 to −2.52 eV. The sequence of H₂CO adsorption energies on the metal-doped silicon carbide nanotubes are H₂CO-Cr_C-SiCNT > H₂CO-Fe_C-SiCNT > H₂CO-Fe_Si-SiCNT > H₂CO-Cr_Si-SiCNT > H₂CO-Ni_C-SiCNT > H₂CO-Zn_C-SiCNT > H₂CO-Ni_Si-SiCNT > H₂CO-Zn_Si-SiCNT. In comparison with the pure SiCNT, the HOMO–LUMO gap decreases and electrical conductance increases. The change in the HOMO–LUMO gap of Ni_C-SiCNT is predicted to be greater than those of others. Therefore, the Ni_C-SiCNT is predicted to be more sensitive than other metal-doped NTs to H₂CO gas. These results give new insights into the applications of TM-SiCNTs materials in H₂CO gas sensing.

GRAPHICAL ABSTRACT

KEYWORDS:

• SiCNT
• formaldehyde
• adsorption
• metal doping
• DFT

Disclosure statement

No potential conflict of interest was reported by the author(s).