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

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 TMSi-SiCNTs and TMC-SiCNTs doped nanostructures were found on the potential energy surfaces. The obtained results indicate that the TMSi-SiCNTs are more stable than TMC-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.

Automated summary

The adsorption of formaldehyde on transition metal-doped silicon carbide nanotubes was analyzed, revealing that TMSi-SiCNTs are more stable than TMC-SiCNTs and the adsorption energies of H2CO on the metal-doped SiCNTs follow a specific sequence. The study provides new insights into the applications of TM-SiCNTs materials in formaldehyde gas sensing.