NiN4S-doped single walled carbon nanotube as an ultrafast H2 gas sensor: A DFT simulation

Here, the capability of NiN4S-doped single wall carbon nanotube (NiN4S-doped SWCNT) as a sensor material for detection of H2 gas at room temperature has been studied and compared with pristine single wall carbon nanotube (SWCNT). The coB97XD method with 6-311++G(d,p) and LanL2DZ basis sets have been used for all opt/freq calculations. The initial calculations demonstrated that the H2 molecule does not show any effective adsorption on the pristine SWCNT (Ead =-0.17 kcal.mol-1 and q approximate to 0 e). However, doping SWCNT with NiN4S changed the results. The Ead and q values were improved for adsorption of H2 on NiN4S-doped SWCNT to-1.89 kcal.mol-1 and 0.001 e, respectively. The Eg value of the NiN4S-doped SWCNT decreased from 2.40 eV to 1.59 eV upon H2 adsorption and therefore the electrical conductivity of adsorbent increased which can be converted to an electronic signal. In order to better evaluate the nature of H2...NiN4S-doped SWCNT interaction, the variety analyses such as atom in molecules (AIM), non-covalent interaction-reduced electron density gradient (NCI-RDG), electron density (ED) and electron localization function (ELF) were performed. The results confirmed that the adsorption performed via a typical van der Waals interactions. Consequently, NiN4S-doped SWCNT can be introduced as an ultrafast and efficient material for H2 sensing with-1.89 kcal.mol-1 adsorption energy,-50.94% Delta Eg and only 22 ps recovery time.

Automated summary

In this study, the capability of NiN4S-doped single wall carbon nanotube (NiN4S-doped SWCNT) as a sensor material for detecting H2 gas at room temperature was investigated and compared with pristine single wall carbon nanotube (SWCNT). The results showed that the adsorption capacity of H2 on NiN4S-doped SWCNT was significantly improved compared to pristine SWCNT. It was found that the adsorption occurred via typical van der Waals interactions. Therefore, NiN4S-doped SWCNT can be considered as an ultrafast and efficient material for H2 sensing.