Transition metal-functionalized porphyrin-like C70 fullerenes as sensors and adsorbents of formaldehyde- DFT, NBO, and QTAIM study

[Display omitted] •Transition metal- (Ti, Cr, Fe, Ni, and Zn) functionalized porphyrin C70 fullerenes (MF-PC70Fs) for sensing and removing formaldehyde were investigated using DFT, QTAIM, and NBO.•Ti- and Ni-functionalized PC70Fs were the strongest and weakest absorbents of formaldehyde.•Cr-, Fe-, and Zn-functionalized PC70Fs can be used as formaldehyde work function type sensors.•Fe- and Zn-functionalized PC70Fs are more favourite materials than Cr-functionalized in formaldehyde sensors. C70 fullerenes are effective formaldehyde sensors and adsorbents, with nitrogen or boron doping significantly increasing their sensitivity in detecting formaldehyde gas. C70 fullerenes doped with nitrogen atoms are effective in removing formaldehyde from the air. In this work, the potential of transition metal- (Ti, Cr, Fe, Ni, and Zn) functionalized porphyrin C70 fullerenes (MF-PC70Fs) for sensing and removing formaldehyde were investigated using DFT, QTAIM, and NBO. The HOMO-LUMO gaps for Ti, Cr, Fe, Ni, and Zn-functionalized materials were computed, resulting in values of 1.27, 0.07, 1.84, 1.84, and 1.80 eV, respectively. The absorption energies of formaldehyde onto MF-PC70Fs were computed, revealing that the PC70Fs functionalized with Ti had the highest adsorption strength, while those functionalized with Ni had the lowest. The HOMO-LUMO gap of Cr- and Fe-functionalized PC70Fs was significantly changed after adsorbing formaldehyde. Accordingly, they may be used as conductivity-type sensors for detecting formaldehyde. Also, Cr-, Fe-, and Zn-functionalized PC70Fs can be used as formaldehyde work function type sensors. According to the calculated time recovery of MF-PC70Fs, Fe- and Zn-functionalized PC70Fs are more favourite materials than Cr-functionalized in formaldehyde sensors.