DFT perspective of gas sensing properties of metal oxide nanocages toward trimethylamine: Effects of humidity, temperature and electric field

Developing highly efficient sensitive materials for detecting trimethylamine gas is crucial for analyzing food quality and protecting human health. In this paper, the adsorption and sensing properties of trimethylamine on pristine and doped nanocages have been analyzed based on density functional theory. The results show that Be12O12 with higher electronegativity alkaline metal atoms exhibits the shorter adsorption distance (1.75 angstrom), the larger adsorption energy (-1.39 eV) and more charge transfer (0.155 e) compared with Mg12O12 and Ca12O12, indicting Be12O12 is more sensitive toward trimethylamine gas. Fe and Zn-doped Be12O12 exhibit superior sensitivity and selectivity towards trimethylamine even in the humid environments and the presence of interfere gas (N2 and O2). Additionally, trimethylamine could be desorbed from Fe and Zn-doped Be12O12 through heating. Meanwhile, applying positive electric fields can further enhance and sensitivity of Fe and Zn-doped Be12O12 to trimethylamine. The analyses of sensitive response and recovery time reveal the potentials of Zn-doped Be12O12 as reusability resistance-type gas sensors with comparable performances. This theoretical investigation will provide valuable information for experimentalists to design and synthesis novel sensitive materials for detecting trimethylamine.