Theoretical Study\nof Gas Sensing toward Acetone by\na Single-Atom Transition Metal (Sc, Ti, V, and Cr)-Doped InP<sub>3</sub> Monolayer

Acetone (C<sub>3</sub>H<sub>6</sub>O) gas in the exhaled\nbreath\nof diabetic patients can be used as an important biomarker for the\npainless and noninvasive diagnosis of diabetes mellitus. In this paper,\nbased on the density functional theory (DFT), the adsorption behaviors\nof pristine and single-atom transition metal (X = Sc, Ti, V, and Cr)-doped\nInP<sub>3</sub> surfaces (denoted as X-InP<sub>3</sub>) toward C<sub>3</sub>H<sub>6</sub>O molecule were examined to explore the potential\nof these two-dimensional (2D) materials as a sensitive sensor for\nacetone gas. The calculation results indicate the unfavorable detection\nproperty for the pristine 2D-InP<sub>3</sub> surface upon acetone\nwith an unsatisfied gas response (12.4%). The introduction of a single-atom\ntransition metal (Sc, Ti, V, and Cr) into the InP<sub>3</sub> layer\nhas significantly improved the adsorption capacity toward the C<sub>3</sub>H<sub>6</sub>O molecule. Owing to the high gas response values\n(−98.0%, 393.3%, and 393.3%), the Ti-InP<sub>3</sub>, V-InP<sub>3</sub>, and Cr-InP<sub>3</sub> layers show their superiority in\nC<sub>3</sub>H<sub>6</sub>O detection at room temperature, in which\nTi-InP<sub>3</sub> achieves recycle use through heating at 698 K.\nSc-InP<sub>3</sub> is unsuitable for C<sub>3</sub>H<sub>6</sub>O sensing\nwith a poor response (8.1%). Our work first gives a theoretical predication\nabout the adsorption and sensitive detection performance of pristine\nand single-atom transition metal (Sc, Ti, V, and Cr)-doped InP<sub>3</sub> upon acetone, which may provide an emerging kind of sensing\nmaterial for the noninvasive diagnosis of diabetes mellitus indicated\nby acetone gas.