Theoretical Study of Gas Sensing toward Acetone by a Single-Atom Transition Metal (Sc, Ti, V, and Cr)-Doped InP₃ Monolayer

Acetone (C₃H₆O) gas in the exhaled breath of diabetic patients can be used as an important biomarker for the painless and noninvasive diagnosis of diabetes mellitus. In this paper, based on the density functional theory (DFT), the adsorption behaviors of pristine and single-atom transition metal (X = Sc, Ti, V, and Cr)-doped InP₃ surfaces (denoted as X-InP₃) toward C₃H₆O molecule were examined to explore the potential of these two-dimensional (2D) materials as a sensitive sensor for acetone gas. The calculation results indicate the unfavorable detection property for the pristine 2D-InP₃ surface upon acetone with an unsatisfied gas response (12.4%). The introduction of a single-atom transition metal (Sc, Ti, V, and Cr) into the InP₃ layer has significantly improved the adsorption capacity toward the C₃H₆O molecule. Owing to the high gas response values (-98.0%, 393.3%, and 393.3%), the Ti-InP₃, V-InP₃, and Cr-InP₃ layers show their superiority in C₃H₆O detection at room temperature, in which Ti-InP₃ achieves recycle use through heating at 698 K. Sc-InP₃ is unsuitable for C₃H₆O sensing with a poor response (8.1%). Our work first gives a theoretical predication about the adsorption and sensitive detection performance of pristine and single-atom transition metal (Sc, Ti, V, and Cr)-doped InP₃ upon acetone, which may provide an emerging kind of sensing material for the noninvasive diagnosis of diabetes mellitus indicated by acetone gas.