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<p>Fe-doped graphyne (Fe–GY), defined here as an H<sub>1</sub>-like hollow-site Fe-doped <i>γ</i>-graphyne single-atom model, is a promising 2D carbon platform for chemiresistive gas sensing because transition-metal dopants can introduce chemically active sites while the conjugated carbon network provides an efficient charge-transport channel. Herein, density functional theory calculations were performed to elucidate the adsorption behavior and electronic-response mechanism of Fe–GY toward three representative volatile organic compounds (VOCs), namely formaldehyde (HCHO), acetone (CH<sub>3</sub>COCH<sub>3</sub>), and benzene. The computed adsorption energies indicate strong binding for oxygenated VOCs (HCHO: −&#xa0;1.349&#xa0;eV; acetone: −&#xa0;0.948&#xa0;eV) and moderate binding for benzene (−&#xa0;0.528&#xa0;eV). Examination of atmospheric species shows that O<sub>2</sub> binds appreciably to the Fe site (−&#xa0;0.881&#xa0;eV), while H<sub>2</sub>O also shows moderate interaction (−&#xa0;0.377&#xa0;eV), indicating that these species may compete for active sites under ambient conditions rather than being negligible interferents. Charge analysis reveals pronounced interfacial charge redistribution for HCHO and acetone, whereas benzene shows nearly negligible net charge transfer, consistent with distinct interaction natures. HLE17 electronic-structure calculations further demonstrate that adsorption induces substantial band-edge modulation: the nearly gapless Fe–GY substrate (0.007&#xa0;eV) develops opened gaps upon VOC adsorption (0.192, 0.362, and 0.392&#xa0;eV for HCHO, acetone, and benzene, respectively). Additional orbital analyses indicate that the benzene-induced gap opening arises from functional-sensitive adsorbate–substrate frontier-level alignment rather than strong charge-transfer-driven orbital hybridization. Together with PDOS, OPDOS/COOP, charge-density-difference, IGMH, magnetic-moment, and AIMD analyses, these results provide a more cautious mechanistic picture linking adsorption energetics, spin-dependent electronic perturbation, and sensing-relevant electronic response, highlighting Fe–GY as a viable candidate platform for VOC adsorption while emphasizing the need to consider O<sub>2</sub> competition under realistic atmospheres.</p>

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First-principles investigation of Fe-doped graphyne as VOCs sensor: upon adsorption of formaldehyde, acetone and benzene

  • 期刊论文

  • 发表日期：

    2026年6月22日

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  • Yukun Han,
  • Wanying He,
  • Xiaojie Zhang

摘要

Fe-doped graphyne (Fe–GY), defined here as an H1-like hollow-site Fe-doped γ-graphyne single-atom model, is a promising 2D carbon platform for chemiresistive gas sensing because transition-metal dopants can introduce chemically active sites while the conjugated carbon network provides an efficient charge-transport channel. Herein, density functional theory calculations were performed to elucidate the adsorption behavior and electronic-response mechanism of Fe–GY toward three representative volatile organic compounds (VOCs), namely formaldehyde (HCHO), acetone (CH3COCH3), and benzene. The computed adsorption energies indicate strong binding for oxygenated VOCs (HCHO: − 1.349 eV; acetone: − 0.948 eV) and moderate binding for benzene (− 0.528 eV). Examination of atmospheric species shows that O2 binds appreciably to the Fe site (− 0.881 eV), while H2O also shows moderate interaction (− 0.377 eV), indicating that these species may compete for active sites under ambient conditions rather than being negligible interferents. Charge analysis reveals pronounced interfacial charge redistribution for HCHO and acetone, whereas benzene shows nearly negligible net charge transfer, consistent with distinct interaction natures. HLE17 electronic-structure calculations further demonstrate that adsorption induces substantial band-edge modulation: the nearly gapless Fe–GY substrate (0.007 eV) develops opened gaps upon VOC adsorption (0.192, 0.362, and 0.392 eV for HCHO, acetone, and benzene, respectively). Additional orbital analyses indicate that the benzene-induced gap opening arises from functional-sensitive adsorbate–substrate frontier-level alignment rather than strong charge-transfer-driven orbital hybridization. Together with PDOS, OPDOS/COOP, charge-density-difference, IGMH, magnetic-moment, and AIMD analyses, these results provide a more cautious mechanistic picture linking adsorption energetics, spin-dependent electronic perturbation, and sensing-relevant electronic response, highlighting Fe–GY as a viable candidate platform for VOC adsorption while emphasizing the need to consider O2 competition under realistic atmospheres.