fig2

From: Recent advances in room-temperature hydrogen sulfide gas sensors: materials design, interface engineering, and sensing mechanisms

Figure 2. Performance and mechanisms of 2D-material-based H₂S sensors. (A) MXene/PbS responses to 10 ppm H₂S under NIR irradiation (0.525 W cm^-2, A₁), varied 808 nm power (A₂), and NIR, matched-temperature heating, and UV conditions (A₃), with in situ DRIFTS under dark and NIR conditions (A₄-A₅). Reproduced with permission from Ref.^[126]. Copyright 2025, Wiley-VCH; (B) PCA plots of the M-COF-DC-8 (M = Fe, Co, Ni, Cu) array responses, evaluating discrimination of the carrier gas, NO, CO, H₂S, and NH₃ and their different concentrations (B₁); PCA plot evaluating discrimination of NO, CO, H₂S, and NH₃ (80 ppm) by the M-COF-DC-8 (M = Co, Ni, Cu) array under humidity, with compressed response vectors under dry (training) and humid (projected onto dry-trained PCs) conditions (B₂). Reproduced from Ref.^[39], under CC BY 4.0 license. For Figure 2A₁-A₃, response (%) = (R_air - R_gas)/R_air × 100%, where R_air and R_gas denote the resistances in air and H₂S, respectively. DRIFTS: Diffuse reflectance infrared Fourier transform spectroscopy; NIR: near-infrared; PCA: principal component analysis; UV: ultraviolet; COF: covalent organic framework; PC: principal component.