fig4

Figure 4. (A) Temperature-dependent response to 10 ppm H₂S (30% RH), measured at 30, 50, 70, 90, and 110 °C; (B) Humidity-dependent H₂S response at 90 °C; (C) Bi₂Te₃ loading optimization for H₂S detection (90 °C, 30% RH); (D) Response comparison of Bi₂Te₃@ NiO_x sensor (error bars: SD, n = 5); (E) Response - recovery transient of 10% Bi₂Te₃@NiO_x to 10 ppm H₂S (first cycle); (F) Dynamic responses to varying H₂S concentrations; (G) Concentration-response relationship (inset: linear range 0.2-4 ppm; stars: experimental data; red curve: nonlinear fit); (H) Selectivity toward 10 ppm of various gases; (I) Long-term stability tests. RH: Relative humidity.