1：Experimental Design and Method Selection:

The hybrid material was developed by mixing Eu[Pc(OC4H9)8]2 with aMWCNTs through non-covalent interactions. The gas-sensing devices were fabricated using a simple solvent-processing quasi-Langmuir–Sh?fer (QLS) method.

2：Sample Selection and Data Sources:

The sandwich-type double-decker complex Eu[Pc(OC4H9)8]2 was synthesized according to a previously reported method. Multiwalled carbon nanotubes (purity > 95%, ~50 μm in length, diameter 8–15 nm) were purchased from Aladdin.

3：List of Experimental Equipment and Materials:

UV-vis spectrum, X-ray diffraction, and scanning electron microscope were used to characterize the hybrid material. The gas-sensing devices were exposed to different concentrations of NO2 (0.3 to 0.9 ppm) and NH3 (0.5 to 25 ppm) in N2 atmosphere at room temperature.

4：3 to 9 ppm) and NH3 (5 to 25 ppm) in N2 atmosphere at room temperature. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The electrical responses of the hybrid film, pristine Eu[Pc(OC4H9)8]2, and aMWCNTs films were recorded at room temperature. The sensitivity was calculated for each concentration.

5：Data Analysis Methods:

The percent current change was calculated for each concentration to assess the sensitivity of the films towards NO2 and NH3.