1：Experimental Design and Method Selection:

The study used a solvothermal reaction followed by annealing to synthesize pure and Mn-doped ZnO hollow structures. Theoretical models include Bragg's law for XRD analysis and semiconductor gas sensing mechanisms involving oxygen adsorption and redox reactions.

2：Sample Selection and Data Sources:

Samples included pure ZnO and Mn-doped ZnO with different Mn concentrations (e.g., 1% and 3% Mn). Data were sourced from laboratory experiments using synthesized materials.

3：List of Experimental Equipment and Materials:

Equipment included X-ray diffraction (XRD, D8 ADVANCE DAVINCI), scanning electron microscopy (SEM, Hitachi S4800), transmission electron microscopy (TEM, JEOL2100), high-resolution TEM (HRTEM, Tecnai F20), BET surface area analyzer (ASAP2020M), BJH pore size analyzer (ASAP2020M), and X-ray photoelectron spectroscopy (XPS, Axis Ultra DLD). Materials included Zn(NO3)2·6H2O, isophthalic acid (H2IPA), N,N-Dimethylformamide, acetone, Mn(NO3)3·4H2O, and Teflon-lined stainless steel autoclave.

4：Experimental Procedures and Operational Workflow:

For synthesis, reagents were dissolved in a mixed solvent, transferred to an autoclave, treated at 160°C for 4 hours, cooled, centrifuged, dried at 60°C for 12 hours, and annealed at 500°C for 1.5 hours. Gas sensors were fabricated as per previous work, with temperature calibrated using infrared ray and gas flow optimized. Sensing tests involved exposing sensors to various gases at different temperatures and concentrations, measuring resistance changes.

5：5 hours. Gas sensors were fabricated as per previous work, with temperature calibrated using infrared ray and gas flow optimized. Sensing tests involved exposing sensors to various gases at different temperatures and concentrations, measuring resistance changes. Data Analysis Methods:

5. Data Analysis Methods: Data were analyzed using XRD for crystal structure, SEM/TEM for morphology, BET/BJH for surface area and pore size, XPS for chemical composition, and resistance measurements (Ra/Rg for n-type sensors) for gas response. Statistical analysis included error bars for reproducibility.