1：Experimental Design and Method Selection:

A facile one-pot hydrothermal method was used to synthesize ZnO nanowires (ZNWs) and ZnO nanowires/Au nanoparticles hybrid (Au-ZNWs) with various Au concentrations. The method involves hydrothermal reaction at 140°C for 12 hours, followed by annealing at 400°C for 4 hours. Characterization techniques include XRD, SEM, TEM, XPS, and FTIR. Gas sensing measurements were performed using a stationary-state gas distribution method with a WS-30A gas sensing test system.

2：Sample Selection and Data Sources:

Samples include pure ZNWs and Au-ZNWs with 1, 2, and 5 mol% Au concentrations. Chemicals used are zinc chloride (ZnCl2), sodium carbonate anhydrous (Na2CO3), and chloroauric acid (HAuCl4·4H2O), all of analytical grade.

3：List of Experimental Equipment and Materials:

Equipment includes Teflon-lined stainless steel autoclave, electronic oven, X-ray diffractometer (PANalytical X'Pert Pro), field emission scanning electron microscope (ZEISS Ultra Plus), transmission electron microscope (JEOL 2100), XPS spectrometer (EscaLab 250Xi), FTIR spectrophotometer (NICOLET 380), and WS-30A gas sensing test system (Winsen Electronics Technology Co., Ltd). Materials include ZnCl2, Na2CO3, HAuCl4·4H2O, deionized water, ethanol, alumina tube, Au electrodes, Pt wires, Ni-Cr alloy coil.

4：Experimental Procedures and Operational Workflow:

Synthesis involves dissolving ZnCl2 and Na2CO3 in deionized water, transferring to autoclave, heating at 140°C for 12h, filtering, washing, drying. For Au-ZNWs, HAuCl4 solution is added, pH adjusted to 7, mixed, and same hydrothermal process followed. Gas sensors are fabricated by coating sample slurry on sensing electrode, assembling with heater, drying, and annealing at 350°C for 12h. Sensing measurements involve testing resistance in air and gas, with response defined as Rg/Ra for oxidizing gases.

5：2h. Sensing measurements involve testing resistance in air and gas, with response defined as Rg/Ra for oxidizing gases. Data Analysis Methods:

5. Data Analysis Methods: Data analyzed using XRD for phase structure, SEM and TEM for morphology, XPS for chemical composition, FTIR for functional groups. Gas sensing data analyzed for response, response time, recovery time, and selectivity using software from WS-30A system.