1：Experimental Design and Method Selection:

The study used a nanosecond pulse dielectric barrier discharge (NP-DBD) plasma system for in-situ reduction-loading of silver nanoparticles onto filter paper. The process involved a simple "suspending-discharging-washing" method without thermal treatment. Ethanol was used as a green reducing agent under argon plasma.

2：Sample Selection and Data Sources:

Commercial filter paper (No.20, α-cellulose 99.9%) was used as the substrate. Samples were prepared by immersing filter paper in AgNO3 solutions of varying concentrations (0 mM, 5 mM, 10 mM, 15 mM, 20 mM).

3：9%) was used as the substrate. Samples were prepared by immersing filter paper in AgNO3 solutions of varying concentrations (0 mM, 5 mM, 10 mM, 15 mM, 20 mM). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included a plate-to-plate DBD reactor with quartz glass dielectric and stainless steel electrodes, nanosecond pulsed power generator (PPM1000S-1KES), mass flow controllers, bubbling bottle for ethanol, FE-TEM (JEM2100F), FT-IR spectrometer (VERTEX 80V), XRD (Rigaku D/max), XPS (K-Alpha), Raman spectrometer (HORIBA LabRAM Revolution), and UV-Vis spectrometer (Lambda 750). Materials included silver nitrate, ethanol, filter paper, sodium borohydride, and methylene blue.

4：0). Materials included silver nitrate, ethanol, filter paper, sodium borohydride, and methylene blue. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Filter paper was cut, immersed in AgNO3 solution, placed on the dielectric surface of the DBD reactor, and treated with plasma for 5 minutes under argon and ethanol vapor. After discharge, the paper was washed with a water-ethanol mixture and dried. Catalytic activity was tested by filtering a mixture of MB and NaBH4 through the treated paper.

5：Data Analysis Methods:

Characterization involved TEM for morphology, FT-IR for functional groups, XRD for crystallinity, XPS for bonding states, Raman spectroscopy for structural analysis, and UV-Vis spectroscopy for catalytic reduction monitoring.