1：Experimental Design and Method Selection:

A polyol synthetic route was designed to prepare ultra-thin Pd nano sheath over Ag nanowires forming metal-metal core-shell nanocomposites. The synthesis involved one-pot synthesis of Pd assembly onto growing Ag NWs with Pd salts reduced over varied time intervals (20, 30, and 40 minutes) during Ag NW growth.

2：Sample Selection and Data Sources:

Three different Ag@Pd nanocomposites (Ag@Pd 20, 30, and 40) were synthesized based on the time interval of Pd salt introduction. Pure Ag NWs and pure Pd nanostructures were also prepared under similar conditions for comparison.

3：List of Experimental Equipment and Materials:

Materials included PdCl2 (Degussa), AgNO3 (Analytical reagent), ethylene glycol (Sigma Aldrich), PVP (Daejung Reagent Chemicals-Korea), ethanol, acetone, p-nitrophenol (UNI-CHEM), NaBH4 (Merck), and distilled water. Equipment included TESCAN MIRA3 XMU SEM with EDX, Bruker D-8 discoverer XRD, SHIMADZU UV 1800 spectrophotometer, and SHIMADZU RF-6000 Spectro Fluorometer.

4：Experimental Procedures and Operational Workflow:

Synthesis involved preheating ethylene glycol at 160°C, adding AgNO3 and PVP solutions dropwise to form Ag NWs, then adding PdCl2 solution at specific time intervals (20, 30, or 40 min). Reactions were stirred for 1 hour, cooled, washed with ethanol, and centrifuged at 6000 rpm. Characterization included SEM/EDX for morphology, XRD for crystallinity, UV-Vis for SPR, PL for fluorescence, and catalytic testing for reduction of 4-nitrophenol to 4-aminophenol using NaBH

5：Data Analysis Methods:

SEM images and EDX plots were analyzed for morphology and elemental composition. XRD patterns were interpreted for crystallographic phases. UV-Vis spectra were used to determine SPR and monitor catalytic reduction kinetics. PL spectra were analyzed for fluorescence properties. Reaction kinetics were determined by plotting 1/A against time to ascertain second-order kinetics.