1：Experimental Design and Method Selection:

The study employed a modified Hummers' method for the synthesis of graphene oxide nanosheets, involving chemical oxidation of graphite with strong oxidizing agents. Characterization techniques included FTIR, UV-vis, XRD, Raman spectroscopy, TEM, and TGA to analyze structural, optical, and thermal properties.

2：Sample Selection and Data Sources:

Purified graphite powder was used as the precursor. Samples were prepared by dispersing GO in ethanol ultrasonically for TEM analysis.

3：List of Experimental Equipment and Materials:

Equipment included FTIR spectrometer (Nicolet 5700), UV-vis spectrophotometer (Shimadzu UV-1601 PC), XRD diffractometer (Bruker D8 Advance), TEM (FEI/Philips CM12), TGA analyzer (Mettler Toledo TGA/SDTA 851e), and Raman microprobe (Renishaw 1000). Materials included graphite powder, hydrogen peroxide, sodium nitrate, hydrochloric acid, potassium permanganate, and sulfuric acid.

4：0). Materials included graphite powder, hydrogen peroxide, sodium nitrate, hydrochloric acid, potassium permanganate, and sulfuric acid. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Graphite was oxidized in concentrated sulfuric acid with sodium nitrate and potassium permanganate under controlled temperature and stirring conditions. The mixture was treated with hydrogen peroxide and water, filtered, washed, and dried. Characterization involved sample preparation and analysis using the specified instruments.

5：Data Analysis Methods:

Data from spectroscopic and microscopic analyses were interpreted to identify functional groups, crystal structure, absorption peaks, morphology, and thermal stability.