1：Experimental Design and Method Selection:

A pyrolysis method was used to prepare biomass-derived CQDs from biomass residue under a N2 atmosphere at temperatures ranging from 300 (cid:1)C to 500 (cid:1)C.

2：Sample Selection and Data Sources:

Biomass residue was obtained from the residues produced in the process of biodiesel production using crop stalks.

3：List of Experimental Equipment and Materials:

Quartz boat, tube furnace, ethanol, styrene, high-speed centrifuge, rotary evaporator, SEM (JSM-7500F), HR-TEM (FEI Tecnai G2 F20), optical microscopy (Olympus), FTIR (Nicolet iN10), XPS (Thermo Escalab 250), Raman spectroscopy (Thermo Scientific DXRxi), ultraviolet spectrometer (Hitachi U-4100 UV-Vis-NIR ultraviolet spectrometer), Fluoromax-4 fluorescence spectrometer, Texas-500 spinning drop tensiometer.

4：Experimental Procedures and Operational Workflow:

Biomass residue was pyrolyzed, dissolved into ethanol, centrifuged to obtain a supernatant, and then rotary evaporated and dried to obtain CQDs. The CQDs were characterized and used to prepare styrene-in-water Pickering emulsions, which were tested for stability.

5：Data Analysis Methods:

The morphology and particle size of CQDs were investigated using SEM, HR-TEM, and optical microscopy. The chemical structures of the CQDs were characterized using FTIR, XPS, and Raman spectroscopy. The ultraviolet and fluorescence spectra were measured, and the interfacial tension between water and oil was determined.