1：Experimental Design and Method Selection:

The study employs a hydrothermal route for synthesizing Bi4Ti3O12 square plates and CQDs, followed by assembly of CQDs on Bi4Ti3O12 via another hydrothermal step. Characterization methods include XRD, SEM, TEM, UV-vis DRS, XPS, FTIR, PL, EIS, and photocurrent spectroscopy to analyze structure, morphology, optical properties, and electrochemical behavior. Photocatalytic activity is evaluated by degrading RhB under simulated sunlight and visible light.

2：Sample Selection and Data Sources:

Bi4Ti3O12 samples are prepared at 200°C with reaction times of 3, 6, 12, 24, and 36 h to study growth. CQDs are derived from glucose. Composite samples with varying CQDs content (5, 10, 15, 20 mL) are designated as 5CQDs@Bi4Ti3O12, etc.

3：List of Experimental Equipment and Materials:

Equipment includes D8 Advance x-ray diffractometer (Bruker AXS), JSM-6701F SEM (JEOL), JEM-1200EX TEM (JEOL), TU-1901 UV-vis spectrophotometer (Beijing Purkinje), PHI-5702 XPS spectrometer (Physical Electronics), Spectrum Two FTIR spectrophotometer (PerkinElmer), RF-6000 fluorescence spectrophotometer (Shimadzu), CST 350 electrochemical workstation (Wuhan Corrtest). Materials include Bi(NO3)3·5H2O, TiCl4, NaOH, glucose, RhB, ethanol, benzoquinone, ammonium oxalate, Na2SO4, acetylene black, PVDF, NMP, FTO glass.

4：Experimental Procedures and Operational Workflow:

Synthesis involves dissolving precursors, hydrothermal treatment at specified temperatures and times, centrifugation, washing, drying. Photocatalytic testing involves loading catalyst into RhB solution, stirring in dark, irradiating with xenon or halogen-tungsten lamp, sampling, centrifuging, measuring absorbance. Electrochemical measurements use a three-electrode cell with working electrode prepared from catalyst paste on FTO.

5：Data Analysis Methods:

XRD patterns indexed to PDF standards; UV-vis DRS used to determine bandgap via absorption edge; photocatalytic degradation analyzed using pseudo-first-order kinetics; EIS data interpreted via Nyquist plots; XPS spectra deconvoluted for chemical states.