1：Experimental Design and Method Selection:

A facile thermal polymerization method was used to synthesize MACN with malonic acid and urea as precursors. The synthesis involved heating in a muffle furnace to 550°C for 4 hours with a heating rate of 2°C/min. Photocatalytic experiments were conducted using a photochemical reactor with a 500 W Xe lamp as the light source, equipped with a 420 nm cutoff filter for visible light experiments.

2：Sample Selection and Data Sources:

Samples included pristine CN and xMACN (x =

3：5, 1, 3, 10, representing weight ratios of malonic acid to urea). Bisphenol A (BPA) at 15 ppm concentration was used as the pollutant. List of Experimental Equipment and Materials:

Equipment included a muffle furnace, photochemical reactor (Xujiang Electromechanical plant), Xe lamp (500 W), high-performance liquid chromatography (HPLC, e2685, Waters), UV-Vis detector (2489, Waters), TEM, SEM, XRD, FT-IR, XPS, UV-Vis DRS, PL, EPR, BET surface area analyzer, and Mott-Schottky measurements. Materials included urea (Sinopharm Chemical Reagent Co., Ltd), malonic acid (TCI), t-butylalcohol (Chengdu Kelon Chemical Reagent Co., Ltd), KI (Shanghai Hushi Laboratorial Equipment Co., Ltd), TEMPOL (Shanghai Hansi Chemical Co., Ltd), DMPO (Sigma-Aldrich Co. LLC), and BPA (Shanghai Aladdin Biochemical Technology Co., Ltd).

4：Experimental Procedures and Operational Workflow:

For synthesis, urea and malonic acid were ground and heated. For photocatalytic tests,

5：02 g catalyst was dispersed in 50 mL BPA solution, stirred for 1 h in dark for adsorption equilibrium, then irradiated. Samples were collected at intervals, filtered, and analyzed by HPLC. Trapping experiments used scavengers for active species. Recycling tests involved centrifugation, washing, and drying of catalyst. Data Analysis Methods:

Data were analyzed using pseudo-first-order kinetic model for degradation rates, Kubelka-Munk method for bandgap calculation, and various characterization techniques for structural and optical properties.