1：Experimental Design and Method Selection:

The study involved synthesizing TiO2 nanotubes via hydrothermal method and CoFe2O4 nanoparticles via co-precipitation, followed by creating nanocomposites using wet impregnation. Photocatalytic reduction of 4-nitrophenol was conducted under UV light with NaBH4 as a reducing agent.

2：Sample Selection and Data Sources:

Samples included TiO2 P25 precursor, synthesized TNTs, CF nanoparticles, and TCF nanocomposites. Data were sourced from material characterizations and photocatalytic experiments.

3：List of Experimental Equipment and Materials:

Equipment included autoclave, magnetic stirrer, sonicator, XRPD diffractometer (Siemens D-500), SEM (Jeol JSM 7401F), Raman microscope (Renishaw Via Reflex), FTIR spectrometer (Thermo Scientific Nicolet 6700), UV-Vis spectrophotometer (Hitachi 3010), BET surface area analyzer, SQUID magnetometer (Quantum Design PPMS), and UV photoreactor with Sylvania TLD 15W/08 lamps. Materials included TiO2 P25 (Evonik), NaOH, HCl, Co(NO3)2·6H2O, Fe(NO3)3·9H2O, methanol, 4-nitrophenol, NaBH4, and various scavengers.

4：Experimental Procedures and Operational Workflow:

Synthesis of TNTs involved hydrothermal treatment at 150°C for 24h, washing, and calcination. CF synthesis involved co-precipitation at pH 11, stirring at 90°C, and calcination. TCF synthesis involved impregnation in methanol with sonication and drying. Photocatalytic experiments involved adding catalyst to 4-NP and NaBH4 solution, stirring in dark for

5：5h, UV irradiation, and monitoring with UV-Vis spectroscopy. Recyclability tests involved multiple cycles with magnetic separation or centrifugation. Data Analysis Methods:

Data were analyzed using Rietveld refinement (FULLPROF software), BET and BJH methods for surface area, and UV-Vis spectroscopy for concentration calculations based on calibration curves.