1：Experimental Design and Method Selection:

The study involved preparing Ta3N5 nanorod-arrays via vapor-phase hydrothermal and nitriding processes, followed by modification with CoPi and Co(OH)2 using photoelectric chemical and chemical deposition methods. Electrochemical tests were conducted to analyze protection performance.

2：Sample Selection and Data Sources:

Samples included Ta3N5 nanorod-arrays on tantalum foil substrates and 304 stainless steel electrodes, with data from SEM, XRD, XPS, UV-Vis spectroscopy, and electrochemical measurements in 3.5 wt% NaCl solution.

3：5 wt% NaCl solution. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included SEM (INSPECT F50), XRD (X'pert PRO), XPS (ESCALAB250), UV-Vis spectrophotometer (V-770), potentiostat (PGSTAT302N Autolab), and Xe lamp (PLS-SXE 300). Materials included tantalum foil, NaCl, CoPi, Co(OH)2, and resin-paraffin mixture.

4：0). Materials included tantalum foil, NaCl, CoPi, Co(OH)2, and resin-paraffin mixture. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Ta3N5 was synthesized, modified, characterized, and tested electrochemically for open circuit potential and photocurrent under dark and illuminated conditions using a three-electrode system with Pt counter and Ag/AgCl reference electrodes.

5：Data Analysis Methods:

Data were analyzed using standard techniques for morphology, crystal structure, composition, and electrochemical properties, with comparisons between modified and unmodified samples.