1：Experimental Design and Method Selection:

The dendritic nanostructured surface was fabricated by helium plasma irradiation to a monocrystal W plate. The surface was partially oxidized on exposure to air at room temperature.

2：Sample Selection and Data Sources:

Three samples were prepared through oxidation for 12, 97, and 200 days, and another sample was prepared by further heat-treatment at 773 K for 2 h in air.

3：List of Experimental Equipment and Materials:

A monocrystal W plate (The Nilaco Corporation, 0:1 (cid:2) 8 (cid:2) 8 mm3,

4：95% purity), a 300 W extra high pressure Xe lamp (USHIOSPAX R300-3J), a spectrometer JASCO V-670, a ESCA-3300 (SHIMADZU) spectrometer, a field emission scanning electron microscope (FE-SEM, HITACHI S-4300), an ultra-high voltage transmission electron microscope (TEM, JEOL JEM-1000K RS), and a spectrophotometer JASCO V-Experimental Procedures and Operational Workflow:

The photoinduced reactions of MB were conducted by placing the dendritic sample and MB aqueous solution into a quartz cell, subsequently exposing the sample to near infrared light. The MB concentration was estimated from the absorption peak intensity.

5：Data Analysis Methods:

The photoinduced reaction activity was evaluated from the decrease rate of the MB concentration. XPS measurements were carried out for the samples before and after the MB decomposition reactions.