1：Experimental Design and Method Selection:

The study involved synthesizing MnO2/AC composites and MnO2 NPs using a chemical reduction method with NaOH as a reducing agent. The rationale was to create well-dispersed nanoparticles on a support material to enhance photocatalytic activity. Methods included chemical reduction, sonication, refluxing, and photodegradation experiments under UV and visible light.

2：Sample Selection and Data Sources:

Activated carbon was prepared from peanut shells. Congo red dye was used as the pollutant. Samples were characterized using SEM, AFM, TEM, EDX, XRD, FTIR, Zetasizer, and UV-Vis spectrophotometry.

3：List of Experimental Equipment and Materials:

Equipment included a tube furnace, sonicator, centrifuge, UV-Vis spectrophotometer, SEM (JEOL JSM-5910), AFM (Agilent 5500), EDX spectrometer (Inea 200), Zetasizer (Malvern ZS-90), and materials such as peanut shells, phosphoric acid, sodium hydroxide, Congo red dye, hydrogen, oxygen, nitrogen gases, and MnCl4·2H2O.

4：2O. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Synthesis of AC from peanut shells involved drying, acid soaking, carbonization, activation, and thermal treatment. Synthesis of MnO2/AC and MnO2 NPs involved sonication, dropwise addition of NaOH, refluxing, filtering, and drying. Photodegradation experiments involved adding catalyst to dye solution, sonicating, irradiating under UV or visible light, centrifuging, and measuring degradation with UV-Vis spectrophotometry.

5：Data Analysis Methods:

Degradation percentage was calculated using absorbance measurements. Data from characterization techniques were analyzed to determine morphology, composition, size, and stability.