1：Experimental Design and Method Selection:

A facile solvothermal method was used to synthesize CoO@MoS2 composites by coating MoS2 onto CoO octahedrons. The design aimed to enhance photocatalytic activity and stability.

2：Sample Selection and Data Sources:

CoO octahedrons were synthesized from Co(CH3COO)2·4H2O, and MoS2 was added in different weight percentages (1%, 3%, 5%) to form composites. Materials were purchased from Sinopharm Chemical Reagents Co., Ltd and Macklin Chemical Reagents Co., Ltd.

3：List of Experimental Equipment and Materials:

Equipment included X'Pert-ProMPD X-ray diffractometer, FEI-quanta 200 SEM, FEI-Tecnai F20 TEM/HRTEM/HAADF-SEM, KRATOS Axis ultra-DLD XPS, Lambda 750 UV-vis spectrophotometer, CHI 920C workstation for photocurrent and EIS, Micromeritics ASAP-2050 porosimeter for BET, PCX-50C photochemical reaction device, GC-7900 gas chromatograph. Materials included Co(CH3COO)2·4H2O, MoS2, ethanol, n-octanol.

4：Experimental Procedures and Operational Workflow:

CoO was synthesized by solvothermal reaction at 220°C for 4h. Composites were made by adding MoS2 during synthesis. Characterization involved XRD, SEM, TEM, XPS, UV-vis, photocurrent, EIS, BET. Photocatalytic tests were done in a multichannel reactor with LED light, and gases were detected by GC.

5：4h. Composites were made by adding MoS2 during synthesis. Characterization involved XRD, SEM, TEM, XPS, UV-vis, photocurrent, EIS, BET. Photocatalytic tests were done in a multichannel reactor with LED light, and gases were detected by GC. Data Analysis Methods:

5. Data Analysis Methods: Data were analyzed using standard techniques for XRD peak indexing, UV-vis for band gap calculation via Kubelka-Munk function, photocurrent and EIS for charge separation efficiency, and BET for surface area.