1：Experimental Design and Method Selection:

The study employed a two-step hydrothermal and one-step carbonization method to synthesize MoC/MnO composite materials. The electrocatalytic properties were studied using electrochemical impedance spectroscopy (EIS), Tafel polarization, and cyclic voltammetry (CV).

2：Sample Selection and Data Sources:

The samples were characterized by XRD, XPS, SEM, and TEM to analyze their crystal structures, elemental composition, surface electronic states, microstructures, and surface morphologies.

3：List of Experimental Equipment and Materials:

Equipment included X-ray diffractometer (Rigaku, D/max-2500), X-ray photoelectron spectroscopy (XPS, ESCALAB 250Xi), scanning electron microscopy (SEM; Hitachi S-4800), transmission electron microscopy (TEM; JEOL JEM-2100), and an electrochemical workstation (ZAHNER ZENNIUM CIMPS-1).

4：1). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The synthesis involved hydrothermal treatment of precursors followed by carbonization. The CE films were prepared by a doctor blade method on FTO glass substrates.

5：Data Analysis Methods:

The data were analyzed using Z-view software for EIS results, and the photovoltaic parameters were measured using a solar light simulator and a solar cell spectral response measurement system.