1：Experimental Design and Method Selection:

The study involved synthesizing Cu2O nanocubes via a solution method and then forming Cu7S4 layers on them through anion exchange to create a core-shell structure. The rationale was to leverage the localized surface plasmon resonance (LSPR) of Cu7S4 to enhance photocatalytic properties.

2：Sample Selection and Data Sources:

Samples included pure Cu2O, Cu7S4, and Cu2O/Cu7S4 nanocubes with varying degrees of sulfuration (e.g., S-x/Cu2O where x is the mole ratio of Na2S to Cu2O). Data were obtained from material characterizations and photocatalytic tests.

3：List of Experimental Equipment and Materials:

Equipment included XRD (Brooker D8 advanced), SEM (JSM-7800F), TEM (JEOL 2100-F), UV-VIS-NIR spectrophotometer (Lambda 750), XPS (Kratos AXIS Ultra DLD), gas chromatography (GC-2014), and electrochemical station (CHI 660D). Materials included CuCl2·2H2O, NaOH, L-ascorbic acid, Na2S·9H2O, Na2SO3, and others from suppliers like Sinopharm Chemical Reagent Co., Ltd.

4：Experimental Procedures and Operational Workflow:

Cu2O nanocubes were synthesized by mixing CuCl2, NaOH, and L-AA solutions, followed by centrifugation and freeze-drying. Cu2O/Cu7S4 NCs were formed by adding Na2S to Cu2O dispersion under stirring, then isolating and washing. Photocatalytic hydrogen evolution tests were conducted in a quartz cell with Na2SO3 as a sacrificial agent under Xe lamp irradiation, with hydrogen measured by GC. Photoelectrochemical measurements used a three-electrode setup with FTO working electrodes.

5：Data Analysis Methods:

Data were analyzed using techniques like Tauc plots for bandgap calculation, Mott-Schottky plots for carrier concentration, and statistical analysis of photocatalytic rates.