1：Experimental Design and Method Selection:

A two-step hydrothermal method was used to in situ grow TiO2 nanosheets on Ti3C2 MXene and deposit MoS2 nanosheets on the (101) facets of TiO

2：Sample Selection and Data Sources:

Ti3AlC2 powder was etched to obtain Ti3C2 MXene; TiO2 nanosheets were synthesized using Ti(OBu)4 or from Ti3C2; MoS2 was deposited using Na2MoO4·2H2O and thiourea.

3：List of Experimental Equipment and Materials:

Hydrofluoric acid, hydrochloric acid, sodium tetrafluoroborate, sodium molybdate dihydrate, thiourea, Teflon-lined stainless-steel autoclaves, vacuum oven, X-ray diffractometer (XRD, D/Max 2500PC Rigaku), scanning electron microscope (FESEM, FEI Nova Nanosem 450), transmission electron microscope (HRTEM, JEOL JEM 2100F), X-ray photoelectron spectrometer (XPS, Thermo ESCALAB 250XI), UV–vis spectrophotometer (Hitachi UV-3101), BET surface area analyzer (Micromeritics ASAP2020), fluorescence spectrometer (FLS920), Xe arc lamp (CELHXF300), gas chromatograph (Techcomp GC-7920).

4：0). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Ti3C2 was prepared by etching Ti3AlC2 with HF; Ti3C2@TiO2 was synthesized hydrothermally with HCl and NaBF4; Ti3C2@TiO2@MoS2 was prepared by hydrothermal treatment with Na2MoO4·2H2O and thiourea; photocatalytic tests were conducted in a Pyrex glass vessel with a Xe lamp, and hydrogen was analyzed by gas chromatography.

5：Data Analysis Methods:

XRD for phase analysis, SEM/TEM for morphology, XPS for chemical states, UV–vis DRS for optical properties, BET for surface area, PL for charge separation, photocurrent and EIS for electrochemical properties.