1：Experimental Design and Method Selection:

The study used an incipient wetness impregnation method to load bismuth and lanthanide precursors into mesoporous silica nanoparticles (MSNs), followed by calcination at various temperatures to form core–shell structures. Techniques included XRPD, SR-XRPD, HR-TEM, SAXS, N2 adsorption-desorption, TG-DSC, FE-SEM, EDS, DRUV-Vis, and photoluminescence measurements.

2：Sample Selection and Data Sources:

MSNs were synthesized with specific molar ratios of reagents. Samples were prepared with different pore occupancy levels (12.5%, 25%, 50%, 100%) and annealed at temperatures from 550°C to 750°C. Data were collected from synthesized nanoparticles and characterized using various instruments.

3：5%, 25%, 50%, 100%) and annealed at temperatures from 550°C to 750°C. Data were collected from synthesized nanoparticles and characterized using various instruments. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included Philips diffractometer, synchrotron radiation setup, Kratky camera, Micromeritics ASAP 2010 system, thermogravimetric analyzer, Carl Zeiss Sigma VP FE-SEM, JEOL3010 TEM, JASCO V-570 spectrophotometer, CNI MDL-III-980 diode laser, QE65 Pro Ocean Optics spectrometer. Materials included TEOS, CTAB, ethanol, ammonium hydroxide, Bi(NO3)3·5H2O, Yb(NO3)3·5H2O, Er(NO3)3·5H2O, HNO

4：Experimental Procedures and Operational Workflow:

MSNs were synthesized, impregnated with precursor solutions, dried using a rotary evaporator, and calcined. Characterization involved step-by-step measurements: XRPD with Cu Kα radiation, in situ SR-XRPD with temperature control, SAXS, N2 physisorption, TG-DSC, microscopy, and spectroscopy under specific conditions (e.g., 980 nm excitation for PL).

5：Data Analysis Methods:

Data were analyzed using Scherrer equation for crystallite size, Rietveld refinement for phase quantification, BET and BJH models for surface area and pore size, SAXS fitting for size distributions, and Kubelka-Munk function for bandgap estimation.