1：Experimental Design and Method Selection:

The study employed a high-temperature solid-state reaction method with dehydrogenation-driven synthesis using LuH3 as the lutetium source. A two-step heating process was used to optimize morphology and performance.

2：Sample Selection and Data Sources:

Raw materials included LuH3 (99.99%), Si3N4 (99.99%), SiC (99.99%), and CeN (99.99%) powders. Samples were prepared with varying Ce3+ concentrations and SiC content.

3：99%), Si3N4 (99%), SiC (99%), and CeN (99%) powders. Samples were prepared with varying Ce3+ concentrations and SiC content. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included a Netzsch STA 449F1-0292-M TG-DSC, Rigaku X-ray diffractometer, Bruker D8 Focus diffractometer, FEI Tecnai G2 F30 TEM, Hitachi SUI 510 SEM, Shimadzu UV-3600 Plus spectrophotometer, Horiba Fluoromax-4 spectrofluorometer, and Otsuka QE-2100 quantum yield measurement system. Materials were handled in a nitrogen-filled glovebox.

4：Experimental Procedures and Operational Workflow:

Mixtures were ground, sintered at 1973.15 K under N2/H2 atmosphere, and cooled. TG-DSC and XRD analyses were performed at various temperatures. Photoluminescence spectra, thermal quenching, and quantum efficiency were measured.

5：15 K under N2/H2 atmosphere, and cooled. TG-DSC and XRD analyses were performed at various temperatures. Photoluminescence spectra, thermal quenching, and quantum efficiency were measured. Data Analysis Methods:

5. Data Analysis Methods: Data were analyzed using Rietveld refinement with FullProf software, Arrhenius equation for thermal quenching, and CIE chromaticity coordinates for LED performance.