1：Experimental Design and Method Selection:

A series of Fe-doped SrTiO3 (FexSr1-xTiO3) products (0 ≤ x ≤ 0.20) were synthesized via a hydrothermal process followed by calcination at 700°C. The methodology includes material preparation, characterization, and photocatalytic activity evaluation to study the effects of Fe doping on N2 photofixation.

2：20) were synthesized via a hydrothermal process followed by calcination at 700°C. The methodology includes material preparation, characterization, and photocatalytic activity evaluation to study the effects of Fe doping on N2 photofixation. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Samples were prepared with varying Fe doping levels (x = 0 to 0.20) using Sr(NO3)2, Fe(NO3)3·9H2O, and Ti(C4H9O)4 as precursors. Data sources include synthesized materials and standard gases (e.g., N2, 15N2).

3：20) using Sr(NO3)2, Fe(NO3)3·9H2O, and Ti(C4H9O)4 as precursors. Data sources include synthesized materials and standard gases (e.g., N2, 15N2). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes Bruker D8 advance X-ray diffractometer (XRD), Zeiss-Sigma field emission scanning electron microscope (FESEM), JEM-2100 transmission electron microscope (HRTEM), Shimadzu UV-2550 spectrophotometer, VG Multilab 2000 XPS spectrometer, Bruker S4 Pioneer XRF spectrometer, Bruker X-band A-200 EPR spectrometer, Wissel MS-500 M?ssbauer spectrometer, Hitachi F-6800 fluorescence spectrophotometer, Micrometrics ASAP 2460 system, Nicolet Is50 spectrometer, Micromeritics Autochem 2, CHI model 618C electrochemical analyzer, 300 W Xe-lamp, and Shimadzu GC-2010 Plus gas chromatograph. Materials include ethylene glycol, NaOH, deionized water, Nessler's reagent, and 15N2 gas.

4：Experimental Procedures and Operational Workflow:

Synthesis involved dissolving precursors in ethylene glycol, adding NaOH, hydrothermal treatment at 200°C for 24 h, washing, drying, and calcination at 700°C for 4 h. Characterization included XRD, FESEM, TEM, XPS, XRF, PAS, EPR, M?ssbauer, PL, BET, in situ FTIR, N2-TPD, DRS, and photoelectrochemical measurements. Photocatalytic tests involved dispersing catalyst in water, bubbling N2, irradiating with Xe-lamp, and analyzing NH3 and O2 production.

5：Data Analysis Methods:

Data analysis used techniques such as XRD pattern matching with JCPDS standards, XPS peak deconvolution, BET surface area calculation, Mott-Schottky plots for flat-band potential determination, and spectrophotometric methods for NH3 quantification.