1：Experimental Design and Method Selection:

The study utilized a photo-thermochemical cycle (PTC) for CO2 reduction. Sol-gel synthesized TiO2 (ST) and Mn-doped TiO2 (MT) films were produced and compared with commercial P25 TiO2 (PT). A xenon lamp was used as a simulated solar light source. Density functional theory (DFT) calculations were performed to support experimental findings.

2：Sample Selection and Data Sources:

Samples included PT, ST, and MT with Mn doping ratios of 0.5, 1.0, and 1.5 wt%. They were synthesized via sol-gel method and characterized using various techniques.

3：5, 0, and 5 wt%. They were synthesized via sol-gel method and characterized using various techniques. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included a xenon lamp for simulated sunlight, field-emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDXS), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Materials included TiO2 precursors and manganese dopants.

4：Experimental Procedures and Operational Workflow:

PTC experiments involved illuminating samples for 1 hour in He atmosphere and maintaining at 773 K for 1 hour in CO2 for multiple cycles. Characterization methods were applied to analyze physical and chemical properties before and after cycles.

5：Data Analysis Methods:

Data were analyzed using techniques such as Tauc method for band gap calculation, Bragg's law for XRD analysis, and DFT for theoretical modeling of defect formation and electronic properties.