• • Fe3O4-Nv-12h achieves a total syngas production rate of 43.55 mmol g−1 h−1 with a CO/H2 ratio of approximately 1:1, representing an 805.2-fold enhancement over pristine Fe3O4, which is critical for industrial Fischer-Tropsch synthesis feedstocks.
• • Nitrogen vacancy introduction modulates the electronic structure of Fe3O4, acting as electron traps to suppress photogenerated charge carrier recombination, as confirmed by EPR and XPS, directly addressing the bottleneck of low quantum efficiency in CO2 photoreduction.
• • In situ FTIR spectroscopy identifies *COOH and *CO as key intermediates for CO formation, providing mechanistic evidence for the reaction pathway and enabling rational catalyst design for selective syngas production.
• • The catalyst operates under visible light (λ ≥ 420 nm), utilizing a photosensitizer and TEOA sacrificial donor, achieving a performance that surpasses reported state-of-the-art photocatalytic CO2-to-syngas systems at a 1:1 ratio, demonstrating practical viability for solar-driven carbon neutralization.