Rational fabricating advanced photocatalysts to recycle CO2 into solar fuel is one of the most promising approaches to simultaneously address energy shortages and global warming. TiO2 has been widely used in photocatalytic CO2 reduction due to its abundant reserves, non-toxicity and harmlessness etc. However, it remains significantly challenging for practical applications due to the fast electron-hole recombination. Herein, we design a direct TiO2 based Z-Scheme heterojunction by self-assembly of C-doped TiO2 nanoparticles on 3D hierarchical petal of flower-like β-Bi2O3 (C-TiO2/β-Bi2O3). In situ electron paramagnetic resonance tests, in situ X-ray photoelectron spectroscopy and theoretical calculations reveal that electrons are transferred from β-Bi2O3 to C-TiO2 due to the formation of Z-Scheme heterojunction, which greatly accelerates the separation of photogenerated carriers to promote efficient CO2 photoreduction. Ultimately, the optimal heterojunction shows significantly enhanced photocatalytic activity for CO2 reduction to CO (31.07 μmol g–1 h−1) compared to the pure TiO2 (3.28 μmol g–1 h−1) without using any photosensitizers and sacrificial agents. This work provides a unique insight to design direct Z-Scheme heterojunctions and delivers a promising photocatalyst for overcoming global warming and energy-supply issues.
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