Boron Doping‐Induced Ultrahigh Ce 3+ Ratio in Amorphous CeO 2 /GO Catalyst for Low‐Concentration CO 2 Photoreduction

Abstract Direct utilization of diluted CO 2 enables sustainable CO 2 conversion into valuable products, with reduced CeO 2 emerging as an attractive candidate due to its exceptional redox flexibility. The catalytic efficacy of CeO 2 is intimately tied to the electronic structure of 4 f , yet the persistent challenge lies in maintaining a high and stable concentration of Ce 3+ . In this study, we propose a symmetry‐breaking‐induced amorphization strategy to achieve an exceptionally high Ce 3+ ratio by B doping, which facilitates the reduction of Ce 4+ to Ce 3+ in amorphous CeO 2 . First‐principles calculations and infrared spectroscopy reveal that B doping with three excess electrons induces the formation of planar triangular B–O₃ units by disrupting the original high‐symmetryF m 3 ¯ m $Fm\bar 3m$ structure of CeO 2 , facilitating the spontaneous transition to the amorphous phase. Electronic structure analysis confirms that even a modest 7.5% B doping can significantly elevate the Ce 3+ ratio to 85.7%. The resulting amorphous B‐doped CeO 2 /GO shows a remarkable CO 2 ‐to‐CO conversion rate of 249.33 µmol g −1  h −1 (under 15% CO 2 ) and 103.4 µmol g −1  h −1 (under 1% CO 2 ), with 100% selectivity in both cases. This performance highlights how amorphization stabilizes defect states, making amorphous CeO 2 /GO with high Ce 3+ an effective material for CO 2 photoreduction and addressing key challenges in CO 2 capture and utilization.