Nonmetal Plasmon-Induced\nCarrier Backflow and Prolonged\nLifetime for CO<sub>2</sub> Photoreduction

Constructing traditional heterojunctions involving noble\nmetal\ncocatalysts is a well-established strategy for boosting photocatalytic\nefficiency by separating electron/hole pairs and improving light absorption\nthrough localized surface plasmon resonance (LSPR) effects. However,\nthe high cost and limited availability of noble metals constrain their\napplication, while the impact of plasmon effects on charge carrier\ndynamics and lifetimes, crucial for regulating photocatalytic performance,\nhas been overlooked. Here, we propose integrating graphitic carbon\ndots (CDs) as proficient nonmetal cocatalysts into SnO<sub>2</sub> nanofibers to facilitate high-efficiency photoreactions. Under light\nirradiation, photoelectrons within the SnO<sub>2</sub> migrate to\nthe CDs driven by the bent bands and the internal electric field,\nalongside inherent free electrons, stimulating into high-energy excited\nelectrons due to LSPR effects. These energized electrons subsequently\nbackflow to the SnO<sub>2</sub> for stabilization, initiating a cyclic\nprocess that effectively prolongs carrier lifetimes within the SnO<sub>2</sub>/CDs nanohybrids, as confirmed by femtosecond transient absorption\nspectroscopy. Synergizing with enhanced optical absorption and CO<sub>2</sub> chemisorption facilitated by the CDs, the resulting SnO<sub>2</sub>/CDs nanofibers demonstrate improved CO<sub>2</sub> photoreduction\nperformance.