Optimizing charge carrier dynamics in photocatalysts for enhanced CO2 photoreduction: Fundamental principles, advanced strategies, and characterization techniques

The photocatalytic conversion of CO 2 into valuable chemicals represents a significant strategy for addressing global warming and climate change. The effectiveness and selectivity of this process depend critically on the efficient separation of electron-hole pairs within photocatalysts. This review summarizes recent advancements in optimizing photocatalyst performance through enhanced charge carrier dynamics. We first detail the fundamental principles of free carrier dynamics and exciton interactions and then evaluate strategies for improving charge carrier separation and utilization, such as cocatalyst loading, heterojunction formation, photoelectron injection, and donor-acceptor systems. The role of advanced characterization methods, including photoluminescence, Kelvin probe force microscopy, transient absorption spectroscopy, electron paramagnetic resonance, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy, in elucidating charge carrier dynamics, is also reviewed. The review concludes by identifying current challenges and proposing future research perspectives on enhancing charge carrier dynamics to improve CO 2 reduction efficiency.