Regulating Surface Energetics via Hetero-Interfacial Charge Transfer for Selective Photocatalytic Glycerol Oxidation

While extensive efforts have focused on enhancing photocatalytic (PC) activity via promoting charge separation, the correlation of internal charge transfer on PC selectivity has not been established, primarily due to the challenges in directly exploring the origins of surface catalysis. Herein, we elucidate this dependence by incorporating carbon nanotubes (CNTs) as an electron mediator into a ZnIn₂S₄/BiVO₄ heterojunction for the glycerol oxidation reaction (GOR). Transient absorption spectroscopy measurements reveal that the incorporation of CNTs promotes the hetero-interfacial charge transfer. Photoexcited electrochemical impedance spectroscopy and Kelvin probe force microscopy demonstrate that the surface hole distribution is rearranged upon inter-particulate charge transfer regulation, with the hole accumulation on BiVO₄ shifting negatively to facilitate glycerol oxidation. Moreover, the intensified internal charge transfer creates a hole-rich surface that favors hydroxyl species adsorption, driving selective glyceraldehyde generation. Operando transient-state photovoltage spectroscopy confirms that the enhanced inter-particulate charge transfer facilitates glycerol activation. Consequently, the CNT modification achieves a 6.2-fold enhancement in glyceraldehyde yield with a selectivity of 78.6%. Our findings bridge the connection between surface energetics and internal charge dynamics, providing new insight into PC selectivity adjustment.