Hole transfer and photothermal effect of carbon layer on TiO2 photoanode for efficient photoelectrochemical water splitting

In this study, CdS/C/TiO 2 photoanodes were prepared, and a dual-effect strategy combining hole transport and photothermal enhancement was adopted to improve the photoelectrochemical performance. • The hole storage and transport function of the carbon layer. • photothermal effect of the ultra-thin carbon layer. • A strategy with dual effects of hole transport and photothermal enhancement to improve PEC performance. Efficient utilization of light energy and charge transfer are both important factors for optimizing the photoelectrochemical (PEC) performance of the photoanode. Herein, a CdS/C/TiO 2 photoanode was synthesized. A carbon layer with hole storage and transport function was inserted between the CdS/TiO 2 heterojunction to enhance the overall performance. Benefiting from the CdS/TiO 2 heterojunction and carbon layer (hole transport layer), the CdS/C/TiO 2 photoanode achieved a photocurrent density of 1.55 mA·cm −2 (1.23 V RHE ) and half-cell applied bias photon-to-current efficiency (ABPE) of 0.40 % (0.83 V RHE ), representing 10.3 times and 20 times enhancements over pristine TiO 2 , respectively. In addition, the inherent photothermal effect of the carbon layer assisted by near-infrared light further enhances the transfer of charge at the interface between the photoelectrode and electrolyte, and strengthens the driving force for water oxidation. This work presents a strategy with dual effects of hole transport and photothermal enhancement to improve PEC performance, which can also be widely applied to other photoelectrodes.