Piezo-potential induced redox of polyaniline and CdS/PANI heterostructures for efficient photoelectrochemical water splitting.

Photoelectrode materials with high electron-hole separation efficiency and long-lasting stability are extremely important for photoelectrochemical (PEC) water separation. In this paper, the CdS/PANI composite structure was prepared by a simple hydrothermal method to improve the stability of CdS while maximizing its excellent PEC properties. This system (CdS/PANI) utilizes the redox effect of PANI internal functional groups to accomplish electron-hole migration, which suppresses the photocorrosion of CdS without using any surface sacrificial agent. Meanwhile, the carrier separation is further promoted by the heterojunction structure formed by CdS/PANI under the stimulation of ultrasonic waves. The coordination of the above two effects achieves improved photocatalytic activity and enhanced stability. The electrochemical test results under ultrasonic conditions showed that the PANI composite on CdS increased the photocurrent density (1.23 V vs. RHE) from 1.68 mA/cm−2 to 2.62 mA/cm−2 compared to pure CdS. In addition, the stability of PEC is further enhanced and the photocorrosion rate decreases from 43% to 12%. This strategy provides a promising example for the development of more efficient organic-inorganic piezoelectric photoanode materials. • Design of CdS/PANI materials for the photoelectrochemistry of splitting water. • Enhanced carrier separation and transfer by forming CdS/PANI heterojunctions. • Redox properties of PANI reduce the photocorrosion of CdS promoting photocatalysis. • Piezoelectric effect by CdS stimulates the redox process of PANI. • Synergistic piezoelectric effect and redox promote the photocatalysis of CdS/PANI. [ABSTRACT FROM AUTHOR]