Piezoelectric polarization-induced internal electric field manipulation of the photoelectrochemical performance in Nd, Co codoped BiFeO3†
Abstract
Developing piezo-phototronic photocatalysts to substitute conventional photocatalysts may be an extremely challenging strategy for the effective photoeletrochemical (PEC) splitting of water. The coupling of piezoelectric polarization and semiconductor characteristics provides a feasible means to control charge transfer, recombination, or separation through the application of external strain. Herein, we used piezoelectric polarization as a built-in electric field to promote the separation of BiFeO3 photocarriers. Furthermore, we fabricated a Nd, Co co-doped BiFeO3 photoelectrode to reduce the band gap and enhance the absorption of solar light. In this study, the as-fabricated Bi0.8Nd0.2Fe0.9Co0.1O3 displayed an excellent photocurrent density of 2.48 mA cm−2 at 1.23 V vs. RHE, which was 4.42 times that of BiFeO3. After the Bi0.8Nd0.2Fe0.9Co0.1O3 was excited by the piezoelectric effect, its photocurrent density was 3.66 mA cm−2 at 1.23 V vs. RHE, which was 1.48 times that before the ultrasound treatment. The modification of Bi0.8Nd0.2Fe0.9Co0.1O3 improved the charge separation and transfer efficiency and achieved a better visible response and piezoelectric polarization, providing another way for water splitting. Hence, the mechanism solved the above key challenges and provides a promising strategy for solar-driven photoelectrochemical water splitting.