Constructing h-BN/Bi2WO6 Quantum Dot Hybrid with Fast Charge Separation and Enhanced Photoelectrochemical Performance by using h-BN for Hole Transfer

Bi2WO6 quantum dot (QD)-decorated hexagonal boron nitride (h-BN) nanosheets were prepared by using a one-step hydrothermal synthesis method. The Bi2WO6 QDs with a size of 4-8nm are anchored uniformly on the h-BN nanosheets with boron vacancies to form a h-BN/Bi2WO6 QD hybrid. The h-BN nanosheets not only function as a good support for Bi2WO6 QDs to block agglomeration, but also serve as a promoter for h(+) transfer to improve the charge separation in the hybrid material. The photoelectrochemical (PEC) performance of the photoanodes was evaluated by using linear sweep voltammetry, electrochemical impedance spectroscopy, Bode plots, and Mott-Schottky analyses. The results indicate that h-BN/Bi2WO6 QD hybrids show enhanced PEC performance, which is mainly embodied in a higher photocurrent density, better electron transport properties, longer electrons lifetime, and increased carrier density. Finally, a possible mechanism for the enhanced PEC performance is proposed and discussed.