In-depth insight into facet-dependent charge movement behaviors and photo-redox catalysis: A case of {001} and {010} facets BiOCl.

A central issue in understanding photo-redox catalysis is the facet-dependent charge movement behaviors that include bulk charge separation, surface charge transfer and interfacial charge migration. To get in-depth insight into these complicated processes steered by different exposing facets, herein BiOCl with exposed (001) and (010) facets engaged as the model are investigated. The BiOCl-(010) and BiOCl-(001) single-crystalline sheets are separately synthesized via hydrothermal and hydrolysis routes. In contrast to BiOCl-(010), BiOCl-(001) demonstrates highly promoted photo-redox performance for H2 generation and degradation of pollutants. The facet-dependent charge movement behaviors were surveyed by surface photovoltage spectroscopy (SPV), transient photocurrent, linear sweep voltammetry, continuous wavelength photocurrent, and electrochemical impedance spectrum (EIS). All the photoelectrochemical and photoelectric measurement results reflect that BiOCl-(001) exhibits superior charge separation and migration efficiencies in the whole charge movement process than the BiOCl-(010). Besides, a higher charge carrier density (3.1-fold enhancement) was also observed for BiOCl-(001) compared to BiOCl-(010). Our current work is expected to further our understanding on facet-dependent charge movement behaviors and offer new insight into design of high-performance photocatalytic/photoelectrochemical materials.