Modulation of the Charge Carriers Transfer Pathway for Enhanced Piezocatalytic H2 Production and Dye Degradation

In recent years, piezo-catalytic hydrogen production has been widely investigated for potential applications. Despite various strategies having been utilized to enhance the performance of piezocatalysts, there is a scant report on improving catalytic activity through the modulation of carrier migration pathways. Herein, we have successfully synthesized BiOCl with exposed {001} and {010} facets through facet engineering. The built-in electric field within the BiOCl crystals is oriented perpendicular to the {001} facets and parallel to the {010} facets, leading to differing charge carrier transfer pathways in the two samples. Specifically, in the BiOCl-010 sample, due to the electric field parallel to the nanosheet plane, charge carriers migrate along the x-axis. In contrast, in the BiOCl-001 sample, the electric field is perpendicular to the nanosheet plane, causing charge carriers to transfer along the z-axis, resulting in a shorter charge carrier migration distance. Consequently, BiOCl-001 demonstrates superior piezo-catalytic performance compared to BiOCl-010 toward H2 production and dye degradation. Both samples exhibit identical morphologies and similar energy band structures. Therefore, the enhanced performance is attributed to its shorter charge transport distance as well as the relatively higher piezoelectric coefficient associated with the {001} facets of BiOCl, which facilitates effective carrier separation.