Constructing a step-scheme (S-scheme) heterojunction represents a promising route to overcome the drawbacks of single-component and traditional heterostructured photocatalysts by simultaneously broadening the optical response range and optimizing the redox ability of the photocatalytic system, the efficiency of which greatly lies in the separation behaviors of photogenerated charge carriers with strong redox capabilities. Herein, we demonstrate interfacial facet engineering as an effective strategy to manipulate the charge transfer and separation for substantially improving the photocatalytic activities of S-scheme heterojunctions. The facet engineering is performed with the growth of ZnIn 2 S 4 on ( 010) and (001) facet-dominated BiOBr nanosheets to fabricate ZIS/BOB-(010) and ZIS/BOB-(001) S-scheme heterojunctions, respectively. It is disclosed that a larger Fermi level difference between BiOBr-(001) and ZnIn 2 S 4 enables the formation of a stronger built-in electric field with more serious band bending in the space charge region around the interface. As a result, the directional migration and recombination of pointless photoexcited electrons in the conduction band (CB) of BiOBr and holes in the valence band (VB) of ZnIn 2 S 4 with weak redox ability are speeded up enormously, thereby contributing to more efficient spatial separation of powerful CB electrons of ZnIn 2 S 4 and VB holes of BiOBr for participating in overall redox reactions. Profiting from these merits, the ZIS/BOB-(001) displays a significant superiority in photocatalytic H 2 evolution over ZIS/BOB-(010) and mono-component counterparts. This work provides new deep insights into the rational construction of a S-scheme photocatalyst based on an interfacial facet design from the viewpoint of internal electric field regulation.
Exploring highly efficient heterostructured photocatalysts for converting CO2 to value-added chemicals has long been pursued, which is mainly limited by inefficient visible/near-infrared (NIR) photon capture, undesirable electron-hole recombination, and insufficient...
Coupling hollow semiconductor with metal–organic frameworks (MOFs) holds great promise for constructing high‐efficient CO2 photoreduction systems. However, energy band mismatch between them makes it difficult to exert their advantages to maximize the overall photocatalytic efficiency, since that the blockage of desirable interfacial charge transfer gives rise to the enrichment of photoelectrons and CO2 molecules on the different locations. Herein, an interfacial engineering is presented to overcome this impediment, based on the insertion of plasmonic metal into the heterointerfaces between them, forming a stacked semiconductor/metal@MOF photocatalyst. Experimental observations and theoretical simulations validate the critical roles of embedded Au in maneuvering the charge separation/transfer and surface reaction: (i) bridges the photoelectron transfer from hollow CdS (H‐CdS) to ZIF‐8; (ii) produces hot electrons and shifts them to ZIF‐8; (iii) induces the formation of ZIF‐8 defects in promoting the CO2 adsorption/activation and transformation to CO with low energy barriers. Consequently, the as‐prepared H‐CdS/Au@ZIF‐8 with optimal ZIF‐8 thickness exhibits distinctly boosted activity and superb selectivity in CO production as compared with H‐CdS@ZIF‐8 and other counterparts. This work provides protocols to take full advantages of components involved for enhanced solar‐to‐chemical energy conversion efficiency of hybrid artificial photosynthetic systems through rationally harnessing the charge transfer between them.
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