Inspired by natural photosynthesis, the design of new Z-scheme photocatalytic systems is very promising for boosting the photocatalytic performance of H2 production and CO2 reduction; however, until now, the direct synthesis of efficient Z-scheme photocatalysts remains a grand challenge. Herein, it is demonstrated that an interesting Z-scheme photocatalyst can be constructed by coupling In2 O3 and ZnIn2 Se4 semiconductors based on theoretical calculations. Experimentally, a class of ultrathin In2 O3 -ZnIn2 Se4 (denoted as In2 O3 -ZISe) spontaneous Z-scheme nanosheet photocatalysts for greatly enhancing photocatalytic H2 production is made. Furthermore, Mo atoms are incorporated in the Z-scheme In2 O3 -ZISe nanosheet photocatalyst by forming the MoSe bond, confirmed by X-ray photoelectron spectroscopy, in which the formed MoSe2 works as cocatalyst of the Z-scheme photocatalyst. As a consequence, such a unique structure of In2 O3 -ZISe-Mo makes it exhibit 21.7 and 232.6 times higher photocatalytic H2 evolution activity than those of In2 O3 -ZnIn2 Se4 and In2 O3 nanosheets, respectively. Moreover, In2 O3 -ZISe-Mo is also very stable for photocatalytic H2 production by showing almost no activity decay for 16 h test. Ultraviolet-visible diffuse reflectance spectra, photoluminescence spectroscopy, transient photocurrent spectra, and electrochemical impedance spectroscopy reveal that the enhanced photocatalytic performance of In2 O3 -ZISe-Mo is mainly attributed to its widened photoresponse range and effective carrier separation because of its special structure.
Keywords: Z-scheme; ZnIn2Se4; nanosheets; photocatalysis.
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