2D/1D MoS 2 /TiO 2 Heterostructure Photocatalyst with a Switchable CO 2 Reduction Product.

Regulating the transfer pathway of charge carriers in heterostructure photocatalysts is of great importance for selective CO 2 photoreduction. Herein, the charge transfer pathway and in turn the redox potential succeeded to regulate in 2D MoS 2 /1D TiO 2 heterostructure by varying the light wavelength range. Several in situ measurements and experiments confirm that charge transfer follows either an S-scheme mechanism under simulated solar irradiation or a heterojunction approach under visible light illumination, elucidating the switchable property of the MoS 2 /TiO 2 heterostructure. Replacing the simulated sunlight irradiation with the visible light illumination switches the photocatalytic CO 2 reduction product from CO to CH 4. 13 CO 2 isotope labeling confirms that CO 2 is the source of carbon for CH 4 and CO products. The photoelectrochemical H 2 generation further supports the switching property of MoS 2 /TiO 2 . Unlike previous studies, density functional theory calculations are used to investigate the band structure of Van der Waals MoS 2 /TiO 2 S scheme after contact, allowing to propose accurate charge transfer pathways, in which the theoretical results are well matched with the experimental results. This work opens the opportunity to develop photocatalysts with switchable charge transport and tunable redox potential for selective artificial photosynthesis.