Photoelectron transfer between heterojuctions is an important process for photocatalysis, and identification of the electron transfer process provides valuable information for catalyst design. Herein, Ti3C2, one of the widely used two‐dimensional materials, is used to produce a heterojunction of TiO2 and Ti3C2 by an in situ growth method and the photogenerated electrons transfer between the two components for photocatalytic water splitting to hydrogen is investigated. Theoretical simulation and experimental tests proclaim that electrons transfer from Ti3C2 to TiO2 forms an internal electric field, which implies that there exists the driving force of electronic movement from TiO2 to Ti3C2. In situ irradiation X‐ray photoelectron spectroscopy shows the binding energies of TiC (in Ti3C2) and TiO (in TiO2) move toward negative and positive positions, respectively, verifying the photogenerated electrons produced from TiO2 and transferring to Ti3C2 driven by the internal electric field. In addition, the amount of TiO2 nanoparticles also affects the hydrogen evolution rate. Several parallel experiments are designed to uncover the fact that less or excess amount of TiO2 nanoparticles leads to a tinier shift of binding energy, which hints the quantity of heterojunction is a considerable factor in photocatalytic performance. This work develops a new method to directly monitor the photoelectron transfer process between heterojuctions.

A sonochemical method has been developed to fabricate hierarchical TiO2/CdS hollow sphere heterostructures with excellent photocatalytic activity.

N-doped TiO2 with a three-dimensionally ordered macroporous structure was fabricated by a one-step colloidal crystal-template method, which showed excellent photocatalytic activity under visible-light irradiation.

Minimizing the charge transfer barrier to realize fast spatial separation of photoexcited electron−hole pairs is of crucial importance for strongly enhancing the photocatalytic H 2 generation activity of photocatalysts. Herein, we propose an electron transfer strategy by reasonable design and fabrication of high-density NiSx quantum dots (QDs) as a highly efficient cocatalyst on the surface of Cd 0.8 Zn 0.2 S/rGO nanosheet composites. Under visible-light irradiation, the formation of a two-dimensional (2D) Cd 0.8 Zn 0.2 S/rGO nanohybrid system with 2 wt % NiSx loading gave a prominent apparent quantum efficiency (QE) of 20.88% (435 nm) and H 2 evolution rate of 7.84 mmol g −1 h −1 , which is 1.4 times higher than that of Pt/ Cd 0.8 Zn 0.2 S/rGO. It is believe that the introduced rGO nanosheets and NiSx QDs obviously improved the interfacial conductivity and altered the spatial distribution of electrons in this nanoarchitecture. Thus, the synergistic effects of interfacial junctions result in a regulated electron transportation pathway along the basal planes and ultrafast transfer and spatial separation of photoexcited carriers, which are responsible for the enhanced photocatalytic performance. This work gives a facile and effective strategy to understand and realize rationally designed advanced photocatalysts for high-efficiency, stable, and cost-efficient solar hydrogen evolution applications.

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