Interfacial Charge Transfer in MoS2/TiO2 Heterostructured Photocatalysts: The Impact of Crystal Facets and Defects

Abstract

One of the most challenging issues in photocatalytic hydrogen evolution is to efficiently separate photocharge carriers. Although MoS2 loading could effectively improve the photoactivity of TiO2, a fundamental understanding of the charge transfer process between TiO2 and MoS2 is still lacking. Herein, TiO2 photocatalysts with different exposed facets were used to construct MoS2/TiO2 heterostructures. XPS, ESR, together with PL measurements evidenced the Type II electron transfer from MoS2 to {001}-TiO2. Differently, electron-rich characteristic of {101}-faceted TiO2 were beneficial for the direct Z-scheme recombination of electrons in TiO2 with holes in MoS2. This synergetic effect between facet engineering and oxygen vacancies resulted in more than one order of magnitude enhanced hydrogen evolution rate. This finding revealed the elevating mechanism of constructing high-performance MoS2/TiO2 heterojunction based on facet and defect engineering.

Facile synthesis and defect optimization of 2D-layered MoS2 on TiO2 heterostructure for industrial effluent, wastewater treatments

“…The presence of diffraction of anatase TiO 2 suggests that 2D-MoS 2 nanosheets loading does not change the crystal phase of TiO 2 . On the other hand, no apparent peaks for MoS 2 could be detected, due to its relatively lower amount along with its high dispersity and week intensity that is in well agreed with previous reports 37 , 38 . Further, no other impurity peaks are observed in the XRD patterns evidencing the single-phase formation of the samples.…”

“…The shift of Ti2p peaks to higher binding energies indicates the functioning of Ti atom as an electron donor. The surface dependent interfacial electronic structure implies the exchange charge transfer behaviour between MoS 2 and TiO 2 heterostructures 37 .…”

“…Moreover, the charge carriers in semiconductor photocatalyst strongly depends on the exposed facets and structural defects. Consider the example of (001) and (101) facets/phase of TiO 2 , two most common facets of anatase phase, usually exhibit different adsorption characteristics and redox abilities during the photocatalytic reaction 37 , 66 , 67 .…”

Porous V2O5/TiO2 Nanoheterostructure Films with Enhanced Visible-Light Photocatalytic Performance Prepared by the Sparking Method

“…In particular, the large surface areas of 1-D structures and porous morphology are preferred in the design [ 5 , 6 ]. Moreover, composite films with a narrow band gap semiconductor are preferred, which can lead to superior performance of the pure TiO 2 films [ 7 , 8 , 9 ]. Both TiO2 and V 2 O 5 are two important materials due to their excellent electronic, chemical, and optical properties [ 10 , 11 ].…”

The Combination of MoS2/WO3 and Its Adsorption Properties of Methylene Blue at Low Temperatures

“…Its layered structure is sandwiched together by Mo-S-Mo units with a weak van der Waals force [9], and the direct band gap is 1.82 eV [10]. This unique structure gives MoS 2 stable chemical properties, an adjustable band gap, a large specific surface area, and an abundant layered edge to provide a large number of unsaturated active sites [11]. Therefore, MoS 2 is expected to become a high-performance adsorbent.…”