Au/TiO2/MoS2 plasmonic composite photocatalysts were synthesized via deposition-precipitation with urea. The photocatalytic activities of the prepared samples were evaluated by performing hydrogen production experiments under Xe lamp irradiation with a 10% (φ, volume fraction) glycerol aqueous solution as the sacrificial agent. The results showed that the optimal content of MoS2 in the Au/TiO2/MoS2 composite is 0.1% (w, mass fraction) and the corresponding H2 production rate was 708.85 μmol·h-1, which was almost 11 times higher than that of TM6.0 with the strongest photocatalytic activity in the all binary TiO2/MoS2 composites. The enhanced photocatalytic activity of the ternary Au/TiO2/MoS2 composites is mainly due to the surface plasmon resonance of the supported Au nanoparticles absorbed on the TiO2/MoS2 layered composite, which show an intense absorption maximum centered around 550–560 nm and induce the photoexcitation of electrons. Meanwhile, the electrons excited by surface plasmon resonance of Au could be injected into the conduction band of TiO2, and they were then transferred to the edges of MoS2 for catalyzing the production of H2.
Fund: the National Natural Science Foundation of China(21403079);the National Natural Science Foundation of China(51672099);Fundamental Research Funds for the Central Universities, Chin(2662015PY039);Fundamental Research Funds for the Central Universities, Chin(2662015PY210)
Fig 1 XRD patterns of the pure TiO2 and TiO2/MoS2 composites with different content of MoS2. The mass percentages of MoS2 to TiO2 were varied from 0 to 10% (0, 0.5%, 1.0%, 2.0%, 6.0%, 10% (w)) and the resulting samples were labeled as TiO2, TM0.5, TM1.0, TM2.0, TM6.0, TM10.
Fig 2 XRD patterns of the Au/TiO2/MoS2 composites with different content of MoS2. The content of Au was fixed at 2% (w) by varying the loading of MoS2 from 0 to 2.0% (0, 0.1%, 0.5%, 1.0%, 2.0% (w)) and the resulting Au/TiO2/MoS2 composites were labeled as AT, ATM0.1, ATM0.5, ATM1.0, ATM2.0.
Fig 3 TEM and HRTEM images of the as-prepared TM6.0 and ATM0.1 samples. TEM: (a) TM6.0, (b) ATM0.1; HRTEM: (c) TM6.0, (d) ATM0.1.
Fig 4 SEM (a, b) and EDX (c–h) images of ATM1.0 sample.
Fig 5 Survey XPS spectrum of ATM1.0 sample. The inset shows a high resolution spectrum of Au 4f.
Fig 6 High resolution XPS spectra of Mo 3d-S 2s of ATM1.0 sample.
Fig 7 UV-Vis diffuse reflection spectra of the pure TiO2 and TiO2/MoS2 composites with different amount of MoS2.
Fig 8 UV-Vis diffuse reflection spectra of the pure TiO2 and Au/TiO2/MoS2 composites with different amount of MoS2.
Fig 9 Photocatalytic hydrogen evolution of the pure TiO2 and TiO2/MoS2 composites.
Fig 10 Photocatalytic hydrogen evolution of the TM6.0 and Au/TiO2/MoS2 composites.
Fig 11 Proposed mechanism for photocatalytic H2 production of ATM0.1 sample.
Fig 12 Schematic illustration of the microstructure of the ATM0.1 sample.
Fig 13 Cyclic H2 evolution curve for the ATM0.1 sample.
Fig 14 Transient photocurrent responses of the AT, ATM0.1, ATM0.5 and ATM1.0 samples. Conditions: 0.5 mol·L-1 Na2SO4 aqueous solution under xenon lamp, irradiation at 0.5 V (vs Ag/AgCl).
Fig 15 Nyquist plots of the AT, ATM0.1, ATM0.5 and ATM1.0 samples in 0.5 mol·L-1 Na2SO4 aqueous solution under xenon lamp irradiation.
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