Two-dimensional (2D) BiVO 4 nanosheets (NSs), featuring distinctive chemical properties and dangling-bond-rich surfaces, are promising for developing high-performance gas sensors. However, the previously reported 2D BiVO 4 NSs-based devices suffer from a low responsivity and poor selectivity. Here, catalytic metal (Pt) nanoparticles (NPs) are functionalized on the surface of BiVO 4 NSs to improve the sensing ability. Comparative investigations verify the significant enhancement in acetone sensing after Pt modification. The Pt NPs-loaded BiVO 4 exhibits a response of 12.5–100 ppm acetone, which is 3.2 times higher than that of pure BiVO 4 sensor. Besides, the Pt-BiVO 4 sensor possesses better selectivity and lower detection limit. From both the experimental results and density functional theory (DFT) calculation, the effects of Pt modification are elucidated as a synergy of chemical and electronic sensitization. The loading of Pt benefits the thickening of electron depletion layer , and accumulating and activating the acetone molecules, which accelerate the reaction between acetone and chemisorbed oxygen species, resulting in enhanced sensing performance. This work gives deep insights into the effects of noble metal modification on metal oxide-based sensing material and could serve as a guideline for further designing novel high-performance sensing materials.
Photocatalytic methane conversion is a sustainable approach to transform methane under mild conditions into its value-added derivatives for the petrochemical industry. However, obtaining high productivity and selectivity of desired products still remains a great challenge. In this work, high-efficiency Fe-doped two-dimensional BiVO4 nanosheets have been synthesized and evaluated for photocatalytic methane conversion with H2O, O2 or H2O2 as the oxidizer. The Fe-doped and undoped samples were obtained by hydrothermal synthesis using 3-dodecylbenzenesulfonate (SDBS) as the morphology-directing agent, and examined by XRD, SEM, EDS, TEM, XPS, UV-DRS and BET characterization techniques. The replacement of some Bi3+ with Fe3+ was a successful approach to enhance the photoexcitation process and the adsorption properties of BiVO4, resulting in an improvement in the yield of methyl oxygenates. Complete selectivity of methyl oxygenates (CH3OH and CH3OOH) was achieved, and the yield reached 217.6 μmol gcat−1 h−1 in 2 h under visible light irradiation under mild conditions over 1.0 wt% Fe-doped BiVO4 nanosheets in the presence of H2O2, outperforming most reported studies on this reaction. This work provides new insight into the choice of a suitable oxidizer for methane conversion in the BiVO4 photocatalyst system by projecting H2O2 as the relevant oxidant.
A series of hybrid films were designed and fabricated by in situ growth of Ag 2 S nanoparticles with varying content on BiVO 4 nanosheets deposited on stainless steel mesh. The formation of a p-n heterojunction between Ag 2 S and BiVO 4 enabled an extended spectral response range and facilitated the separation of charge carriers through a single directional pathway for electron transport. Exploiting these advantages, Ag 2 S/BiVO 4 composites were employed in various photocatalytic applications under simulated solar irradiation. The results demonstrated, in terms of water purification, that the composite not only possessed photocatalytic ability to degrade RhB or Cr(VI) individually but also exhibited significantly enhanced photocatalytic efficiency in simultaneously removing mixed pollutants containing RhB and Cr(VI). In terms of CO 2 conversion, Ag 2 S/BiVO 4 also displayed a stronger photocatalysis capability compared to pure BiVO 4 film. Furthermore, the immobilized Ag 2 S/BiVO 4 film exhibited improved mechanical strength and long-term stability, making it highly suitable for practical applications.
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