Yufen Gu

In this work, a novel dual Z-scheme CdS/Ag₂MoO₄/β-Bi₂O₃ (CAB) composite heterojunction was synthesized, with the ultrafine CdS nanoparticles decorating two different-sized particles. In the beginning, the synergistic effect between BO and AMO makes the 10% Ag₂MoO₄/β-Bi₂O₃ (10AB) photocatalyst exhibit an optimal degradation efficiency of 87.1% for methylene blue (MB) of 10 mg·L⁻¹ within 60 min; furthermore, its photocatalytic activity was enhanced by incorporating CdS nanoparticles on the surface of the AB heterojunction. The results showed that the 25% CdS/10% AMO/BO (25C10AB) composite achieved a maximum MB degradation efficiency of 99%. Optical and photoluminescence measurements showed that the dual Z-scheme CAB heterojunction has high crystallinity and efficient charge carrier migration and separation, which makes the samples more efficient for removing pollutants. Theoretical studies (DFT/FEM calculations) were performed to better understand the migration direction of e⁻ and h⁺ in the photocatalytic degradation mechanism. This work provides a feasible approach to obtaining an efficient heterojunction composite photodegradation catalyst.

Morphology of photocatalyst has attracted many attentions due to its significant effect on photocatalytic properties. Herein, the effects of hydrothermal reaction conditions including time, temperature, and pH value on the morphology evolution as well as on the photocatalytic performance of SrMoO ₄ were investigated in detail. It was found that SrMoO ₄ had self‐assembled dual morphologies (spherical and dumbbell shape) under the specific reaction conditions with time=24 h, temperature=200 °C, and pH=6.13. In order to enhance its photocatalysis further, the silver nanoparticles (Ag‐NPs) were well‐dispersed uniform on the surface of as‐prepared samples to obtain Ag‐NPs/SrMoO ₄ composites by photoreduction method. It was determined that 3 %Ag‐NPs/SrMoO ₄ had the first‐class photocatalytic performance ( η =83.7 %, k _app =0.05229 min ^‐1 ) for the photodegradation of MB dye, which is ∼2.52 times that of the bare SrMoO ₄ with dual morphology ( η =51.9 %, k _app =0.02078 min ⁻¹ ) by comparison with the apparent first‐order reaction rate constants. The photocatalytic performance was promoted by high efficiency of photo‐induced carriers’ separation based on the effect of Localized Surface Plasmon Resonance (LSPR) of well‐dispersed Ag‐NPs.

In this work, a simple chemical co‐precipitation method was employed to prepare a series of excellent Z‐type SrWO ₄ @Bi ₂ WO ₆ (SWO@BWO) heterojunction composites, in which SrWO ₄ was successfully assembled on Bi ₂ WO ₆ nanosheets. The outstanding separation efficiency of photo‐generated carriers (e ⁻ /h ⁺ ) originated from synergetic effect of semiconductor heterojunctions under simulated sunlight effectively improved photocatalytic activity, resulting in a more prominent performance for organic dyestuff degradation compared with its counterparts. Based on the photocatalytic degradation of Methylene blue (MB) experiment, coming to a conclusion is that 10wt %SWO@BWO composite (η=92.9 % for 50 min) has the prominent photocatalytic activity. The photocatalytic performance of 10wt %SWO@BWO composite is 6.36 and 2.6 times as high as that of bare SWO and BWO, respectively. This composite also has better degradation performance for Tetracycline Hydrochloride (TC) and Tetrabromobisphenol A (TBBPA). According to the active species capture experiment, ^. OH are dominant in the degradation process of MB, and role of h ⁺ and ^. O ₂ ⁻ is also indispensable. Our research provides a simple approach for establishing Z‐scheme heterojunction photocatalysts with great photocatalytic performance.

Here, the novel Ag 2 MoO 4 /Bi 2 WO 6 ( AMO/BWO ) heterojunction composite photocatalysts were synthesized by a two-step method (co-precipitation method + hydrothermal method) and characterized by a variety of characterization techniques including XRD, XPS, SEM, TEM, UV-vis DR spectroscopy, PL spectroscopy and FTIR spectroscopy, as well as EIS analyses, and photocurrent response for confirming the formation of Z-type heterojunctions. The generation and transfer of electron/holes in the AMO/BWO heterojunctions excited by simulated sunlight were analyzed. Under simulated sunlight, the photocatalytic performance of AMO/BWO composites were studied by degradation of organic pollutants. The experimental results show that the 30wt%AMO@BWO is the best photocatalytic composite material among all samples. Due to the prolonging of lifetime of the photoexcited electrons in the CB of AMO and holes in the VB of BWO, these carriers are more effective to participate in photodegradation reactions. An electron/hole transfer mechanism of the Z-scheme heterojunctions is proposed to illustrate the enhanced photodegradation performance of the AMO/BWO composite samples.