3 research outputs found

    Efficient Photoelectrochemical Hydrogen Generation from Water Using a Robust Photocathode Formed by CdTe QDs and Nickel Ion

    No full text
    Design of a novel sensitized NiO photocathode with wide visible light absorption and good stability is of great significance for photoelectrochemical hydrogen evolution. Inspired by recent reports on novel photocatalytic hydrogen evolution systems based on semiconductor quantum dots (QDs) and earth-abundant inorganic metal ion, we demonstrate the fabrication of an effective and stable photocathode by CdTe QDs and nickel ion. This photocathode showed good activity and stability for photocatalytic H<sub>2</sub> evolution (10.38 μmol) at a low overpotential of 92 mV, in which the Faradaic efficiency was almost 100% under visible light irradiation for 30 000 s. Characterized by X-ray photoelectron spectroscopy, X-ray powder diffraction and high-resolution transmission electron microscopy, the active site of photocathode in producing hydrogen by water splitting was found to be NiS@QDs. Then a possible mechanism of NiS@QDs for photoelectrochemical hydrogen evolution was proposed

    Light-Assisted Preparation of a ZnO/CdS Nanocomposite for Enhanced Photocatalytic H<sub>2</sub> Evolution: An Insight into Importance of in Situ Generated ZnS

    No full text
    In our work, ZnO/CdS hybrid photocatalysts were prepared by a simple and reproducible photodeposition method and the content of deposited CdS can be varied by irradiation time. The ZnO/CdS photocatalysts showed good photocatalytic H<sub>2</sub> evolution activities in aqueous Na<sub>2</sub>S + Na<sub>2</sub>SO<sub>3</sub> solution. When the content of CdS loading increased to 22.91% after an irradiation time of 120 min (ZnO/CdS-T120), the highest photocatalytic activity was obtained (1725 μmol g<sup>–1</sup> h<sup>–1</sup>), which was about 9.2 and 34.5 times than that of single ZnO and CdS photocatalysts. At the same time, ZnO/CdS-T120 presented stable photocatalytic ability (no noticeable degradation of H<sub>2</sub> evolution in four repeated runs in 48 h). Compared with other reported H<sub>2</sub> evolution photocatalysts, ZnO/CdS-T120 showed higher H<sub>2</sub> evolution activity and stability. Additionally, ZnO/CdS-T120 has a good natural sunlight driven H<sub>2</sub> evolution ability (2077 μmol g<sup>–1</sup> h<sup>–1</sup>). ZnS was proved to generate on ZnO/CdS-T120 surface in process of photocatalytic H<sub>2</sub> evolution based on structural analyses of recycle ZnO/CdS-T120. The formation of ZnS enhanced the photocatalytic H<sub>2</sub> evolution activity of ZnO/CdS and extended the visible light adsorption region. Meanwhile, the generation of ZnS increased the transfer interfaces for photogenerated charge carriers and consequently promoted the separation of photogenerated electrons and holes
    corecore