Browsing by Author "Xu, Hui"

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    Cryo-mediated exfoliation and fracturing of layered materials into 2D quantum dots
    (AAAS, 2017) Wang, Yan; Liu, Yang; Zhang, Jianfang; Wu, Jingjie; Xu, Hui; Wen, Xiewen; Zhang, Xiang; Tiwary, Chandra Sekhar; Yang, Wei; Vajtai, Robert; Zhang, Yong; Chopra, Nitin; Odeh, Ihab Nizar; Wu, Yucheng; Ajayan, Pulickel M.
    Atomically thin quantum dots from layered materials promise new science and applications, but their scalable synthesis and separation have been challenging. We demonstrate a universal approach for the preparation of quantum dots from a series of materials, such as graphite, MoS2, WS2, h-BN, TiS2, NbS2, Bi2Se3, MoTe2, Sb2Te3, etc., using a cryo-mediated liquid-phase exfoliation and fracturing process. The method relies on liquid nitrogen pretreatment of bulk layered materials before exfoliation and breakdown into atomically thin two-dimensional quantum dots of few-nanometer lateral dimensions, exhibiting size-confined optical properties. This process is efficient for a variety of common solvents with a wide range of surface tension parameters and eliminates the use of surfactants, resulting in pristine quantum dots without surfactant covering or chemical modification.
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    Metallic 1T-TiS2 nanodots anchored on a 2D graphitic C3N4 nanosheet nanostructure with high electron transfer capability for enhanced photocatalytic performance
    (Royal Society of Chemistry, 2017) Liu, Yang; She, Xiaojie; Zhang, Xiaoni; Liang, Chenglu; Wu, Jingjie; Yu, Peng; Nakanishi, Yusuke; Xie, Banghu; Xu, Hui; Ajayan, Pulickel M.; Yang, Wei
    Photocatalysis is one of the most promising technologies for solar energy conversion. With the development of photocatalysis technology, the creation of low-dimensional structure photocatalysts with improved properties becomes more and more important. Metallic 1T-TiS2 nanodots with a low-dimensional structure were introduced into environmentally friendly two-dimensional g-C3N4 (2D-C3N4) nanosheets by a solvothermal method. It was found that the ultrathin TiS2 nanodots were uniformly anchored on the surface of the 2D-C3N4. The effective suppression of electron–hole recombination was realized due to the addition of the intrinsic metallic property of 1T-TiS2 in the prepared nanocomposite. The 5 wt% TiS2/2D-C3N4 nanocomposite exhibited the best photocatalytic performance and the degradation rate towards RhB was ca. 95% in 70 min, which showed an improvement of ca. 30% in comparison with 2D-C3N4. The results indicate that the obtained TiS2/2D-C3N4 nanocomposite is a promising photocatalyst for practical applications.