Browsing by Author "Zheng, Z"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Capture of radioactive cesium and iodide Ions from water by using titanate nanofibers and nanotubes
    (Wiley-Blackwell, 2011-01-01) Yang, D; Sarina, S; Zhu, HW; Liu, HY; Zheng, Z; Xie, M; Smith, SV; Komarneni, S
    Radioactive Cs+ and I− ions are the products of uranium fission, and can be easily dissolved in water during an accident at a nuclear reactor, such as those that occurred at Chernobyl in 1986, at Three Mile Island in Pennsylvania in 1979, and in 2011 at Fukushima, Japan. In 2009, leaks of radioactive materials such as 137Cs and 131I isotopes also occurred during minor accidents at nuclear power stations in Britain, Germany, and the U.S. These leaks have raised concerns about exposure levels in the nearby communities because it is feared that these fission products could make their way into the food chain when present in waste water. Radioactive iodine is also used in the treatment of thyroid cancer, and, as a result, radioactive wastewater is discharged by a large number of medical research institutions.1 The wide use of radioisotopes requires effective methods to manage radioactive waste, and methods currently used are complex and extremely costly.2 Herein we demonstrate a potentially cost-effective method to remediate 137Cs+ and 131I− ions from contaminated water by using the unique chemistry of titanate nanotubes and nanofibers, which can not only chemisorb these ions but efficiently trap them for safe disposal. © 2011, Wiley-Blackwell.
  • No Thumbnail Available
    Item
    Synergistic Pt doping and phase conversion engineering in two-dimensional MoS2 for efficient hydrogen evolution
    (Elsevier, 2021-06) Li, Y; Gu, QF; Johannessen, B; Zheng, Z; Li, C; Luo, Y; Zhang, ZY; Zhang, Q; Fan, H; Luo, WB; Liu, B; Dou, SX; Liu, HK
    Molybdenum disulphide (MoS2) is proven to be a promising catalyst for hydrogen evolution reaction (HER), but the HER performance of reported MoS2-based catalysts is still limited by its poor conductivity and low density of active sites. Herein, a Pt-doped MoS2 (Pt@MoS2) catalyst is synthesized by a potential-cycling method, which introduces the Pt dopant into the MoS2 lattice and achieves partial 2H to 1T phase conversion of MoS2 simultaneously. Benefitting from the optimized geometric and electronic structure of MoS2, the Pt@MoS2 exhibits a low overpotential of 88.43 mV at 10 mA cm−2, which is decreased by two-thirds as compared to that of the pristine MoS2. A comprehensive study reveals the position and the contribution of Pt atom in electronic structure modulation of MoS2. Theoretical calculations further reveal that the S atom adjacent to the Pt in MoS2 acts as the most active site for HER, and possesses a small hydrogen adsorption free energy (∆GH*) of ~ 0.04 eV, similar to the benchmark Pt catalyst. This study opens up a new avenue for designing MoS2 and other transition metal dichalcogenide-based electrocatalysts with enhanced HER performance, as well as providing in-depth understanding on the HER mechanism in external metal-activated MoS2 catalyst. © 2021 Elsevier Ltd.