Xinying Yang,Jin Tian,Yang Guo,Mengyuan Teng,Haixia Liu,Tianduo Li,Pingli Lv,Xuping Wang
Zinc oxide (ZnO) possesses superior chemical and physical properties so that it can occupy an essential position in the application of nanostructures. In this paper, ZnO nano-rod arrays were synthesized by a simple one-step hydrothermal approach with the assistance of cetyl trimethyl ammonium bromide (CTAB). Exposure of the {0001} facets could be controlled by adjusting the amount of CTAB and the maximum exposure of the {0001} facets of ZnO nanorods is obtained at 1.2 g of CTAB. The photocurrent, EIS, and PL measurements support the facile charge transfer with minimum recombination of the photogenerated excitons of the ZnO nano-rod arrays obtained at 1.2 g of CTAB. Consequently, the obtained ZnO nano-rod arrays at the optimal CTAB of 1.2 g exhibit an excellent photocatalytic degradation rate of 99.7% for rhodamine B (RhB), while the degradation rate of RhB by the ZnO obtained without CTAB is only 35%.Keywords:ZnO nano-rod arrays;morphology;{0001} facets;photocatalytic activity
Two-dimensional (2D) layered metal sulfides with abundant edge sites and weak van der Waals bonds are promising materials that absorb sensing molecules at low temperatures. The introduction of defects is an effective strategy to improve the sensing performance of two-dimensional sulfide semiconductors. In this experiment, we used a facile hydrothermal method to adjust the S content of the lattice in ZnIn2S4 microflowers(MFs). And the ZnIn 2 S 4 MFs with suitable S-vacancy content were derived from the precursor with a stoichiometric ratio (Zn/In/S) of 1:2:6. These S-defect-engineered controlled growth of ZnIn 2 S 4 MFs is composed of many nanosheets(NSs) with exposed {0001} facets grown along the c-axis direction, which has a large number of S-vacancies that can serve as active sites for sensing reactions. Thus, S-vacancy-rich ZnIn 2 S 4 MFs exhibited better sensing performance for triethylamine even at the optimum operating temperature(90 ℃), including high response(1013–100 ppm), low limit of detection(1 ppm), excellent gas selectivity, and fast response(4 s). It also shows good sensitivity to lower concentrations of triethylamine at room temperature . This work demonstrates the good effect and potential of vacancy modulation in improving the performance of two-dimensional sulfide nanomaterials for low-power sensing.
Da Wang,Haodan Xu,Jun Ma,Xiaohui Lu,Jingyao Qi,Shuang Song
Novel single-crystal hexagonal MnTiO3 nanosheets with exposed {0001} facets have been synthesized via a simple one-pot hydrothermal method using NaOH as a mineralizer and tetraethylammonium hydroxide (TEAH) as a morphology controller. The intermediate morphologies of MnTiO3 nanostructures such as nanoparticles, nanowires, nanorods, and nanodiscs are trapped kinetically by adjusting the synthesis conditions. This approach enables us to elucidate the growth mechanisms of MnTiO3 nanosheets based on the tetraethylammonium cation adsorption abilities on different MnTiO3 crystal facets combined with density functional theory calculations. Dissolution and recrystallization processes are involved during the MnTiO3 crystallization. The surface-controlled MnTiO3 has been found to be effective as a catalyst for ozonation in the degradation of 4-chlorophenol (4-CP). Within typical experimental conditions (catalyst dosage = 0.3 g L–1, [4-CP]0 = 50 mg L–1, [O3] = 20 mg L–1, gas flow = 0.1 L min–1, pH 6.8, and T = 293 K), the total organic carbon (TOC) removal efficiency of 4-CP in catalytic ozonation with well-structured MnTiO3 (MnTiO3-180-10 sample) was 76.3% after 60 min, compared with only 22.1 and 38.5% TOC removal in the absence of catalyst and with uncontrolled MnTiO3 (MnTiO3-no TEAH sample), respectively. Benefiting from the high exposure percentage of {0001} facet, mixed-valences of manganese, surface hydroxyl groups, and the enrichment Lewis acid sites provided by Mn and Ti, the morphology-controlled MnTiO3 nanosheets can be applied as heterogeneous catalytic ozonation catalysts which exhibit excellent pollutant degradation. We anticipate that MnTiO3 can be a promising candidate material for the application in remediation of organic pollutants in water.
危险品化学品经营许可证（带存储）