Dalian University of Technology

About: Dalian University of Technology is a education organization based out in Dalian, China. It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 60890 authors who have published 71921 publications receiving 1188356 citations. The organization is also known as: Dàlián Lǐgōng Dàxué.

Enhanced Photocatalytic H2O2 Production over Carbon Nitride by Doping and Defect Engineering

Abstract: Photocatalytic production of H2O2 from the reduction of O2 by semiconductor photocatalysts (e.g., graphitic carbon nitride, C3N4) has been regarded as an alternative for small-scale decentralized H...

Size- and morphology-controlled NH2-MIL-53(Al) prepared in DMF–water mixed solvents

Abstract: We present here a simple solvothermal method to fabricate metal–organic framework NH2-MIL-53(Al) crystals with controllable size and morphology just by altering the ratio of water in the DMF–water mixed solvent system without the addition of any surfactants or capping agents. With increasing the volume ratio of water in the mixed solvents, a series of NH2-MIL-53(Al) crystals with different sizes and morphologies were synthesized. The average size of the smallest crystal is 76 ± 20 nm, which provides us a simple and environmentally friendly way to prepare nanoscale MOFs. The largest BET surface area of these samples is 1882 m2 g−1 that is mainly contributed by its micropore surface area, and its corresponding micropore volume is 0.83 cm3 g−1, which have greatly extended its application in the fields of gas adsorption and postsynthetic modification. All these samples were characterized by SEM, XRD, N2 adsorption/desorption, TGA and FT-IR. Then a mechanism for the impact of the water ratio on the crystal size and morphology is presented and discussed.

Isotropic and anisotropic elasticity and yielding of 3D printed material

Abstract: 3D printing provides an innovative manufacturing method for composite materials. The mechanical property is vital for understanding the performance of 3D printed material and needs to be further studied. In this paper, the elasticity and yielding performance of acrylonitrile butadiene styrene (ABS) material created by 3D printing is investigated and the effect of printing orientation on mechanical property is quantitatively evaluated with experiments. Due to the layer by layer process procedure, 3D printed materials behave with anisotropic property. According to this characteristic, a transversely isotropic model is put forward in form of constitutive equations and is compared with isotropic model. Considering the influence of printing orientation, isotropic and anisotropic elastic and yielding model are established. The printed materials with different printing orientations are applied in uniaxial tensile tests. The material parameters, meaning the Young’s modulus, Possion’s ratio and yielding stress are determined by experiments. The results show that the printed ABS material has the Young’s modules as 2400 MPa, Poisson’s ratio as 0.37 and yielding stress as 26.84 MPa as isotropic material when the influence of printing orientation is neglected. Parameters for anisotropic model are also given and the model is recommended if the better precision concerning printing orientations is required. The obtained material parameters can be used in the mechanical simulation of 3D printed objects. The established isotropic and anisotropic models are basic findings to describe mechanical property of printed materials and can be expanded to other materials produced by 3D printing.

High surface area mesoporous nanocast LaMO3 (M = Mn, Fe) perovskites for efficient catalytic ozonation and an insight into probable catalytic mechanism

Abstract: Mesoporous nanocast perovskites (NC-LaMnO3 and NC-LaFeO3) were synthesized by nanocasting technique using SBA-15 as a template and for the first time they were used in catalytic ozonation of 2-chlorophenol. For the purpose of comparison, uncast counterpart perovskites (CA-LaMnO3 and CA-LaFeO3) as well as Mn3O4 and Fe2O3 were also prepared by conventional citric acid assisted route. Nanocast perovskites possessed high specific surface area and large pore dimensions than uncast perovskites. Catalytic activity in terms of TOC removal followed the order of NC-LaMnO3 > NC-LaFeO3 > CA-LaMnO3 > CA-LaFeO3 > Mn3O4 > Fe2O3 > O3 with 80, 68, 50, 43, 39, 33% and 25% respectively. A detailed study is conducted to discuss the mechanism of catalytic ozonation of selected NC-LaMnO3 perovskite by using organic and inorganic hydroxyl radical’s quenchers, FTIR, florescence spectroscopy, EPR, ATR-FTIR, XPS, LSV, H2O2 detection, Raman spectroscopy, TPR-H2, Rct value calculation, ozone utilization efficiency and ozone decomposition. It was found that hydroxyl radicals rather than surface peroxide, surface atomic oxygen, superoxide and singlet oxygen were the reactive oxygen species contributed to high catalytic activity. Moreover, high surface area as well as open porous structure of nanocast perovskites were believed to enhance the catalytic activity by surface reaction and easy access of reactants to the active sites.