Nanjing University of Science and Technology

About: Nanjing University of Science and Technology is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 31581 authors who have published 36390 publications receiving 525474 citations. The organization is also known as: Nánjīng Lǐgōng Dàxué & Nánlǐgōng.

Assembly of hollow mesoporous nanoarchitectures composed of ultrafine Mo2C nanoparticles on N-doped carbon nanosheets for efficient electrocatalytic reduction of oxygen

Abstract: A simple method is developed to assemble Mo2C nanocrystals on the surfaces of hollow, highly conductive mesoporous nanoparticles. Diblock copolymer (PS-b-PEO) micelles are used as templates to assist in the fast complexation of molybdate (MoO42−) and polydopamine (PDA) precursors to make hollow precursor MoO42−/PDA/PS-b-PEO particles. Then these particles are carbonized to generate mesoporous N-doped carbon nanosheets riddled with ultrafine molybdenum carbide (Mo2C) nanoparticles (MMo2C/NCS). An N-doped carbon matrix serves as an electron conductor and helps to prevent the aggregation of the Mo2C nanoparticles. The Mo2C nanoparticles in turn enhance the catalytic performance for the oxygen reduction reaction (ORR). The unique mesoporous 2D nanosheet and its derived 3D hollow structure expose numerous active catalytic sites while enabling free diffusion of the electrolyte and mass transfer. Based on these properties, MMo2C/NCS show enhanced catalytic activity for the ORR.

Metallic liquids and glasses: atomic order and global packing.

Abstract: In this Letter, we have revealed the common structural behavior of metallic glasses through scrutinizing the evolution of pair distribution functions from metallic liquids to glasses and statistically analyzing pair distribution functions of 64 metallic glasses It is found that the complex atomic configuration in metallic glasses can be interpreted globally as a combination of the spherical-periodic order and local translational symmetry The implications of our study suggest that the glass transition could be visualized mainly as a process involving in local translational symmetry increased from the liquid to glassy states

High-speed transport-of-intensity phase microscopy with an electrically tunable lens.

Abstract: We present a high-speed transport-of-intensity equation (TIE) quantitative phase microscopy technique, named TL-TIE, by combining an electrically tunable lens with a conventional transmission microscope. This permits the specimen at different focus position to be imaged in rapid succession, with constant magnification and no physically moving parts. The simplified image stack collection significantly reduces the acquisition time, allows for the diffraction-limited through-focus intensity stack collection at 15 frames per second, making dynamic TIE phase imaging possible. The technique is demonstrated by profiling of microlens array using optimal frequency selection scheme, and time-lapse imaging of live breast cancer cells by inversion the defocused phase optical transfer function to correct the phase blurring in traditional TIE. Experimental results illustrate its outstanding capability of the technique for quantitative phase imaging, through a simple, non-interferometric, high-speed, high-resolution, and unwrapping-free approach with prosperous applications in micro-optics, life sciences and bio-photonics.

Electrospun ZIF-based hierarchical carbon fiber as an efficient electrocatalyst for the oxygen reduction reaction

Abstract: The inherently granular nature of nitrogen and metal co-doped carbons derived from metal–organic frameworks (MOFs) hinders their practical application in the oxygen reduction reaction (ORR). In this work, we have developed a novel N, Co-containing MOF-based hierarchical carbon fiber as an ORR catalyst. The products (ZCP-CFs) are synthesized by the incorporation of a Zn, Co-zeolitic imidazolate framework (Zn, Co-ZIF) with electrospun Co2+/poly(acrylonitrile) fiber, followed by carbonization and acid leaching treatment. The effects of the pyrolysis temperature and precursor on the ORR performance of the final samples were systematically studied. The results indicated that the material prepared at 900 °C (ZCP-CFs-9) was identified as the best ORR catalyst in the series of samples. Further comparison among samples obtained from different catalyst precursors also demonstrated the superior performance of ZCP-CFs-9, with its more positive half-wave potential (−0.135 V vs. Ag/AgCl), higher diffusion-limited and kinetic-limiting currents and higher selectivity (number of electrons transferred n = ∼3.97) than Zn, Co-ZIF derived carbon and Zn, Co-ZIF free carbon fiber. Notably, the ZCP-CFs-9 catalyst exhibited very close activity to a commercial Pt/C catalyst with better durability and stronger tolerance to methanol crossover. The remarkable ORR performance may be ascribed to its unique structure, such as its large surface area and hierarchical porosity, the dispersed and protected Co nanoparticles and N functionalized carbon framework, as well as the abundant graphitic carbon and its 1D fibrous structure. Considering the diversity of MOFs and electrospinnable polymer precursors, this strategy may be further extended to other MOF-based carbon fibers for energy storage and conversion.