Beijing University of Technology

About: Beijing University of Technology is a education organization based out in Beijing, Beijing, China. It is known for research contribution in the topics: Microstructure & Computer science. The organization has 31929 authors who have published 31987 publications receiving 352112 citations. The organization is also known as: Běijīng Gōngyè Dàxué & Beijing Polytechnic University.

Inverted Design for High-Performance Supercapacitor Via Co(OH)2-Derived Highly Oriented MOF Electrodes

Abstract: Metal organic frameworks (MOFs) are considered as promising candidates for supercapacitors because of high specific area and potential redox sites. However, their shuffled orientations and low conductivity nature lead to severely-degraded performance. Designing an accessibly-manipulated and efficient method to address those issues is of outmost significance for MOF application in supercapacitors. It is the common way that MOFs scarify themselves as templates or precursors to prepare target products. But to reversely think it, using target products to prepare MOF could be the way to unlock the bottleneck of MOFs' performance in supercapacitors. Herein, a novel strategy using Co(OH)2 as both the template and precursor to fabricate vertically-oriented MOF electrode is proposed. The electrode shows a double high specific capacitance of 1044 Fg−1 and excellent rate capability compared to MOF in powder form. An asymmetric supercapacitor was also fabricated, which delivers a maximum energy density of 28.5 W h kg−1 at a power density of 1500 W kg−1, and the maximum of 24000 W kg−1 can be obtained with a remaining energy density of 13.3 W h kg−1. Therefore, the proposed strategy paves the way to unlock the inherent advantages of MOFs and also inspires for advanced MOF synthesis with optimum performance.

Single-atom site catalysts for environmental catalysis

Abstract: In recent decades, the environmental protection and long-term sustainability have become the focus of attention due to the increasing pollution generated by the intense industrialization. To overcome these issues, environmental catalysis has increasingly been used to solve the negative impact of pollutants emission on the global environment and human health. Supported platinum-metal-group (PGM) materials are commonly utilized as the state-of-the-art catalysts to eliminate gaseous pollutants but large quantities of PGMs are required. By comparison, single-atom site catalysts (SACs) have attracted much attention in catalysis owing to their 100% atom efficiency and unique catalytic performances towards various reactions. Over the past decade, we have witnessed burgeoning interests of SACs in heterogeneous catalysis. However, to the best of our knowledge, the systematic summary and analysis of SACs in catalytic elimination of environmental pollutants has not yet been reported. In this paper, we summarize and discuss the environmental catalysis applications of SACs. Particular focus was paid to automotive and stationary emission control, including model reaction (CO oxidation, NO reduction and hydrocarbon oxidation), overall reaction (three-way catalytic and diesel oxidation reaction), elimination of volatile organic compounds (formaldehyde, benzene, and toluene), and removal/decomposition of other pollutants (Hg0 and SO3). Perspectives related to further challenges, directions and design strategies of single-atom site catalysts in environmental catalysis were also provided.

New strategies for some issues of numerical manifold method in simulation of crack propagation

Abstract: SUMMARY Aiming to solve, in a unified way, continuous and discontinuous problems in geotechnical engineering, the numerical manifold method introduces two covers, namely, the mathematical cover and the physical cover. In order to reach the goal, some issues in the simulation of crack propagation have to be solved, among which are the four issues to be treated in this study: (1) to reduce the rank deficiency induced by high degree polynomials as local approximation, a new variational principle is formulated, which suppresses the gradient-dependent DOFs; (2) to evaluate the integrals with singularity of 1/r, a new numerical quadrature scheme is developed, which is simpler but more efficient than the existing Duffy transformation; (3) to analyze kinked cracks, a sign convention for argument in the polar system at the crack tip is specified, which leads to more accurate results in a simpler way than the existing mapping technique; and (4) to demonstrate the mesh independency of numerical manifold method in handling strong singularity, a mesh deployment scheme is advised, which can reproduce all singular locations of the crack with regard to the mesh. Corresponding to the four issues, typical examples are given to demonstrate the effectiveness of the proposed schemes. Copyright © 2013 John Wiley & Sons, Ltd.