Yanshan University

About: Yanshan University is a education organization based out in Qinhuangdao, China. It is known for research contribution in the topics: Microstructure & Control theory. The organization has 19544 authors who have published 16904 publications receiving 184378 citations. The organization is also known as: Yānshān dàxué.

A highly nitrogen-doped porous graphene – an anode material for lithium ion batteries

Abstract: A novel nitrogen-doped porous graphene material (NPGM) was prepared by freeze-drying a graphene/melamine–formaldehyde hydrogel and subsequent thermal treatment. The use of melamine–formaldehyde resin as a cross-linking agent and nitrogen source enhances the nitrogen content. NPGM possesses a hierarchical porous structure, a large Brunauer–Emmett–Teller surface area (up to 1170 m2 g−1), and a considerable nitrogen content (5.8 at%). NPGM displays a discharge capacity of 672 mA h g−1 at a current density of 100 mA g−1 when used as an anode material for lithium ion batteries, much higher than that observed for a nitrogen-free graphene porous material (450 mA h g−1). The NPGM electrode also possesses superior cycle stability. No capacity loss was observed even after 200 charge/discharge cycles at a current density of 400 mA g−1. The enhanced electrochemical performance is attributed to nitrogen doping, high specific surface area, and the three-dimensional porous network structure.

Theoretical Insights and the Corresponding Construction of Supported Metal Catalysts for Highly Selective CO2 to CO Conversion

Abstract: Exploration of highly selective catalysts for the reverse water-gas shift reaction, which can serve as a pivotal stage of transitioning abundant CO2 resources into chemicals or fuels, still remains a great challenge. Here, we offer a guideline about this matter on the basis of exploration of the evolution of the main intermediates during CO2 hydrogenation over a library of supported metal catalysts with density functional calculations. We identified that a high selectivity toward this reaction was correlated with the energy difference between the dissociation barrier and the desorption energy of metal carbonyls over supported metal catalysts. Generally, decreasing the coordination number of metal sites to single-atom or moving supported metals to the lower right corner in the transition-metal series hindered the carbonyl dissociation but improved CO desorption, giving rise to increased CO selectivity. Furthermore, the above strategies were truly confirmed by measuring the catalytic performance that occurr...

Fabrication of Hierarchical Layer-by-Layer Assembled Diamond-based Core-Shell Nanocomposites as Highly Efficient Dye Absorbents for Wastewater Treatment

Abstract: The effective chemical modification and self-assembly of diamond-based hierarchical composite materials are of key importance for a broad range of diamond applications. Herein, we report the preparation of novel core-shell diamond-based nanocomposites for dye adsorption toward wastewater treatment through a layer-by-layer (LbL) assembled strategy. The synthesis of the reported composites began with the carboxyl functionalization of microdiamond by the chemical modification of diamond@graphene oxide composite through the oxidation of diamond@graphite. The carboxyl-terminated microdiamond was then alternatively immersed in the aqueous solution of amine-containing polyethylenimine and carboxyl-containing poly acrylic acid, which led to the formation of adsorption layer on diamond surface. Alternating (self-limiting) immersions in the solutions of the amine-containing and carboxyl-containing polymers were continued until the desired number of shell layers were formed around the microdiamond. The obtained core-shell nanocomposites were successfully synthesized and characterized by morphological and spectral techniques, demonstrating higher surface areas and mesoporous structures for good dye adsorption capacities than nonporous solid diamond particles. The LbL-assembled core-shell nanocomposites thus obtained demonstrated great adsorption capacity by using two model dyes as pollutants for wastewater treatment. Therefore, the present work on LbL-assembled diamond-based composites provides new alternatives for developing diamond hybrids as well as nanomaterials towards wastewater treatment applications.