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.

Synthesis of graphene oxide anchored porous manganese sulfide nanocrystals via the nanoscale Kirkendall effect for supercapacitors

Abstract: Graphene oxide (GO) anchored porous manganese sulfide nanocrystals (MnS/GO-NH3) were obtained via a facile hydrothermal method based on the Kirkendall effect. The honeycomb-like manganese sulfide nanocrystals (40–80 nm) and the three-dimensional sandwich structure endow the MnS/GO-NH3 with high supercapacitive performance when it was used as a supercapacitor material. The MnS/GO-NH3 electrode exhibits high specific capacitance (390.8 F g−1 at 0.25 A g−1), high rate capacity (78.7% retention at 10 A g−1) and stable cycle life (81.0% retention after 2000 cycles), which are superior to those of GO anchored MnS floccules (MnS/GO) and manganese hydroxide (Mn(OH)2/GO). As a novel material for supercapacitors, the charge–discharge mechanism of the MnS/GO-NH3 composite is proposed via detailed investigation. Asymmetric supercapacitors, assembled with MnS/GO-NH3 as the positive material and activated carbon as the negative electrode, reveal a high specific capacitance (73.63 F g−1), a high energy density of 14.9 W h kg−1 at 66.5 W kg−1 and even 12.8 W h kg−1 at a high power density of 4683.5 W kg−1.

Facile preparation and high performance of wearable strain sensors based on ionically cross-linked composite hydrogels

Abstract: Flexible sensors that can respond to multiple mechanical excitation modes and have high sensitivity are of great significance in the fields of electronic skin and health monitoring. Simulating multiple signal responses to skin such as strain and temperature remains an important challenge. Therefore, new multifunctional ion-crosslinked hydrogels with toughness and conductivity were designed and prepared in this work. A chemical gel with high mechanical strength was prepared by cross-linking acrylamide with N,N′-methylene-bisacrylamide and ammonium persulfate. In addition, in order to enhance the conductive properties of the hydrogel, Ca2+, Mg2+ and Al3+ ions were added to the hydrogel during cross-linking. The double-layer network makes this ionic hydrogel show excellent mechanical properties. Moreover, the composite hydrogel containing Ca2+ can reach a maximum stretch of 1100% and exhibits ultra-high sensitivity (S p = 10.690 MPa−1). The obtained hydrogels can successfully prepare wearable strain sensors, as well as track and monitor human motion. The present prepared multifunctional hydrogels are expected to be further expanded to intelligent health sensor materials.

Facile Synthesis of Ag/Pd Nanoparticle-Loaded Poly(ethylene imine) Composite Hydrogels with Highly Efficient Catalytic Reduction of 4-Nitrophenol

Abstract: Poly(ethylene imine) (PEI) has abundant amino groups in a macromolecular chain and can be used as a graft source for metal nanocomposites, which shows excellent ability to form stable complexes with heavy metal ions. In this work, a simple and convenient method was used to make PEI into a stable hydrogel with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-N-hydroxysuccinimide and subsequently coprecipitate with silver nitrate solution or palladium chloride solution to form metal-loaded composite hydrogels. In addition, the characterizations of composite hydrogels were investigated by scanning electron microscopy, specific surface area tests (Brunauer-Emmett-Teller), X-ray photoelectron spectroscopy, and ultraviolet spectroscopy. The properties of composite hydrogels on the catalytic reduction of 4-nitrophenol were studied. The results showed that the composite hydrogels could be easily separated from the water environment, which indicated the large-scale potential application in organic catalytic degradation and wastewater treatment.