Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China

Harbin China, China

Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China

Harbin China, China
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Yin Y.,Harbin Institute of Technology | Zhang Y.,Harbin Institute of Technology | Gao T.,Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China | Yao T.,Harbin Institute of Technology | And 9 more authors.
Advanced Materials | Year: 2017

MoSe2 is a promising earth-abundant electrocatalyst for the hydrogen-evolution reaction (HER), even though it has received much less attention among the layered dichalcogenide (MX2) materials than MoS2 so far. Here, a novel hydrothermal-synthesis strategy is presented to achieve simultaneous and synergistic modulation of crystal phase and disorder in partially crystallized 1T-MoSe2 nanosheets to dramatically enhance their HER catalytic activity. Careful structural characterization and defect characterization using positron annihilation lifetime spectroscopy correlated with electrochemical measurements show that the formation of the 1T phase under a large excess of the NaBH4 reductant during synthesis can effectively improve the intrinsic activity and conductivity, and the disordered structure from a lower reaction temperature can provide abundant unsaturated defects as active sites. Such synergistic effects lead to superior HER catalytic activity with an overpotential of 152 mV versus reversible hydrogen electrode (RHE) for the electrocatalytic current density of j = -10 mA cm-2, and a Tafel slope of 52 mV dec-1. This work paves a new pathway for improving the catalytic activity of MoSe2 and generally MX2-based electrocatalysts via a synergistic modulation strategy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Cui Z.,Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China | Bai X.,Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China | Liu Y.,Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China | Li S.,Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China
Applied Organometallic Chemistry | Year: 2017

Palladium nanocrystals with a variety of shapes have received particular interest in recent years due to their unique properties in catalysis. Herein, Pd concave nanocubes with high-index facets (Pd-CNs) was synthesized by a simple water-based route without seeds using L-ascorbic acid (AA) as the reduction agent in the presence of CTAB. X-ray diffraction and transmission electron microscopy were employed to demonstrate the formation of concave structures with high-index facets of the Pd-CNs with an average size of 17.5 nm. The as-prepared Pd-CNs presented significantly higher catalytic activity than commercial Pd/C (an average particle size of 4.7 nm) in the electro-oxidation of methanol, but exhibited weaker property in Suzuki coupling reaction, which provided an evidence for the effect of shape and size on different reactions. © 2017 John Wiley & Sons, Ltd.


Wang D.,Harbin University of Science and Technology | Liu P.,Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China | Qu C.,Heilongjiang Institute of Technology | Liu L.,Harbin University of Science and Technology | And 4 more authors.
Polymers for Advanced Technologies | Year: 2015

A series of novel modifiers for bismaleimide, bearing propenyl and phenoxy functional groups has been synthesized. Structural information of the monomers was obtained through Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Polymerization characteristics demonstrate that all four systems prepared have a cure temperature below 210°C. This remarkably lower cure temperature compared to that of other polymerization reactions involving diallyl bisphenol A and bismaleimide (DBMI) originates from propenyl groups being present in the structures as well as their larger free volume. The rheological behaviors leading to low melt viscosities and the wide process window of the prepolymer are particularly suitable characteristics for the production of performance resin-based composite materials via resin transfer molding processes. The dynamic mechanical analysis of the materials reveals glass transition temperatures in a range between 260°C and 293°C. Thermal stabilities show a 5% weight loss at temperatures ranging from 363°C to 428°C with the production of char ranging from 38.5% to 57.6% at 800°C under nitrogen. The latter is a clear indication for the excellent thermal stabilities featured by the cured resins. Furthermore, the dielectric properties exhibit a significantly lower dielectric constant and dissipation factors of the propenyl-modified cured systems compared to those of DBMI resins at 10GHz. © 2015 John Wiley & Sons, Ltd.


Liu Y.,Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China | Bai X.,Institute of Petrochemistry Heilongjiang Academy of science Harbin 150040 China
Applied Organometallic Chemistry | Year: 2016

Palladium nanoparticles supported on activated carbon were prepared by argon glow discharge plasma reduction (Pd/C-P) without any chemical reducing agents and protective agents. The as-prepared Pd/C-P catalyst was characterized using nitrogen adsorption-desorption, X-ray diffraction and transmission electron microscopy analyses. The results showed that the palladium nanoparticles reduced by plasma are well dispersed with a smaller particle size than commercial Pd/C. Pd/C-P exhibited a high catalytic activity in Suzuki and Heck coupling reactions. Moreover, there was no obvious loss of catalytic activity even after eight repeated cycles, showing good reactivity and recyclability. © 2016 John Wiley & Sons, Ltd.

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