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.

Electropolymerized polyaniline/manganese iron oxide hybrids with an enhanced color switching response and electrochemical energy storage

Abstract: Polyaniline (PANI) nanocomposites embedded with manganese iron oxide (MnFe2O4) nanoparticles were prepared as thin films by electropolymerizing aniline monomers onto indium tin oxide (ITO) glass slides pre-spin-coated with MnFe2O4 nanoparticles. The shift of the characteristic peaks of PANI/MnFe2O4 in UV-visible absorption spectra and Fourier transform infrared (FT-IR) spectra indicates the formation of composite films and the chemical interaction between the PANI matrix and MnFe2O4 particles. A coloration efficiency of 92.31 cm2 C−1 was obtained for the PANI/MnFe2O4 nanocomposite film, higher than that of the pristine PANI film, 80.13 cm2 C−1, suggesting a synergistic effect between the MnFe2O4 particles and the PANI matrix. An enhanced areal capacitance of 4.46 mF cm−2 was also achieved in the PANI/MnFe2O4 nanocomposite film compared with 3.95 mF cm−2 in the pristine PANI film by CV at a scan rate of 5 mV s−1. The enhanced performances of the composite films were attributed to the pseudocapacitive properties of MnFe2O4 and rougher morphology caused by the embedment of MnFe2O4 particles into the PANI matrix. Finally, the sulfuric acid (H2SO4) concentration and temperature effects on the supercapacitive behavior of the pristine PANI and PANI/MnFe2O4 nanocomposite films were studied, suggesting the positive effects of decreasing H2SO4 concentration and increasing temperature in a low temperature range; higher temperatures can destroy the PANI structure and cause the degradation of PANI.

High-Indexed PtNi Alloy Skin Spiraled on Pd Nanowires for Highly Efficient Oxygen Reduction Reaction Catalysis.

Abstract: The catalytic performance of Pt-based catalysts for oxygen reduction reactions (ORR) can generally be enhanced by constructing high-index exposed facets (HIFs). However, the synthesis of Pt alloyed high-index skins on 1D non-Pt surfaces to further improve Pt utilization and stability remains a fundamental challenge for practical nanocrystals. In this work, Pd nanowires (NWs) are selected as a rational medium to facilitate the epitaxial growth of Pt and Ni. Based on the different nucleation and growth habits of Pt and Ni, a continuous PtNi alloy skin bounded with HIFs spiraled on a Pd core can be obtained. Here, the as-prepared helical Pd@PtNi NWs possess high HIF densities, low Pt contents, and optimized oxygen adsorption energies, demonstrating an enhanced ORR mass activity of 1.75 A mgPt -1 and a specific activity of 3.18 mA cm-2 , which are 10 times and 12 times higher than commercial Pt/C catalysts, respectively. In addition, the 1D nanostructure enables the catalyst to be highly stable after 30 000 potential sweeping cycles. This work successfully extends bulky high-indexed Pt alloys to core-shell nanostructures with the design of a new, highly efficient and stable Pt-based catalyst for fuel cells.