3397-16-8Relevant articles and documents
Compressive Strain Modulation of Single Iron Sites on Helical Carbon Support Boosts Electrocatalytic Oxygen Reduction
Chen, Cai,Du, Junyi,Gu, Lin,Huang, Chun-Xiang,Wang, Lingxiao,Wang, Zhiyuan,Wu, Yuen,Yang, Jia,Yang, Li-Ming,Zhang, Qinghua,Zhang, Yida,Zhang, Ying,Zheng, Xusheng,Zhou, Huang,Zhou, Xiao
, p. 22722 - 22728 (2021)
Designing and modulating the local structure of metal sites is the key to gain the unique selectivity and high activity of single metal site catalysts. Herein, we report strain engineering of curved single atomic iron-nitrogen sites to boost electrocatalytic activity. First, a helical carbon structure with abundant high-curvature surface is realized by carbonization of helical polypyrrole that is templated from self-assembled chiral surfactants. The high-curvature surface introduces compressive strain on the supported Fe?N4 sites. Consequently, the curved Fe?N4 sites with 1.5 % compressed Fe?N bonds exhibit downshifted d-band center than the planar sites. Such a change can weaken the bonding strength between the oxygenated intermediates and metal sites, resulting a much smaller energy barrier for oxygen reduction. Catalytic tests further demonstrate that a kinetic current density of 7.922 mA cm?2 at 0.9 V vs. RHE is obtained in alkaline media for curved Fe?N4 sites, which is 31 times higher than that for planar ones. Our findings shed light on modulating the local three-dimensional structure of single metal sites and boosting the catalytic activity via strain engineering.
Incorporation of graphene into photopolymerizable hydrogels of N-acyl glutanamides: Rheological and swelling behavior study of soft nanocomposite materials
Delbecq, Frederic,Endo, Hiroshi,Kono, Fumihiko,Kikuchi, Aoi,Kawai, Takeshi
, p. 1064 - 1071 (2013)
Two different respectively N-stearoyl and diacetylenic fatty acyl glutanamide were prepared and employed as both potent low molecular weight hydrogelators (LMWGs). These compounds were able to gelate water at 1.0 wt% of concentration independently of the pH. Due to the presence of two free amino groups on the extremities of the gelator, an aqueous colloidal dispersion of graphene oxide (GO) could be stabilized into the hydrogel matrix simply by ionic bonds. The inclusion of a slightly amount of GO inside the gel networks increased its natural rigidity, confirmed by rheology study. An in-situ reduction of GO afforded after treatment, a semi-transparent hydrogel containing reduced graphene (rGO) that could be easily manipulated without apparent syneresis phenomenon. When the diacetylenic type hydrogel containing GO was irradiated upon UV light, a deep blue coloration change was observed; evidence of an effective photopolymerization. In case of thermal stimulation of the resulted blue polydiacetylene (PDA) hydrogel, the material turned in a red solution precursor of a robust red (PDA) hydrogel at room temperature. This red hydrogel never displayed reversible color change and its swelling behavior was studied at different temperatures. All hydrogels were characterized by different methods such as Field-Emission Scanning Electron Microscopy (FE-SEM) for determining the homogeneity of the gel networks, but also by (FT-IR) Fourier Transform-Infrared spectroscopy and UV-visible measurement.
Circularly polarized luminescent systems fabricated by Tr?ger's base derivatives through two different strategies
Qian, Cheng,Chen, Yuan,Zhao, Qian,Cheng, Ming,Lin, Chen,Jiang, Juli,Wang, Leyong
supporting information, p. 52 - 57 (2021/02/01)
The Tr?ger's base derivative rac-TBPP was synthesized and separated into two enantiomers R2N-TBPP and S2N-TBPP by chiral column chromatography. These compounds show a strong circularly polarized luminescence with glum values of +0.0021, and -0.0025, respectively. The second way to fabricate the rac-TBPP-based CPL-active material is to co-gel the fluorescent rac-TBPP with a chiral D-glutamic acid gelator DGG by co-assembly strategy. At the molar ratio of rac-TBPP/DGG = 1:80, the glum value of the co-gel was about three times higher than the glum values of R2N-TBPP and S2N-TBPP enantiomers. Interestingly, the CPL handedness of the rac-TBPP/DGG co-gel could be adjusted effectively by changing their stoichiometric ratios.
