Germylene-Fe complexes caused by heterometallic coupling and investigation into the 3d-4p bonding

The interpretation of heterometallic bonding nature is a basic work of inorganic chemistry.By means of intermetallic substitution of germylene anions with iron halide complexes CpFe(CO)_(2)I andβ-diketiminato Fe^Ⅱchloride,the ferrogermylene complexes 3a,3b and 4a were synthesized and structurally characterized.The structural and IR characterizations show the presence of the Ge←Feπbackbonding in molecules 3a,3b and 4a.The computational works on frontier molecular orbitals and their comparison of energy states confirmed thatσdonation andπbackbonding are both weak in these molecules,despite three complexes have longer Ge-Fe bonds,whose strength decreases slightly with the degressive electron density around Fe environment in a sequence from 3a,3b to 4a.

XO(X=Ti,Mn)decorated hollow multi-channel carbon sub-micro fiber networks as freestanding cathode for LieS batteries

Lithium-sulfur(Lisingle bondS)batteries are considered as one of the most promising high-energy storage devices due to the high theoretical capacity(1675 mA·h·g^(-1))and large energy density(2600 W·h·kg^(-1)).However,the poor conductivity of sulfur and“shuttle effect”of soluble polysulfide intermediates limit practical applications of Lisingle bondS batteries.Herein,four kinds of carbon sub-micro fibers with different structures were designed and prepared,the effect of structure on Lisingle bondS battery was studied.On this basis,the XO(X=Ti,Mn)decorated hollow multi-channel carbon sub-micro carbon fibers(HMCMFs)were prepared by electrospinning and carbonization.The HMCMFs can not only supply nanopores for relieving the expansion of sulfur but also served as high conductivity freestanding substrate for sulfur loading,meanwhile the decorated XO(X=Ti,Mn)can provide powerful chemical adsorption to polysulfide intermediates and limit“shuttle effect”Therefore,the TiO-HMCMFs/S composite shows high specific capacity of 900 mA·h·g^(-1)and maintain stable specific capacities up to∼600 mA·h·g^(-1)over 300 cycles at 0.1 A·g^(-1).This work offers a facile method to build efficient sulfur cathode to acquire Lisingle bondS batteries with high performance.

Carboxylated carbon nanotubes with high electrocatalytic activity for oxygen evolution in acidic conditions

Since most electrocatalysts for oxygen evolution reaction(OER),except for precious metal oxides RuO_(2) and IrO_(2),are unstable in harsh acidic solutions,it is highly desirable to develop high-performance OER electrocatalysts for acidic media,though it is still a big challenge.Herein,we report a simple strategy to produce carboxyl-enriched multiwalled carbon nanotubes(COOH-MWNTs)that exhibit stable and high electrocatalytic activities for OER in acidic solutions,showing an overpotential at a current density of 10 mA cm^(–2) and a Tafel slope as low as of 265 mV and 82 mV dec^(–1),respectively.As far as we are aware,these results represent the best OER performance for metal-free electrocatalysts,even comparable to those of RuO_(2) and IrO_(2).We have further revealed the catalytic mechanism,which involves one electron lose from the COOH-MWNTs catalyst at the beginning of the OER process to trigger H_(2)O molecule oxidation by forming peralcohol,followed by the recapture of one electron from water molecule to oxidize water and to recover the initial state for the COOH-MWNTs catalyst.The unravel of this new OER mechanism is important as it provides new insights into the crucial role of organic functional groups in electrocatalytic processes.Also,the mechanistic understanding can be used to guide the design and development of novel metalfree catalysts for acidic OER electrocatalysis and beyond.

Improving the sensitivity of DC magneto-optical Kerr effect measurement to 10^(-7)rad/√Hz

A high-sensitivity DC magneto-optical Kerr effect(MOKE)apparatus is described in this Letter.Via detailed analysis on several dominatingnoise sources,we have proposed solutions that significantly lower the MOKE noise,and a sensitivity of 1.5×10^(-7)rad/√Hz is achieved with long-term stability.The sensitivity of the apparatus is tested by measuring a wedgeshaped Ni thin film on SiO_(2)with Ni thickness varying from 0 to 3 nm.A noise floor of 1.5×10^(-8)rad is demonstrated.The possibility of further improving sensitivity to 10^(-9)rad via applying AC modulation is also discussed.