Gas template-assisted spray pyrolysis： A facile strategy to produce porous hollow Co3O4 with tunable porosity for high-performance lithium-ion battery anode materials

Porous hollow Co3O4 microspheres have been synthesized from a mixed cobalt nitrate and urea solution through spray pyrolysis followed by calcination at 600 ℃ in air. This porous hollow Co3O4 is assembled by nanoparticles and exhibits variable porosity depending on the amount of gas in the system. In pyrolysis process, urea continuously decomposes into gaseous components, which act as a template to control the porous structure. The amount of gas escaping from precursor droplets can directly influence the porosity of the microspheres and the size of the nanoparticles controlled by the ratio of urea to cobalt nitrate. Electrochemical measurements show that the performance of the porous hollow Co3O4 microspheres is related to the porosity and size of the nanopartides. The sample with optimal porosity delivers a high first charge capacity of 1,417.9 mAh·g^-1 at 0.2C （1C = 890 mA·g^-1）, and superior charge cycle performance of 1,012.7 mAh.g-1 after 100 cycles. In addition, the optimized material displays satisfactory rate performance of 1,012.4 mAh.g-1 at 1C after 50 cycles and 881.3 mAh·g^-1 at 2C after 300 cycles. Superior charge/discharge capacity, excellent rate performance and high yield achieved in this study is promising for the development of high-performance Co3O4 anode materials for lithium-ion batteries.

Synthesis and Characterization of Nickel(II) Complex Bearing 2,9-di-tert-butyl-1,10-phenanthroline Ligand

The complex DtbpNiCl2（Dtbp = 2,9-di-tert-butyl-1,10-phenanthroline） was synthe- sized and characterized by X-ray single-crystal structure analysis. For the complex： C20 H24 Cl2 N2 Ni CH2 Cl2, Mr = 506.95, monoclinic, space group P21 /c, a = 9.5905（3）, b = 13.7587（3）, c = 17.3364（5）, β = 94.244（2）°, V = 2281.31（11）3, Z = 4, Dc = 1.476 g/cm3, λ = 1.54184, μ = 5.606 mm-1, F（000） = 1048, S = 1.079, R = 0.0402 and wR = 0.1010 for 3223 observed reflections with I 〉 2σ（I）. In complex DtbpNiCl2, the nickel adopts a distorted tetrahedral geometry coordinated by two nitrogen atoms of Dtbp and two chlorine ions. The complex is connected by intermolecular C–H…Cl hydrogen bonds to form a 1D structure in the solid state.

Zinc Complexes Based on Organochalcogen Ligand Mbit: Syntheses, Structures and Photocatalytic Properties

The zinc complex with neutral organochalcogen ligand Mbit, [（Mbit）2Zn]（Cl O4）2（1, Mbit = 1,1＇-methylenebis（3-methyl-imidazole-2-thione））, has been synthesized and characterized. The complex has been characterized by elemental analysis, NMR and IR spectra. The molecular structure of 1 has been determined by X-ray crystallography. For the complex, C18H24Cl2N8O8S4 Zn, Mr = 744.96, triclinic, space group P1, a = 11.2923（18）, b = 11.9353（19）, c = 13.837（3） , α = 114.763（2）, β = 92.132（2）, γ = 116.039（2）°, V = 1464.6（5） 3, Z = 2, Dc = 1.689 g/cm3, λ = 1.54184 , μ = 1.363 mm-1, F（000） = 760, S = 1.098, the final R = 0.0554 and w R = 0.0.1579. Complex 1 exhibits photocatalytic activity for methyl orange（MO） degradation under UV light and shows good stability toward photocatalysis.

Solvent-Controlled Sc(OTf)_(3)-Catalyzed Ring Opening Reaction of 2-(Hetero)aryl-N-sulfonylazetidines:Synthesis of Allylic Amines/1,3-Oxazinane Derivatives

Allylic amines and 1,3-oxazinanes are valuable molecular skeletons in organic synthesis and pharmaceutical industry.A straightforward way to such two types of compounds by solvent-controlled rare-earth metal Lewis acid-catalyzed transformations of 2-(hetero)aryl-N-sulfonylazetidines:the ring-opening isomerization of azetidines to allylic amines and the annulation of azetidines with aldehydes to 1,3-oxazinanes are reported.These two reactions feature scalability,low catalyst loading,mild reaction conditions,excellent yields and regioselectivity with demonstrated utility in three-step product transformations to naftifine,abamine and abamine SG.

Tuning the local coordination environment of silver(Ⅰ) coordination networks with counterions for enhanced electrocatalytic CO_(2) reduction

Very recently, the local coordination environment of active sites has been found to strongly influence their performance in electrocatalytic CO_(2) reduction by tuning the intrinsic kinetics of CO_(2) activation and intermediate stabilization. It is imperative to elucidate the mechanism for such an influence towards the rational design of efficient catalysts;however, the complex interactions between the multiple factors involved in the system make it challenging to establish a clear structure–performance relationship. In this work, we chose ion-intercalated silver(I)-based coordination networks(AgCNs) with a well-defined structure as a model platform, which enables us to understand the regulation mechanism of counterions as the counterions are the only tuning factor involved in such a system. We prepared two isostructural Ag CNs with different intercalation ions or counterions of BF_(4)^(-) and ClO_(4)^(-)(named as AgCNs-BF_(4) and AgCNs-ClO_(4)) and found that the former has a more competitive CO_(2) electroreduction performance than the latter. AgCNs-BF_(4) achieves the highest Faradaic efficiency for CO_(2) to CO of 87.1% at-1.0 V(vs. RHE) with a higher partial current density, while AgCNs-ClO_(4) exhibits only 77.2% at the same applied potential.Spectroscopic characterizations and theoretical calculation reveal that the presence of BF_(4)^(-)is more favorable for stabilizing the COOH^(*) intermediate by weakening hydrogen bonds, which accounts for the superior activity of Ag CNs-BF_(4).

Bridging molecular photosensitizer and catalyst on carbon nanotubes toward enhanced selectivity and durability for CO_(2)photoreduction

Homogenous molecular photocatalysts for CO_(2)reduction,especially metal complex-based photosensitizer-catalyst assemblages,have been attracting extensive research interests due to their efficiency and customizability.However,their low durability and recyclability limit practical applications.In this work,we immobilized the catalysts of metal terpyridyl complexes and the photosensitizer of[Ru(bpy)3]Cl2onto the surface of carbon nanotubes through covalent bonds and electrostatic interactions,respectively,transforming the homogeneous system into a heterogeneous one.Our characterizations prove that these metal complexes are well dispersed on CNTs with a high loading(ca.12 wt.%).Photocatalytic measurements reveal that catalytic activity is remarkably enhanced when the molecular catalysts are anchored,which is three times higher than that of homogeneous molecular catalysts.Moreover,when the photosensitizer of[Ru(bpy)3]Cl2is immobilized,the side reaction of hydrogen evolution is completely suppressed and the selectivity for CO production reaches 100%,with its durability also significantly improved.This work provides an effective pathway for constructing heterogeneous photocatalysts based on rational assembly of efficient molecular photosensitizers and catalysts.

Highly efficient electrocatalytic nitrogen fixation enabled by the bridging effect of Ru in plasmonic nanoparticles

Plasmon-generated hot electrons show great potential for driving chemical reactions.The utilization efficiency of hot electrons is highly dependent on the interaction of the electronic states at the interfaces between plasmonic nanoparticles and other materials/molecules.Strong interaction can produce new hybridized electron states,which permit direct hot-electron transfer,a more efficient transfer mechanism.However,Au usually has very weak interaction with most molecules because of its inertness,which makes direct hot-electron transfer impossible.Herein,the improvement of the hot-electron transfer efficiency from Au to N_(2)is demonstrated by introducing a Ru bridging layer.Both the N_(2)fixation rate and Faradic efficiency(FE)are enhanced by the excitation of plasmons.The enhancement of the N_(2)fixation rate is found to arise from plasmon-generated hot electrons.Theoretical calculations show that the strong interaction of the Ru electronic states with the N_(2)molecular orbitals produces new hybridized electronic states,and the Ru d electrons also strongly couple with the Au sp electrons.Such a bridging role of Ru makes direct hot-electron transfer from Au to N_(2)possible,improving the FE of nitrogen fixation.Our findings demonstrate a new approach to increasing the utilization efficiency of plasmonic hot electrons for chemical reactions and will be helpful to the design of plasmonic catalysts in the future.

Living and enantiomer-selective polymerization of allene initiated by Ni complex containing chiral phosphine

A new allylnickel(II) complex([S(R)]-N-[(1 S)-2-(diphenylphosphino)-1-phenylethyl]-2-methyl-2-propanesulfinamide)(2,2,2-trifluoroacetato-k O)(p-allyl)nickel(2) was designed and prepared by using chiral phosphine. 2 was revealed to efficiently initiate the polymerization of L-and D-N-(1-(dodecylamino)-1-oxopropan-2-yl)-4-(propa-1,2-dien-1-yloxy)-benzamide(L-1 and D-1) in a living/controlled chain growth manner. Polymerization kinetics of L-1 and D-1 indicated that L-1 preferentially polymerized over the antipode D-1 by a factor of 1.9. In block copolymerization of rac-1 using the poly-L-150 as the macroinitiator, the polymerization proceeded in enantiomer-selective manner. It was found that enantiomeric excess(ee) value of the recovered monomer increased with the monomer conversion and finally reached to the maximum of 34%. These results suggest this chiral phosphine complex exhibits enantiomer-selectivity for the polymerization of chiral allene derivative monomer.