Synergistic“Anchor‑Capture”Enabled by Amino and Carboxyl for Constructing Robust Interface of Zn Anode

While the rechargeable aqueous zinc-ion batteries(AZIBs)have been recognized as one of the most viable batteries for scale-up application,the instability on Zn anode–electrolyte interface bottleneck the further development dramatically.Herein,we utilize the amino acid glycine(Gly)as an electrolyte additive to stabilize the Zn anode–electrolyte interface.The unique interfacial chemistry is facilitated by the synergistic“anchor-capture”effect of polar groups in Gly molecule,manifested by simultaneously coupling the amino to anchor on the surface of Zn anode and the carboxyl to capture Zn^(2+)in the local region.As such,this robust anode–electrolyte interface inhibits the disordered migration of Zn^(2+),and effectively suppresses both side reactions and dendrite growth.The reversibility of Zn anode achieves a significant improvement with an average Coulombic efficiency of 99.22%at 1 mA cm^(−2)and 0.5 mAh cm^(−2)over 500 cycles.Even at a high Zn utilization rate(depth of discharge,DODZn)of 68%,a steady cycle life up to 200 h is obtained for ultrathin Zn foils(20μm).The superior rate capability and long-term cycle stability of Zn–MnO_(2)full cells further prove the effectiveness of Gly in stabilizing Zn anode.This work sheds light on additive designing from the specific roles of polar groups for AZIBs.

Charge storage mechanism of MOF-derived Mn2O3 as high performance cathode of aqueous zinc-ion batteries

Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most important cathode materials of ZIB.In this paper,α-Mn2O3 used as cathode of ZIB is synthesized via Metal-Organic Framework(MOF)-derived method,which delivers a high specific capacity of225 mAh g^(-1) at 0.05 A g^(-1) and 92.7 mAh g^(-1) after 1700 cycles at 2 A g^(-1).The charge storage mechanism of α-Mn2O3 cathode is found to greatly depend on the discharge current density.At lower current density discharging,the H+ and Zn2+ are successively intercalated into the α-Mn2O3 before and after the "turning point" of discharge voltage and their discharging products present obviously different morphologies changing from flower-like to large plate-like products.At a higher current density,the low-voltage plateau after the turning point disappears due to the decrease of amount of Zn2+ intercalation and the H+intercalation is dominated in α-Mn2 O3.This study provides significant understanding for future design and research of high-performance Mn-based cathodes of ZIB.

A new species in the genus Indoquedius Blackwelder(Coleoptera:Staphylinidae)from Yunnan,China

Indoquedius lii sp.nov.is described from Yunnan,China.The number of Indoquedius species has thus increased to 39.Color images of the habitus,sternites,tergite and aedeagus of this new species are included.A key to species in the genus Indoquedius of Yunnan is provided.

Carbene-catalyzed enantioselective seleno-Michael addition as access to antimicrobial active Se-containing heterocycles

Organoseleniums exhibit a diverse set of biological activities that are pivotal for drug discovery and are widely explored in synthetic chemistry and material science.While many transformations have been developed for non-enantioselective C–Se bond formations,the catalyst-controlled stereoselective preparation of chiral organoseleniums continues to be of considerable challenge.In particular,there are limited studies on the enantioselective seleno-Michael addition reactions to access chiral selenium functional molecules.Here,we disclose a carbene-catalyzed highly enantioselective nucleophilic C–Se bond construction through formal[3+3]annulations between selenocarboxamides and bromoenals,affording seleno-thiazinone products with good yields and excellent enantioselectivities.The choice of a weak inorganic base was pivotal to suppressing the unproductive racemization and decomposition of the selenium products.Notably,the catalytically generated chiral selenium-containing heterocyclic products feature remarkable antimicrobial activities that could serve as promising lead scaffolds for further agrochemical development.

Enones from aldehydes and alkenes by carbene-catalyzed dehydrogenative couplings

Enones are widely explored in synthetic chemistry as fundamental building blocks for a wide range of reactions and exhibit intriguing biological activities that are pivotal for drug discovery.The development of synthetic strategies for highly efficient preparation of enones thereby receives intense attention,in particular through the transition metal-catalyzed coupling reactions.Here,we describe a carbene-catalyzed cross dehydrogenative coupling(CDC)reaction that enables effective assembly of simple aldehydes and alkenes to afford a diverse set of enone derivatives.Mechanistically,the in situ generated aryl radical is pivotal to“activate”the alkene by forming an allyl radical through intermolecular hydrogen atom transfer(HAT)pathway and thus forging the carbon-carbon bond formation with aldehyde as the acyl synthon.Notably,our method represents the first example on the enone synthesis through coupling of“non-functionalized”aldehydes and alkenes as coupling partners,and offers a distinct organocatalytic pathway to the transition metal-catalyzed coupling transformations.

Novel optical properties and induced magnetic moments in Ru-doped hybrid improper ferroelectric Ca3Ti2O7

Hybrid improper ferroelectric Ca3Ti2O7 and Ca3Tii 9RuO.iO7 ceramics were successfully synthesized by conventional solid-state reaction method.Two strongest diffraction peaks located around 2θ=33°shifted towards the lower angle region with Ru substitution,reflecting structure variation.Grain growth and higher oxygen vacancy concentration after doping resulted in a reduction in the coercive field about 20 kV/cm.Optical bandgap estimated by UV-vis diffuse reflectance(DR)spectrum and X-ray photoelectron spectroscopy(XPS)valence band spectra showed a decreasing trend due to the existence of impurity energy level upon Ru doping,which was consistent with the results of first-principles calculations.The origin of the unexpected induced magnetic moments in Ru-dope Ca3Ti2O7 is also discussed.

Z-scheme heterojunction of SnS_(2)-decorated 3DOM-SrTiO_(3) for selectively photocatalytic CO_(2) reduction into CH4

The rapid recombination of photoinduced electron-hole pairs as well as the deficiency of high-energy carriers restricted the redox ability and products selectivity.Herein,the heterojunction of SnS_(2)-deco rated three-dimensional ordered macropores(3DOM)-SrTiO_(3) catalysts were in-situ constructed to provide transmit channel for high-energy electron transmission.The suitable band edges of SnS_(2) and SrTiO_(3) contribute to the Z-scheme transfer of photogenerated carrier.The 3DOM structure of SrTiO_(3)-based catalyst possesses the slow light effect for enhancing light adsorption efficiency,and the surface alkalis strontium is benefit to the boosting adsorption for CO_(2).The in-situ introduced SnS_(2) decorated on the macroporous wall surface of 3DOM-SrTiO_(3) altered the primary product from CO to CH4.The Z-scheme electron transfer from SnS_(2) combining with the holes in SrTiO_(3) occurred under full spectrum photoexcitation,which improved the excitation and utilization of photogene rated electrons for C02 multi-electrons reduction.As a result,(SnS_(2))3/3 DOM-SrTiO_(3) catalyst exhibits higher activity for photocatalytic CO_(2) reduction to CH4 compared with single SnS_(2) or 3 DOM-SrTiO_(3),i.e.,its yield and selectivity of CH4 are 12.5μmol g^(-1) h^(-1) and 74.9%,re spectively.The present work proposed the theoretical foundation of Z-scheme heterojunction construction for enhancing photocatalytic activity and selectivity for CO_(2) conversion.

Underpotential Deposition Preparation of Pt-loading AuNPs/Reduced Graphene Oxide and Its Catalytic Detection of Catechol

Ultralow Pt-loading Au nanoparticles have been fabricated on the surface of reduced graphene oxide （RGO） by using underpotential deposition （UPD） monolayer redox replacement process. The Pt/Au/RGO modified electrode exhibits an excellent electrocatalytic activity toward catechol and hydroquinone. Under the optimized condition, the separation of peak-to-peak between hydroquinone and catechol is 197 mV, which is wide enough to distinguish the isomers of benzenediol. Catechol is detected by the Pt/Au/RGO/GCE with a low detection limit in the presence of hydroquinone.