Tuning the selectivity of CO_(2)conversion to CO on partially reduced Cu_(2)O/ZnO heterogeneous interface

The development of stable and efficient low-cost electrocatalysts is conducive to the industrialization of CO_(2).The synergy effect between the heterogeneous interface of metal/oxide can promote the conversion of CO_(2).In this work,Cu_(2)O/ZnO heterostructures with partially reduced metal/oxide heterointerfaces in Zn plates(CZZ)have been synthesized for CO_(2)electroreduction in different cationic solutions(K^(+)and Cs^(+)).Physical characterizations were used to demonstrate the heterojunction of Cu_(2)O/ZnO and the heterointerfaces of metal/oxide,electrochemical tests were used to illustrate the enhancement of the selectivity of CO_(2)to CO in different cationic solutions.Faraday efficiency for CO with CZZ as catalyst reaches 70.9%in K+solution(current density for CO−3.77 mA cm^(−2)and stability 24 h),and the Faraday efficiency for CO is 55.2%in Cs^(+)solution(−2.47 mA cm^(−2)and 21 h).In addition,in situ techniques are used to elucidate possible reaction mechanisms for the conversion of CO_(2)to CO in K^(+)and Cs^(+)solutions.

Structure regulated catalytic performance of gold nanocluster-MOF nanocomposites

Atomically precise gold(Au)nanoclusters(NCs)as visible light photosensitizers supported on the substrate for photoredox catalysis have attracted considerable attentions.However,eficient control of their photocatalytic activity and long-term stability is still challenging.Herein,we report a coordination-assisted self-assembly strategy in combination with electrostatic interaction to sandwich Au2:(Capt)18(abbreviated as AU25,Capt=captopril)NCs between an inner core and an outer shell made of UiO-66,denoted as UiO-66@Au25@UiO-66.Notably,the sandwich-like nanocomposite displays significantly enhanced catalytic activity along with an excellent stability when used in the selective photocatalytic aerobic oxidation of sulfide to sulfoxide.As comparison,AU25 NCs simply located at the outer surface or insider matrix of UiO-66(short as Au2/UiO-66 and AU2s@UiO-66)show poor stability and low conversion,respectively.This structure regulated difference in the catalytic performances of three nanocomposites is assigned to the varied distribution of active sites(Au NCs)in metal-organic frameworks(MOFs).This work offers the opportunity for application of nanoclusters in catalysis,energy conversion and even biology.

Recent progress in all-inorganic metal halide nanostructured perovskites:Materials design,optical properties,and application

Low-dimensional all-inorganic metal halide perovskite(AIMHP)materials,as a new class of nanomaterials,hold great promise for various optoelectronic devices.In the past few years,tremendous progress has been achieved in the development of efficient and stable AIMHP nanomaterials for optical property studies and related applications.Here,we offer a critical overview on the unique merits and the state-of-the-art design of AIMHP using different composition strategies.Then,the effects of material compositions,dimensionality,morphologies and structures on optical properties are summarized.We also comprehensively present recent advances in the development AIMHP nanomaterials for practical applications including solar cells,light-emitting diodes,lasers and photodetectors.Lastly,the critical challenges and future opportunities in this emerging field are highlighted.

Carbon-supported layered double hydroxide nanodots for efficient oxygen evolution: Active site identification and activity enhancement

In this study,we developed a novel confinement-synthesis approach to layered double hydroxide nanodots(LDH-NDs)anchored on carbon nanoparticles,which formed a three-dimensional(3D)interconnected network within a porous carbon support derived from pyrolysis of metal-organic frameworks(C-MOF).The resultant LDH-NDs@C-MOF nonprecious metal catalysts were demonstrated to exhibit super-high catalytic performance for oxygen evolution reaction(OER)with excellent operation stability and low overpotential(-230 mV)at an exchange current density of 10 mA·cm^(-2).The observed overpotential for the LDH-NDs@C-MOF is much lower than that of large-sized LDH nanosheets(321 mV),pure carbonized MOF(411 mV),and even commercial RuO_(2)(281 mV).X-ray absorption measurements and density functional theory(DFT)calculations revealed partial charge transfer from Fe^(3+)through an O bridge to Ni^(2+)at the edge of LDH-NDs supported by C-MOF to produce the optimal binding energies for OER intermediates.This,coupled with a large number of exposed active sides and efficient charge and electrolyte/reactant/product transports associated with the porous 3D C-MOF support,significantly boosted the OER performance of the LDH-ND catalyst with respect to its nanosheet counterpart.Apart from the fact that this is the first active side identification for LDH-ND OER catalysts,this work provides a general strategy to enhance activities of nanosheet catalysts by converting them into edge-rich nanodots to be supported by 3D porous carbon architectures.

Optical Activity of Chiral Metal Nanoclusters

CONSPECTUS:The emerging chirality in nanomaterials represents one of the most dynamic areas in modern science.Although many novel chiral nanomaterials have been reported,the origin of their chirality and related optical activity have been not unveiled unambiguously.Thanks to the fast development of noble metal cluster chemistry,the structures of many chiral nanoclusters(CNCs)have been precisely determined and their chirality origin has been decoded as four different levels including chiral ligand,helix staple motif,asymmetry metal kernel,and chiral arrangement of organic ligands.Generally,the strong optical activity associated with the electron transitions of the noble metal core is popularly reported among CNCs protected by chiral ligands,following the so-called“outside-in”chirality transfer theory,namely,from organic ligand to metal core.Exceptionally,inherent chiral structures are discerned inside CNCs consisting of achiral ligands,such as the helix staples found in Au38(SR)24 and Au102(SR)44(SR=thiolate)and the chiral metal kernel existing in Au20(PP3)4Cl4(PP3=tris(2-(diphenylphosphino)ethyl)phosphine).These chiral nanostructures induce distinct optical activity and even present reversed chirality transformation in the case of Au38(SR)24(i.e.,from chiral core structure to organic ligand).In the past decade,our group has carried out extensive research work on preparation,enantioseparation,optical activity,and application of chiral inorganic nanostructures.As representatives,enantiopure right-handed and left-handed Au20(PP3)4Cl4 clusters of intrinsic kernel chirality were acquired through an innovative supramolecular self-assembly method and their circular dichroism(CD)feature involving only the metal core was systematically studied;Au3[R/S-Tol-BINAP]3Cl(R/S-Tol-BINAP:R/S-2,2′-bis(di-p-tolylphosphino)-1,1′-binaphthyl)clusters with the smallest metal-atom number among the reported CNCs were designed and synthesized by using the privileged chiral Tol-BINAP ligand,which exhibited not only strongly enhanced CD signal also remarkable circular polarized luminescence(CPL)response as selfassembled into monodispersed nanocubes.In this Account,we aim at reviewing the fast development of CNCs featuring strong chiral attributes and optical activity.We will briefly introduce the preparation methods of CNCs,such as direct synthesis,ligand exchange,and enantioseparation.In the following parts,the commonly used tools for characterizing the chirality of CNCs are summarized,including CD,vibrational circular dichroism(VCD),CPL,single X-ray diffraction,nuclear magnetic resonance(NMR),and theoretical prediction.Then,the optical activity of CNCs will be systematically discussed,especially their CD,VCD,and CPL activity along with their chirality origin.Finally,future strategies for fabricating CNCs possessing strong optical activity as well as potential chirality-related applications will be proposed.We believe that this Account will trigger more research interest to not only study the amazing optical activity of CNCs but also employ them in many fields.