Efficient and stable PtFe alloy catalyst for electrocatalytic methanol oxidation with high resistance to CO

Direct methanol fuel cells(DMFC) are widely considered to be an ideal green energy conversion device but their widespread applications are limited by the high price of the Pt-based catalysts and the instability in terms of surface CO toxicity in long-term operation.Herein,the PtFe alloy nanoparticles(NPs) with small particle size(~4.12 nm) supported on carbon black catalysts with different Pt/Fe atomic ratios(Pt_(1)Fe_(2)/C,Pt_(3)Fe_(4)/C,Pt_(1)Fe_(1)/C,and Pt_(2)Fe_(1)/C) are successfully prepared for enhanced anti-CO poisoning during methanol oxidation reaction(MOR).The optimal atomic ratio of Pt/Fe for the MOR is 1:2,and the mass activity of Pt_(1)Fe_(2)/C(5.40 A mg_(Pt)^(-1)) is 13.5 times higher than that of conventional commercial Pt/C(Pt/C-JM)(0.40 A mg_(Pt)^(-1)).The introduction of Fe into the Pt lattice forms the PtFe alloy phase,and the electron density of Pt is reduced after forming the PtFe alloy.In-situ Fourier transform infrared results indicate that the addition of oxyphilic metal Fe has reduced the adsorption of reactant molecules on Pt during the MOR.The doping of Fe atoms helps to desorb toxic intermediates and regenerate Pt active sites,promoting the cleavage of C-O bonds with good selectivity of CO_(2)(58.1%).Moreover,the Pt_(1)Fe_(2)/C catalyst exhibits higher CO tolerance,methanol electrooxidation activity,and long-term stability than other Pt_(x)Fe_(y)/C catalysts.

Low-temperature synthesis of apatite-type La_(9.33)Ge_6O_(26) as electrolytes with high conductivity

In the present study,high-quality apatite-type La9.33Ge6O26 powders are successfully synthesized by a facile moltensalt synthesis method（MSSM） at low temperatures,using Li Cl,Li Cl/Na Cl mixture（mass ratio 1：1） as molten salt,respectively.Experimental results indicate that the optimal mass ratio between reactant and molten salt is 1：2,and Li Cl/Na Cl mixed molten-salt is more beneficial for forming high-quality La9.33Ge6O26 powders than Li Cl individual molten-salt.Comparing with the conventional solid-state reaction method（SSRM）,the synthesis temperature of apatitetype La9.33Ge6O26 powders using the MSSM decreases more than 350℃,which can effectively avoid Ge loss in the preparation process of precursor powders.Furthermore,the powders obtained by the MSSM are homogeneous,nonagglomerated and well crystallized,which are very favorable for gaining dense pellets in the premise of avoiding Ge loss.On the basis of high-quality precursor powders,the dense and pure ceramic pellets of La（9.33）Ge6O（26） are gained at a low temperature of 1100℃ for 2 h,which exhibit higher conductivities（σ850℃（Li Cl）= 2.3 × 10^-2 S·cm^-1,σ850 ℃（Li Cl/Na Cl） = 4.9 × 10^-2 S·cm^-1） and lower activation energies（Ea（Li Cl）= 1.02 e V,Ea（Li Cl/Na Cl）= 0.99 e V） than that synthesized by the SSRM.

In-situ fabrication of ZnO nanoparticles sensors based on gas-sensing electrode for ppb-level H_(2)S detection at room temperature

The zinc oxide(ZnO)nanoparticles(NPs)sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide(H_(2)S)gas.The sphere-like ZnO NPs were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),x-ray diffraction(XRD),energy dispersive x-ray analysis(EDX),and their H_(2)S sensing performance were measured at room temperature.Testing results indicate that the ZnO NPs exhibit excellent response to H_(2)S gas at room temperature.The response value of the optimal sample to750 ppb H_(2)S is 73.3%,the detection limit reaches to 30 ppb,and the response value is 7.5%.Furthermore,the effects of the calcining time and thickness of the film on the gas-sensing performance were investigated.Both calcining time and film thickness show a negative correlation with the H_(2)S sensing performance.The corresponding reaction mechanism of H_(2)S detection was also discussed.

Construction of novel cluster-based MOF as multifunctional platform for CO_(2) catalytic transformation and dye selective adsorption

Synthetic conditions and ligands are the key structural defining factors of metal-organic frameworks(MOFs).Therefore,reasonable optimization of these aspects is considered to be an effective means for designing materials with novel structures and target functions.Herein,two novel Co(Ⅱ)-based MOFs,namely[Co(HL)(dibp)]_(n)(HL-8) and{[Co_(2)(L)(OH)(dibp)]·DMA}_n(HL-9)(H_(3)L=2',6'-dimethyl-[1,1'-biphenyl]-3,4',5-tricarboxylic acid;dibp=4,4'-di(1H-imidazol-1-yl)-1,1-biphenyl]),have been hydrothermally synthesized and structurally characterized.HL-8 crystallizes in the orthorhombic system (Pna2_(1)) with a grid layer structure,while HL-9 crystallizes in the monoclinic P2_(1)/n space group assembled through Co_(4)(OH)_(2)clusters with organic ligands.Remarkably,benefiting from the finite cage-like structure,HL-9 exhibited enhanced performance in carbon dioxide(CO_(2)) adsorption/catalytic transformation and excellent size selectivity during dye molecular adsorption process.

Synthesis of Long-Chain Oligomeric Donor and Acceptors via Direct Arylation for Organic Solar Cells

The rapid synthesis of structurally complicated electron donors&acceptors still remains a major challenge in organic solar cells(OSC).In this work,we developed a highly efficient strategy to access long-chain oligomeric donor and acceptors for OSC applications.A series of cyclopentadithiophene(CPDT)and benzothiadiazole(BT)-basedπ-conjugated oligomers,i.e.,three oligomeric acceptors(BTDT)n-IC(n=1—3)and one long-chain oligomeric donor(BTDT)4-RD,are facilely synthesized by an atom-and step-economical,and labor-saving direct C—H arylation(DACH)reaction(i.e.,C—H/C—Br cross coupling).Note that(BTDT)4-RD involving five CPDT,four BT and two rhodamine(RD)building blocks is the longest oligomeric donor in the fullerene-free OSC devices ever reported.The dependence of the structure-property-performance correlation of(BTDT)n-IC(n=1—3)and(BTDT)4-RD on theπ-conjugation lengths is thoroughly investigated by opto-electrochemical measurements,bulk heterojunction(BHJ)OSC devices and microscopies.The(BTDT)1-IC:PBDB-T and(BTDT)4-RD:Y6 BHJs achieve power conversion efficiencies of 9.14%and 4.51%,respectively.Our findings demonstrate that DACH reaction is a powerful tool to tune the opto-electronic properties and device performances by regulating the lengths ofπ-conjugated oligomers with varied numbers of repeating units.

Preparation of three-dimensional nanoporous copper foil with high specific surface area

The porous copper foil material has the advantages of ultralight and ultra-thin,and can prevent dangers such as thermal runaway and battery fire,which could be regarded as a prospective material for lithium battery cathodes.Here,a porous copper foil with a three-dimensional(3D)pore structure was synthesized by alkali and acid etching.

Magnetic, dielectric and luminescence synergetic switchable effects in molecular material [Et_(3)NCH_(2)Cl]_(2)[MnBr_(4)]

The application of multifunctional materials in various fields such as electronics and signal processors has attracted massive attention. Herein, a new organic-inorganic hybrid material [Et_(3)NCH_(2)Cl]_(2)[MnBr_(4)](1) is reported, which contains two organic amines cations and one [MnBr_(4)] tetrahedral ion. Compound 1 has a dielectric anomaly signal at 338 K, which proves its thermodynamic phase transition. The single crystal measurements at 200 K and 380 K show that the phase transition of compound 1 is caused by the thermal vibration of organic amine cations in the lattice. Moreover, compound 1 shows yellow-green luminescence under UV light irradiation. The magnetism measurements indicate that compound 1 shows switchable magnetic properties. This organic–inorganic material is a multifunctional material with dielectric, optical, and magnetic synergetic switchable effects, which expands a new direction for designing multifunctional materials.

Construction of metal-organic frameworks with unsaturated Cu sites for efficient and fast reduction of nitroaromatics:A combined experimental and theoretical study

Metal-organic frameworks(MOFs)functionalized with open metal sites(OMSs)have received widespread attention in various applications due to their fascinating electronic properties and unique interactions with guest molecules.However,rational tailoring of the coordination environment of metal nodes dur-ing the synthesis of MOFs remains a great challenge due to their tendency of saturated coordination with linkers.Herein,we reported the construction of three new MOFs featuring unsaturated Cu(Ⅱ)sites,namely[Cu(HCOO)(pzta)]_(n)(HL-1),{[Cu(PTA)0.5(pzta)(H_(2)O)]·2H_(2)O}_(n)(HL-2)and[Cu(NA)0.5(pzta)]_(n)(HL-3)(Hpzta=3-pyrazinyl-1,2,4-triazole;PTA=terephthalic acid;NA=1,4-naphthalene dicarboxylic acid),based on the mixed-linker strategy via specific selection of versatile Hpzta ligand and carboxylate ligands.Re-markably,the obtained MOFs exhibited excellent activity and good recyclability for the catalytic reduction of nitroaromatics under mild conditions(25℃and 1 atm).In particular,the complete conversion of 4-nitrophenol(4-NP)took only 30 s on HL-2,reaching a record-high TOF value compared with previously reported metal catalysts.The combined experimental and theoretical studies on HL-2 revealed that the open Cu site with positive-charged nature could improve the adsorption and subsequent electron trans-port between the substrates,and was responsible for the outstanding performance.This work shined lights on the further enhancement of performance for MOFs through rational OMSs construction.

2D Cd-MOF and its mixed-matrix membranes for luminescence sensing antibiotics in various aqueous systems and visible fingerprint identifying

The abuse of antibiotics has brought great harm to the human living environment and health,so it is extremely significant to develop an efficient and simple method to detect trace antibiotic residues in various wastewaters.Herein,a new two-dimensional(2D)Cd-based metal−organic framework(Cd-MOF,namely LCU-111)and its mixed matrix membranes(MMMs)is sifted as luminescence sensors for efficient monitoring antibiotic nitrofurazone(NFZ)in various aqueous systems and applied as visible fingerprint identifying.The LCU-111 has good selectivity,sensibility,reproducibility and anti-interference for luminescent quenching NFZ with low detection limits(LODs)of 0.4567,0.3649 and 0.8071 ppm in aqueous solution,HEPES biological buffer,and real urban Tuhai River water,respectively.Interestingly,the luminescent test papers and MMMs allow the NFZ sensing easier and more rapid by naked eyes,only with a low LOD of 0.8117 ppm for MMMs sensor.Notably,by combining multiple experiments with density functional theory(DFT)calculations,the photo-induced electron transfer(PET)quenching mechanism is further elucidated.More importantly,potential practical applications of LCU-111 for latent fingerprint visualization provide lifelike evidences for effective identification of individuals,which can be applied in criminal investigation.

Blue-shifted and naked-eye recognition of H_(2)PO_(4)- and acetylacetone based on a luminescent metal-organic framework with new topology and good stability

Fluorescence detecting both organic and inorganic analytes has aroused tremendous scientific interests, because fluorescence techniques have high sensitivity and are easy to operate. A new threedimensional(3D) MOF {[(CH_(3))_(2)NH_(2)][Zn_(3)(bbip)(BTDI)1.5(OH)]·DMF·MeOH·3H_(2)O}n(JXUST-13, bbip = 2,6-bis(benzimidazol-1-yl)pyridine and H_(4)BTDI = 5,5-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diisophthalic acid)with new 4,4,8-connceted topology has been successfully synthesized and structurally characterized. Importantly, JXUST-13 could recognize H_(2)PO_(4)-and acetylacetone(Acac) by obvious fluorescence blue shift and slight enhancement with the detection limits of 2.70 μmol/L and 0.21 mmol/L, respectively. In addition, JXUST-13 exhibits relatively good thermal stability, chemical stabilities as well as reusability, and the analytes could be distinguished by naked eye and fluorescence test paper. Remarkably, JXUST-13 is the first dual-responsive MOF sensor based on fluorescence blue shift for the detection of H_(2)PO_(4)-and Acac with good selectivity in a handy, economic, and environmentally friendly manner.

A new insight into the unique magneto-optical effect of layered perovskite(C_(6)H_(5)C_(2)H_(3)FNH_(3))_(2)MnCl_(4)

Magnet-optical materials embracing coupled magnetic and photoluminescent properties in single phase are promising in microelectronics and optoelectronic devices.However,the current research mainly focuses on traditional inorganic materials,and there are few reports on molecule materials.Recently,we synthesized an organic–inorganic hybrid complex((C_(6)H_(5)C_(2)H_(3)FNH_(3))_(2)MnCl_(4)(1)with perovskite structure.Physical measurements show that 1 not only behaves as an antiferromagnet with spin canting but also exhibits unusual fluorescent properties.Importantly,under the magnetic field at different temperatures,the luminous intensity of 1 changed,and a red-shift occurred with obviously optical hysteresis.These phenomena directly prove the existence of magneto-optical coupling in 1.More interestingly,the optical hysteresis can be observed in both low and high field,which is unprecedented in other molecular materials.Even in traditional inorganic materials,it can only be observed in strong field.This special function provides the possibility for the application of low energy consumption optoelectronic devices.

Generating electron spin qubit in metal-organic frameworks via spontaneous hydrolysis

Qubit,as the basic unit of quantum operations,has at least two quantum states for superposition.Diamond itself has no superimposable quantum states,but after injecting N atoms,the resulted nitrogenvacancy centers form excellent-performance qubits.For the same purpose,we can also obtain qubits by modifying the matrix without effective quantum states.HKUST-1({Cu_(3)(BTC)_(2)(H_(2)O)_(3)},BTC=1,3,5-benzene-tricarboxylate)with S=0 ground state is electron paramagnetic resonance(EPR)silent,so it is not a qubit candidate.However,the spontaneously hydrolyzed HKUST-1 produces dilute uncoupled Cu^(Ⅱ)ions with S=1/2.In this paper,we utilized the hydrolysis products of HKUST-1 to obtain qubits and assembled a core-shell structural HKUST-1@ZIF-8 by ZIF-8({Zn(mim)_(2)},mim=2-methylimidazole)coated over HKUST-1 for controlling the hydrolysis.The experimental results clearly show that the qubits come from hydrolyzed Cu^(Ⅱ)ions.Furthermore,the dilute uncoupled Cu^(Ⅱ)ions in this assembly can effectively reduce the decoherence of qubits.The EPR studies show that the T_(2) of this compound is 1067 ns at 10 K.

In situ synthesized homochiral dysprosium-oxo clusters with threonine Schiff bases

Chiral high-nuclearity lanthanide(4f)clusters have shown fantastic properties in various fields.However,their synthesis is still of great challenge.Herein,we report two pairs of enantiomers of highnuclearity Dy-oxo clusters synthesized through in situ strategy.They are[Dy18(^(R/S)Hftp)4(^(R/S)H_(2)btp)4(μ2-OH)_(8)(μ3-OH)20(μ6-O)(NO_(3))_(4)(μ-H_(2)O)_(8)]·[solvents](1R and 1S)and[Dy9(^(R/S)Hftp)2(^(R/S)H_(2)btp)_(2)(OAc)_(6)(μ3-OH)_(10)(H_(2)O)_(6)](OAc)·[solvents](2R and 2S),where^(R/S)Hftp2−and^(R/S)H_(2)btp^(3−)represent in situ formed 2-formyl-6-[N-(threonine)iminomethyl]-4-methylphenol and 2,6-bis[N-(threonine)iminomethyl]-4-methylphenol anions,respectively.These in situ formed clusters were endowed with not only homochirality via introducing^(R/S)Hftp2−and^(R/S)H_(2)btp^(3−)ligands,but also rich oxo-bridges by controlling the hydrolysis of Dy^(III)ions.Different anions from DyIII salts further induced structural variation between two sets of clusters.1R and 1S feature an unprecedent four-blade propeller shaped{Dy18}core,whose centered octahedral{Dy6}unit are surrounded by four triangular{Dy3}units.Strikingly,they represent the second largest chiral 4f cluster species so far.2R and 2S display a sandglass-like{Dy9}skeleton that consist of two square pyramid{Dy5}units sharing a Dy^(III)vertex.Magnetic investigation revealed possible antiferromagnetic interactions between the Dy^(III)centers in these clusters.

A Highly Efficient Luminescent Metal-Organic Framework with Strong Conjugate Unit for Sensing Small Molecules

Luminescent metal-organic frameworks(LMOFs)have become a promising class of fluorescence sensing materials,however,the multi-responsive LMOF sensors for organic compounds are rather rare.Herein,a water stable and highly efficient luminescent MOF with the formula of{[Zn(BBZB)(2,6-NDC)]-solvents}n(JXUST-10,BBZB=4,7-bis(1H-benzimidazole-1-yl)-2,1,3-benzothiadiazole and 2,6-NDC=2,6-naphthalenedicarboxylate)was constructed by the incorporation of Zn2+and two organic ligands(BBZB and 2,6-NDC)featuring the conjugate system.JXUST-10 is a three-dimensional two-fold interpenetrated framework with good fluorescent proper-ty.Based on the luminescent characteristic,JXUST-10 can be used as a multi-responsive sensor for detection of three different ana-lytes including tetracycline,benzaldehyde and uric acid via different luminescent change behaviours.Remarkably,fluorescence test paper and LED light devices are used to detect analytes through the visual change of luminescence colour of JXUST-10 from blue greenish to yellow greenish under ultraviolet light(365 nm)irradiation.Furthermore,the probable sensing mechanisms for three target analytes were also discussed.

Recent Progress in π-Conjugated Polymer-Inorganic Heterostructures for Photocatalysis

Polymer-inorganic(P-Ⅰ) soft-hard heterostructures & heterojunction photocatalysts,featured by large interfacial contact, efficient charge separation, broad light absorption and maximized redox capacity, have received great attention for their applications in energy conversion and environmental remediation. In this minireview, the classification and mechanism of P-Ⅰ heterojunctions, i.e., type-Ⅰ/Ⅱ, p-n, Z-scheme and S-scheme heterojunctions, and their preparation methods are firstly introduced. Next, the photocatalytic applications of P-Ⅰ heterojunctions, including water splitting, environmental remediation and carbon dioxide reduction, are extensively reviewed. Lastly,a brief summary and perspectives on ongoing challenges and opportunities to construct high performance P-Ⅰ soft-hard photocatalysts are intensively highlighted. We envision this review will provide a picture of the state-of-the-art achievements and promote the photocatalytic applications of P-Ⅰ heterostructures in energy conversion and environmental remediation.