查看更多>>摘要：Smart materials that integrate multi-stimuli response,full reversibility,and dual-visual read-out channel are highly desired for anti-counterfeiting and information encryption applications.Herein,we developed a multiresponsive perchlorate terpyridyl Pt(Ⅱ)nano complex which could undergo fully reversible conversion between three forms stimulated by water or formaldehyde molecule due to the extent of Pt-Pt interaction.Meanwhile,a dual-visual channel,i.e.,the colorimetric channel changed from yellow to orange or red and the corresponding luminescent channel from orange to orange-red or red,has also been found.The weak and equivalent strength of ion-dipole interaction and hydrogen bond that generated between formaldehyde/water and Pt(Ⅱ)salt result in the easy-control reversibility between the three forms.Furthermore,by introducing different polymer matrices,1Cl·ClO4@PMMA(1Cl·ClO4:[Pt(tpy)Cl]·ClO4,tpy:2,2':6',2"-terpyridine),PMMA:poly(methyl methacrylate))and 1Cl·ClO4@PVA(PVA:polyvinyl alcohol)are successfully constructed,which exhibit different reversible behaviors since the PMMA and PVA matrix exert different influences on the strength of hydrogen-bond.Those smart Pt(Ⅱ)salt nanostructures present great potential for high-security-level anticounterfeiting application.
查看更多>>摘要：With the fast generation of electronic waste(e-waste)and the increasing depletion of metal resources,"urban mining"that can selectively recover gold from secondary resources has attracted great interest.Construction of materials with high extraction capacity and satisfying selectivity in complex aqueous-based matrices still remains challenging.Here,a novel metal-organic framework/polymer composite(Fe-BTC/poly(thioctic acid),denoted as Fe-BTC/pTA)has been newly synthesized and applied for selective gold recovery in different matrices(river water,seawater,and leaching solution of e-waste).Benefiting from the high specific surface area and suitable pore sizes as well as the rational design of active sites,the composite exhibits high adsorption capacity(920 mg/g),high removal efficiency(＞99％),fast kinetics(below 0.1 ppb within 10 min),and good applicability in complex matrices,which are better than those of most reported sulfur-containing adsorbents.Solid-state metallic gold with high purity can be effectively enriched due to the high recyclability and long-term stability of the composite.The material after adsorption can be further applied as a heterogeneous catalyst for water remediation due to the in situ generated gold nanoparticles by the redox reaction between Au(Ⅲ)ions and the S-containing groups in the composites.
查看更多>>摘要：Zinc-based aqueous rechargeable batteries have attracted extensive attention due to their low cost,safety,and environmental friendliness.However,dendrite growth and hydrogen evolution of Zn anodes limit their large-scale application.A new strategy to produce a polyacrylamide/reduced graphene oxide(PAM@rGO)molecular nanobrush coating and control Zn electrolyte interface engineering is proposed for use in highly reversible Zn plating/stripping.Hydrogen evolution is inhibited,and Zn deposition is consolidated using the rich zincophilic functional groups of the branched polyacrylamide chain and the high conductivity of rGO.Due to the synergistic effects of corrosion resistance and dendrite-free growth,PAM@rGO/Zn provides prolonged and reversible Zn plating/stripping.Density functional theory(DFT)calculations expand on homogenized nucleation.The PAM@rGO/Zn||activated carbon(AC)capacitor exhibits long cyclic stability,fast ion transfer,and minimal interfacial impedance.This study provides experimental and theoretical bases for the structural design of Zn anode.
查看更多>>摘要：The local structure of the metal single-atom site is closely related to the catalytic activity of metal single-atom catalysts(SACs).However,constructing SACs with homogeneous metal active sites is a challenge due to the surface heterogeneity of the conventional support.Herein,we prepared two Rh1/CeO2 SACs(0.5Rh1/r-CeO2 and 0.5Rh1/c-CeO2,respectively)using two shaped CeO2(rod and cube)exposing different facets,i.e.,CeO2(111)and CeO2(100).In CO oxidation reaction,the T100 of 0.5Rh1/r-CeO2 SACs is 120 ℃,while the T100 of 0.5Rh1/c-CeO2 SACs is as high as 200 ℃.Via in-situ CO diffuse reflectance infrared Fourier transform spectroscopy(CO-DRIFTS),we found that the proximity between OH group and Rh single atom on the plane surface plays an important role in the catalytic activity of Rh1/CeO2 SAC system in CO oxidation.The Rh single atom trapped at the CeO2(111)crystal surface forms the Rh1(OH)adjacent species,which is not found on the CeO2(100)crystal surface at room temperature.Furthermore,during CO oxidation,the OH group far from Rh single atom on the 0.5Rh1/c-CeO2 disappears and forms Rh1(OH)adjacent species when the temperature is above 150 ℃.The formation of Rh1(OH)adjacentCO intermediate in the reaction is pivotal for the excellent catalytic activity,which explains the difference in the catalytic activity of Rh single atoms on two different CeO2 planes.The formed Rh1(OH)adjacent-O-Ce structure exhibits good stability in the reducing atmosphere,maintaining the Rh atomic dispersion after CO oxidation even when pre-reduced at high temperature of 500 ℃.Density functional theory(DFT)calculations validate the unique activity and reaction path of the intermediate Rh1(OH)adjacentCO species formed.This work demonstrates that the proximity between metal single atom and hydroxyl can determine the formation of active intermediates to affect the catalytic performances in catalysis.
查看更多>>摘要：Promoting the oxygen reduction reaction(ORR)is critical for commercialization of intermediate-temperature solid oxide fuel cells(IT-SOFCs),where Sr2Fe1.5Mo0.5O6-δ(SFM)is a promising cathode by working as a mixed ionic and electronic conductor.In this work,doping of In3+greatly increases the oxygen vacancy concentration and the content of adsorbed oxygen species in Sr2Fe1.5Mo0.5-xInxO6-δ(SFMInx),and thus effectively promotes the ORR performance.As a typical example,SFMIn0.1 reduces the polarization resistance(Rp)from 0.089 to 0.046 Ω·cm2 at 800 ℃,which is superior to those doped with other metal elements.In addition,SFMIn0.1 increases the peak power density from 0.92 to 1.47 W-cm-2 at 800 ℃ with humidified H2 as the fuel,indicating that In3+doping at the Mo site can effectively improve the performance of SOFC cathode material.
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