Metal-nitrogen-carbon materials(M-N-C) are non-noble-metal-based alternatives to platinum-based catalysts and have attracted tremendous attention due to their low-cost,high abundance,and efficient catalytic performanc...Metal-nitrogen-carbon materials(M-N-C) are non-noble-metal-based alternatives to platinum-based catalysts and have attracted tremendous attention due to their low-cost,high abundance,and efficient catalytic performance towards the oxygen reduction reaction(ORR).Among them,Fe-based materials show remarkable ORR activity,but they are limited by low selectivity and low stability.To address these issues,herein,we have synthesized FeCu-based M-N-C catalysts,inspired by the bimetal center of cytochrome c oxidase(CcO).In acidic media,the selectivity was notably improved compared with Febased materials,with peroxide yields less than 1.2%(<1/3 of the hydrogen peroxide yields of Fe-N-C catalysts).In addition to Cu-N-C catalysts which can catalytically reduce hydrogen peroxide,the reduction current of hydrogen peroxide using FeCu-N-C-20 exceeded that of Fe-N-C by about 6% when the potential was greater than 0.4 V.Furthermore,FeCu-based M-N-C catalysts suffered from only a15 mV attenuation in their half-wave potentials after 10,000 cycles of accelerated degradation tests(ADT),while there was a 30 mV negative shift for Fe-N-C.Therefore,we propose that the H_(2)O_(2) released from Fe-Nx sites or N-doped carbon sites would be reduced by adjacent Cu-Nx sites,re sulting in low H_(2)O_(2) yields and high stability.展开更多
In this paper,a Slotted Stepped-Impedance Resonator (SSIR) is proposed.Due to the slots in the low-impedance section of the conventional SIR,the new resonator has a lower fundamental resonance f0 and can provide a pot...In this paper,a Slotted Stepped-Impedance Resonator (SSIR) is proposed.Due to the slots in the low-impedance section of the conventional SIR,the new resonator has a lower fundamental resonance f0 and can provide a potential finite transmission zero fz close to f0.Based on the proposed SSIR,a fourth-order Chebychev BandPass Filter (BPF) is designed at f0=1 GHz.The measured results show that a better than-65 dB rejection is achieved on both the lower and the upper stopband.Moreover,the new filter has a wide-30 dB rejection upper stopband from 1.13f0 to 6.52f0.The fabricated filter exhibits a size of The new filter has a planar topology and is easily integrated with modern portable communication systems.展开更多
Although defect engineering has been widely used to boost catalytic CO_(2) photoreduction,the piezoelectric polarized properties induced by structure changes through introducing defects are always ignored.Here we repo...Although defect engineering has been widely used to boost catalytic CO_(2) photoreduction,the piezoelectric polarized properties induced by structure changes through introducing defects are always ignored.Here we report a new kind of bismuth oxybromide(BiOBr,BOB)with piezoelectric property regulated by oxygen vacancies(OVs).Compared with pure BOB,BOB with OVs(BOB-OV)could enhance photocatalytic CO_(2) reduction efficiency under the ultrasonic force,achieving durable CO_(2) reduction process to superior production rates of CO(54.4μmol g^(-1) h^(-1))with a high selectivity(92%).Moderate OVs concentration changed the degree of Bi-Br stretching in the BOB-OV to produce strong dipole moments,which endowed BOB-OV with strong spontaneous piezoelectric polarization ability under external force.Ultrasonic piezoelectric effects were innovatively integrated into the photocatalytic reaction,which not only provided an alternating force field to modulate the spontaneous polarization of BOB-OV,thereby maintaining efficient photogenerated charge separation,but also lowered the reaction energy barrier of CO_(2) by high stress,ultimately improving CO product selectivity.This study is the first to leverage OVs-induced piezoelectric polarization effects to enhance the performance and product selectivity of photocatalytic CO_(2) reduction,providing new directions and insights for defect engineering to contribute to photocatalysis.展开更多
Photocatalytic reduction of CO_(2)into high-value C_(2)H_(4)offers a promising pathway toward carbon neutrality.Due to the continuous 12-electron-proton coupled reactions and the mutual repulsion of reaction intermedi...Photocatalytic reduction of CO_(2)into high-value C_(2)H_(4)offers a promising pathway toward carbon neutrality.Due to the continuous 12-electron-proton coupled reactions and the mutual repulsion of reaction intermediates,achieving highly selective photocatalytic conversion of CO_(2)to C_(2)H_(4)remains challenging.This work synthesized a CuInS_(2)/CuS heterojunction photocatalyst mediated by a sulfur electron bridge via a one-step solvothermal method,achieving a high selectivity for C_(2)H_(4)conversion(98.22%).The sulfur electron bridge minimized the contact energy barrier between CuInS_(2)and CuS to enhance photogenerated carrier separation efficiency,while the asymmetric active sites in CuInS_(2)effectively reduced mutual repulsion of reaction intermediates.This work develops a hybrid catalytic system enabling synergistic regulation of reaction kinetics and thermodynamics,offering an innovative strategy for highly selective photocatalytic CO₂-to-C_(2)H_(4)production.展开更多
Ammonia detection possesses great potential in atmosphere environmental protection,agriculture,industry,and rapid medical diagnosis.However,it still remains a great challenge to balance the sensitivity,selectivity,wor...Ammonia detection possesses great potential in atmosphere environmental protection,agriculture,industry,and rapid medical diagnosis.However,it still remains a great challenge to balance the sensitivity,selectivity,working temperature,and response/recovery speed.In this work,Berlin green(BG)framework is demonstrated as a highly promising sensing material for ammonia detection by both density functional theory simulation and experimental gas sensing investigation.Vacancy in BG framework offers abundant active sites for ammonia absorption,and the absorbed ammonia transfers sufficient electron to BG,arousing remarkable enhancement of resistance.Pristine BG framework shows remarkable response to ammonia at 50–110°C with the highest response at 80°C,which is jointly influenced by ammonia’s absorption onto BG surface and insertion into BG lattice.The sensing performance of BG can hardly be achieved at room temperature due to its high resistance.Introduction of conductive Ti3CN MXene overcomes the high resistance of pure BG framework,and the simply prepared BG/Ti3CN mixture shows high selectivity to ammonia at room temperature with satisfying response/recovery speed.展开更多
We demonstrate two distinct emerging terahertz （THz） biomedical imaging techniques.One is based on the use of a new single frequency THz quantum cascade laser and the other is based on broadband THz time domain spec...We demonstrate two distinct emerging terahertz （THz） biomedical imaging techniques.One is based on the use of a new single frequency THz quantum cascade laser and the other is based on broadband THz time domain spectrocopy.The first method is employed to derive a metastasis lung tissue imaging at 3.7 THz with clear contrast between cancerous and healthy areas.The second approach is used to study an osseous tissue under several imaging modalities and achieve full THz spectroscopic imaging based on the frequency domain or on a fixed THz propagation time-delay.Sufficient contrast is achieved which facilitated the identification of regions with different cellular types and density compositions.展开更多
Anion-selective electrodes based on dissociated ion-exchangers such as lipophilicquaternary ammonium or phosphonium species always display classical Hofmeister be-havior in the following order: ClO<sub>4</sub...Anion-selective electrodes based on dissociated ion-exchangers such as lipophilicquaternary ammonium or phosphonium species always display classical Hofmeister be-havior in the following order: ClO<sub>4</sub><sup>-</sup>】SCN<sup>-</sup>】I<sup>-</sup>】Br<sup>-</sup>】NO<sub>2</sub><sup>-</sup>】Cl<sup>-</sup>】SO<sub>4</sub><sup>2-</sup>.A new sol-vent polymeric membrane electrode based on Schiff base complexes of Co（Ⅱ）[Co（Ⅱ）S]and showing excellent selectivity toward iodide ion is for the first time prepared inour work. The resulting electrodes exhibit fairly low detection limits andpotentiometric anion-selectivity sequences deviated from the Hofmeister pattern.Bis（salicylaldehyde） ethylenediiminecobalt（Ⅱ） [Co（Ⅱ）（salen）], bis（salicylaldehyde）-phenyldiiminecobalt（Ⅱ） [Co（Ⅱ）（salophen）],展开更多
The electrochemical reduction of CO_(2)(eCO_(2)R)under ambient conditions is crucial for reducing carbon emissions and achieving carbon neutrality.Despite progress with alkaline and neutral electrolytes,their efficien...The electrochemical reduction of CO_(2)(eCO_(2)R)under ambient conditions is crucial for reducing carbon emissions and achieving carbon neutrality.Despite progress with alkaline and neutral electrolytes,their efficiency is limited by(bi)carbonates formation.Acidic media have emerged as a solution,addressing the(bi)carbonates challenge but introducing the issue of the hydrogen evolu-tion reaction(HER),which reduces CO_(2) conversion efficiency in acidic environments.This review focuses on enhancing the selectivity of acidic CO_(2) electrolysis.It commences with an overview of the latest advancements in acidic CO_(2) electrolysis,focusing on product selectivity and electrocatalytic activity enhancements.It then delves into the critical factors shaping selectivity in acidic CO_(2) electrolysis,with a special emphasis on the influence of cations and catalyst design.Finally,the research challenges and personal perspectives of acidic CO_(2) electrolysis are suggested.展开更多
Photoelectrochemistry provides an important application in the production of high-value-added chemicals.However,photoelectrochemical organic transformation with high product selectivity remains a challenge.Until now,v...Photoelectrochemistry provides an important application in the production of high-value-added chemicals.However,photoelectrochemical organic transformation with high product selectivity remains a challenge.Until now,various technologies have been developed to promote the selectivity of photoelectrochemical high-value-added chemical production.Herein,a novel ion-shielding heterogeneous photoelectrocatalysis strategy for the production of trifluoromethyl group(CF3)-containing compounds with high selectivity is described.展开更多
Electrocatalytic conversion presents a promising alternative to conventional industrial catalysis.While aqueous-phase electrocatalysis has achieved notable advancements,oil-water immiscible systems remain challenging ...Electrocatalytic conversion presents a promising alternative to conventional industrial catalysis.While aqueous-phase electrocatalysis has achieved notable advancements,oil-water immiscible systems remain challenging due to restricted reaction flux at multiphase interfaces.To address the limitation,we engineered a biphasic reaction system featuring a tailored oil-water catalytic interface in cyclohexene oxidation reaction(COR).The system employed a catalyst-loaded porous electrode as an active phase domain,enabling spatial separation of cyclohexene(organic phase)and electrolyte(aqueous phase).The tailored oil-water interface enhanced the interfacial mass transfer of substrate-catalysts and facilitated the spontaneous migration of 2-cyclohexen-1-ol into the aqueous phase,thereby streamlining product separation.Notably,polyaniline(PANI)modification on Co_(3)O_(4)enhanced surface lipophilicity,promoting cyclohexene adsorption and accelerating the COR catalytic kinetics(Co^(3+)-O+cyclohexene-H+e-→Co^(2+)-OH+2-cyclohexen-1-ol).The synergistic effects of optimized interfacial engineering and catalyst functionalization achieved exceptional performance:a current density of 45 mA·cm^(-2)at 1.6 V vs.reversible hydrogen electrode(V_(RHE)),coupled with 96.2%selectivity and 82.9%Faradaic efficiency.This work establishes an innovative paradigm for electrocatalytic conversions in oil-water immiscible systems through rational interface design and catalyst surface modulation.展开更多
Conversion of methane into liquid alcohol such as ethanol at low temperature in a straight,selective and low energy consumption process remains a topic of intense scientific research but a great challenge.In this work...Conversion of methane into liquid alcohol such as ethanol at low temperature in a straight,selective and low energy consumption process remains a topic of intense scientific research but a great challenge.In this work,CuFe_(2)O_(4)/CNT composite is successfully synthesized via a facile co-reduction method and used as catalysts to selectively oxidize methane.At a low temperature of 150℃,methane is directly converted to ethanol in a single process on the as-prepared CuFe_(2)O_(4)/CNT composite with high selectivity.A mechanism is also proposed for the significant methane selective oxidation performance of the CuFe_(2)O_(4)/CNT composite catalysts.展开更多
The conversion of CO_(2)into value-added chemicals coupled with the storage of intermittent renewable electricity is attractive.CuO nanosheets with an average size and thickness of~30 and~20 nm have been developed,whi...The conversion of CO_(2)into value-added chemicals coupled with the storage of intermittent renewable electricity is attractive.CuO nanosheets with an average size and thickness of~30 and~20 nm have been developed,which are in situ reduced into Cu nanosheets during electrochemical CO_(2)reduction reaction(ECO_(2)RR).The derived Cu nanosheets demonstrate much higher selectivity for C2H4production than commercial CuO derived Cu powder,with an optimum Faradaic efficiency of 56.2%and a partial current density of C_(2)H_(4)as large as 171.0 mA cm^(-2)in a gas diffusion flow cell.The operando attenuated total reflectance-Fourier transform infrared spectra measurements and density functional theory simulations illustrate that the high activity and selectivity of Cu nanosheets originate from the edge sites on Cu nanosheets with a coordinate number around 5(4–6),which facilitates the formation of^(*)CHO rather than^(*)COH intermediate,meanwhile boosting the C-C coupling reaction of^(*)CO and^(*)CHO intermediates,which are the critical steps for C_(2)H_(4)formation.展开更多
Although many plasmonic nanosenosrs have been established for the detection of mercury(Ⅱ)(Hg^(2+)),few of them is feasible for analyzing natural samples with very complex matrices because of insufficient method selec...Although many plasmonic nanosenosrs have been established for the detection of mercury(Ⅱ)(Hg^(2+)),few of them is feasible for analyzing natural samples with very complex matrices because of insufficient method selectivity.To address this challenge,we propose an epitaxial and lattice-mismatch approach to the synthesis of a unique Au/Ag_(2)S dimeric nanostructure,which consists of an Au segment with excellent plasmonic characteristics,and a highly stable Ag_(2)S portion with minimum solubility product (K_(sp)(Ag_(2)S)=6.3×10^(-50)).The detection relies on the chemical conversion of Ag_(2)S to HgS when reacting with Hg^(2+),resulting in a red shift in the absorption band of the connecting Au NPs.The concurrent color changes of the solution from gray purple to dark green and finally to navy correlate well with Hg^(2+)concentration,thus enables UV-vis quantitation and a naked-eye readout of the Hg^(2+)concentration.This method exhibits superior selectivity towards Hg^(2+) over other interfering ions tested because Hg^(2+) is the only ion that can react with Ag_(2)S to form HgS with even smaller solubility product (K_(sp)(HgS)=4×10^(-53)).The detection limit of this method is 1.21μmol/L,calculated by the signal-to-noise of 3.The practicability of the method was verified by analyzing the Hg^(2+)in sewage water samples without sample pretreatment with satisfactory recoveries (93.1%-102.8%) and relative standard deviations (1.38%-2.89%).We believe this method holds great potential for on-the-spot detection of Hg^(2+) in environmental water samples with complex matrices.展开更多
Fast development of nuclear power plants requires sustainable support of uranium for nuclear fuel.Uranium is the most critical radionuclide to prepare nuclear fuel.However,the extraction of low concentration of uraniu...Fast development of nuclear power plants requires sustainable support of uranium for nuclear fuel.Uranium is the most critical radionuclide to prepare nuclear fuel.However,the extraction of low concentration of uranium in uranium ore or complex systems needs highly efficient selective binding of uranium in the presence of other competing metal ions.The excellent oxidative capacity of excited*UO_(2)^(2+)active species makes uranyl-based materials high photocatalytic performance in phototransformation of organic chemicals into high valuable products under visible light irradiation.In this mini review,the selective preconcentration of uranium through photocatalytic and electrocatalytic strategies was mainly described.The application of uranyl-based materials in photocatalytic conversion and degradation of organic pollutants was summarized.This review reports the utilization of uranium from its first step(i.e.,extraction of uranium for nuclear fuel supply)to its last additional application(i.e.,uranyl-based materials as photocatalysts in transformation and conversion of organic pollutants for environmental pollution treatment)from the viewpoint of“turning uranium wastes into treasure,from waste recycling to reutilization.”In the end of this review,the challenges and perspectives of uranium separation and catalytic properties were described.展开更多
The membrane,one of the key components of flow batteries,ideally has high selectivity,conductivity,and stability.However,porous membranes prepared by conventional non-solvent-induced phase separation(NIPS)commonly suf...The membrane,one of the key components of flow batteries,ideally has high selectivity,conductivity,and stability.However,porous membranes prepared by conventional non-solvent-induced phase separation(NIPS)commonly suffer from low selectivity and poor mechanical stability.Here,we used rigid naphthalene-containing polybenzimidazole(NPBI)to prepare a porous membrane with unique egg-shaped pores by adjusting solvent/non-solvent exchange in NIPS.The dense pores with a size of 3.6Åarranged dispersedly between egg-shaped pores.The rigid NPBI and 3.6-Åsmall pores enabled the membrane high mechanical strength.The thickness was thus decreased to 1.4μm,which exhibited an ultrahigh tensile strength of 463.54 MPa.The dense pores were also smaller than hydrated vanadium ions,achieving a low permeability of 2.28×10^(-7)cm^(2)/h,indicating high selectivity.This is the first time to prepare such a highly selective and mechanically stable ultrathin porous membrane by NIPS.Importantly,the ion-transport pathways in the 1.4μm membrane were shortened,decreasing the area resistance to as low as 0.015Ωcm 2.Demonstrated in a vanadium flow battery,its coulombic efficiency was 98.57%and energy efficiency reached 81.72%at 200 mA/cm 2.This study proposes an effective strategy to prepare highperformance ultrathin porous membranes for flow batteries.展开更多
Alkane isomers(mainly C5-C7 alkanes),produced via catalytic isomerization reactions during oil refinement,are important raw chemicals in the petrochemical industry[1].They are used in a broad spectrum of chemical proc...Alkane isomers(mainly C5-C7 alkanes),produced via catalytic isomerization reactions during oil refinement,are important raw chemicals in the petrochemical industry[1].They are used in a broad spectrum of chemical processes,depending on their branching.Specifically,normal alkanes and monobranched isomers are premium ethylene feed,and dibranched isomers are desired components for high-rating gasolines[2].Consequently,the isomers must be separated before further use.展开更多
People living on the high plateaus of the world have long fascinated biological anthropologists and geneticists because they live in ＂thin air＂ and epitomize an extreme of human biological adaptation.
A highly selective nitric oxide（NO） sensor is fabricated and applied to devise an enhanced flow injection analysis（FIA） system for S-nitrosothiols（RSNOs） measurement in biological samples.The NO sensor is prepar...A highly selective nitric oxide（NO） sensor is fabricated and applied to devise an enhanced flow injection analysis（FIA） system for S-nitrosothiols（RSNOs） measurement in biological samples.The NO sensor is prepared using a polytetrafluoroethylene（PTFE） gas-permeable membrane loaded with Teflon AF？ solution,a copolymer of tetrafluoroethylene and 2,2-bis（trifluoroethylene）-4,5-difluoro -l,3-dioxole,to improve selectivity.This method is much simpler and possesses good performance over a wide range of RSNOs concentrations.Standard deviation for three parallel measurements of blood plasma is 4.0%.The use of the gas sensing configuration as the detector enhances selectivity of the FIA measurement vs.using less selective electrochemical detectors that do not use PTFE/Teflon type outer membranes.展开更多
The most challenging goal of C1 chemistry is the control of C–C coupling to produce chemicals or fuels from C1 feedstocks,in particular syngas（H2/CO）,which can be derived from various carbon resources such as coal,...The most challenging goal of C1 chemistry is the control of C–C coupling to produce chemicals or fuels from C1 feedstocks,in particular syngas（H2/CO）,which can be derived from various carbon resources such as coal,natural gas or shale gas,and biomass.展开更多
A new tetraphenylethylene-cyclodextrin (TPE-CD) conjugate with a linkage composed of long triethylene glycol chain and triazole ring on the CD rim has been designed and synthesized. The TPE-CD conjugate exists in a st...A new tetraphenylethylene-cyclodextrin (TPE-CD) conjugate with a linkage composed of long triethylene glycol chain and triazole ring on the CD rim has been designed and synthesized. The TPE-CD conjugate exists in a stretched form in DMSO and enhances its fluorescence after addition of a small amount of water due to aggregation-induced emission (AIE) effect. However, in the presence of a large amount of water, the TPE unit will enter the cyclodextrin cavity to form a folded self-inclusion compound. In the self-inclusion compound, not only nitrogen-containing pseudo-crown ether is formed but also arouses photo-induced electron transfer (PET) process from nitrogen atoms of triazole ring to TPE unit and quenches the fluorescence although more aggregation occurs in more water. This is the first finding that TPE-macrocycle conjugate can form pseudo-crown ether and has both the AIE phenomenon and the PET effect. Interestingly, only mercury ion arouses the fluorescence recover of the self-inclusion compound by entering the pseudo-crown ether cavity and blocking the PET process by binding to the nitrogen atoms, while other tested metal ions almost have no effect on the fluorescence. Therefore, the TPE-CD conjugate can be used for the highly selective fluorescence "Turn-On" detection of Hg^(2+).展开更多
基金the National Science and Technology Major Project(No.2017YFB0102900)the National Natural Science Foundation of China(Nos.21633008,21433003)+1 种基金the Jilin Province Science and Technology Development Program(No.20170203003SF)the Hundred Talents Program of the Chinese Academy of Sciences for financial support。
文摘Metal-nitrogen-carbon materials(M-N-C) are non-noble-metal-based alternatives to platinum-based catalysts and have attracted tremendous attention due to their low-cost,high abundance,and efficient catalytic performance towards the oxygen reduction reaction(ORR).Among them,Fe-based materials show remarkable ORR activity,but they are limited by low selectivity and low stability.To address these issues,herein,we have synthesized FeCu-based M-N-C catalysts,inspired by the bimetal center of cytochrome c oxidase(CcO).In acidic media,the selectivity was notably improved compared with Febased materials,with peroxide yields less than 1.2%(<1/3 of the hydrogen peroxide yields of Fe-N-C catalysts).In addition to Cu-N-C catalysts which can catalytically reduce hydrogen peroxide,the reduction current of hydrogen peroxide using FeCu-N-C-20 exceeded that of Fe-N-C by about 6% when the potential was greater than 0.4 V.Furthermore,FeCu-based M-N-C catalysts suffered from only a15 mV attenuation in their half-wave potentials after 10,000 cycles of accelerated degradation tests(ADT),while there was a 30 mV negative shift for Fe-N-C.Therefore,we propose that the H_(2)O_(2) released from Fe-Nx sites or N-doped carbon sites would be reduced by adjacent Cu-Nx sites,re sulting in low H_(2)O_(2) yields and high stability.
文摘In this paper,a Slotted Stepped-Impedance Resonator (SSIR) is proposed.Due to the slots in the low-impedance section of the conventional SIR,the new resonator has a lower fundamental resonance f0 and can provide a potential finite transmission zero fz close to f0.Based on the proposed SSIR,a fourth-order Chebychev BandPass Filter (BPF) is designed at f0=1 GHz.The measured results show that a better than-65 dB rejection is achieved on both the lower and the upper stopband.Moreover,the new filter has a wide-30 dB rejection upper stopband from 1.13f0 to 6.52f0.The fabricated filter exhibits a size of The new filter has a planar topology and is easily integrated with modern portable communication systems.
文摘Although defect engineering has been widely used to boost catalytic CO_(2) photoreduction,the piezoelectric polarized properties induced by structure changes through introducing defects are always ignored.Here we report a new kind of bismuth oxybromide(BiOBr,BOB)with piezoelectric property regulated by oxygen vacancies(OVs).Compared with pure BOB,BOB with OVs(BOB-OV)could enhance photocatalytic CO_(2) reduction efficiency under the ultrasonic force,achieving durable CO_(2) reduction process to superior production rates of CO(54.4μmol g^(-1) h^(-1))with a high selectivity(92%).Moderate OVs concentration changed the degree of Bi-Br stretching in the BOB-OV to produce strong dipole moments,which endowed BOB-OV with strong spontaneous piezoelectric polarization ability under external force.Ultrasonic piezoelectric effects were innovatively integrated into the photocatalytic reaction,which not only provided an alternating force field to modulate the spontaneous polarization of BOB-OV,thereby maintaining efficient photogenerated charge separation,but also lowered the reaction energy barrier of CO_(2) by high stress,ultimately improving CO product selectivity.This study is the first to leverage OVs-induced piezoelectric polarization effects to enhance the performance and product selectivity of photocatalytic CO_(2) reduction,providing new directions and insights for defect engineering to contribute to photocatalysis.
文摘Photocatalytic reduction of CO_(2)into high-value C_(2)H_(4)offers a promising pathway toward carbon neutrality.Due to the continuous 12-electron-proton coupled reactions and the mutual repulsion of reaction intermediates,achieving highly selective photocatalytic conversion of CO_(2)to C_(2)H_(4)remains challenging.This work synthesized a CuInS_(2)/CuS heterojunction photocatalyst mediated by a sulfur electron bridge via a one-step solvothermal method,achieving a high selectivity for C_(2)H_(4)conversion(98.22%).The sulfur electron bridge minimized the contact energy barrier between CuInS_(2)and CuS to enhance photogenerated carrier separation efficiency,while the asymmetric active sites in CuInS_(2)effectively reduced mutual repulsion of reaction intermediates.This work develops a hybrid catalytic system enabling synergistic regulation of reaction kinetics and thermodynamics,offering an innovative strategy for highly selective photocatalytic CO₂-to-C_(2)H_(4)production.
基金The research was supported by the National Natural Science Foundation of China(Grant Nos.61435010,61675135,and 62005177)the National Natural Science Foundation for Young Scientists of China(Grant No.61905161)the Science and Technology Innovation Commission of Shenzhen(JCYJ20190808142415003).Authors also acknowledge the support from Instrumental Analysis Center of Shenzhen University(Xili Campus).
文摘Ammonia detection possesses great potential in atmosphere environmental protection,agriculture,industry,and rapid medical diagnosis.However,it still remains a great challenge to balance the sensitivity,selectivity,working temperature,and response/recovery speed.In this work,Berlin green(BG)framework is demonstrated as a highly promising sensing material for ammonia detection by both density functional theory simulation and experimental gas sensing investigation.Vacancy in BG framework offers abundant active sites for ammonia absorption,and the absorbed ammonia transfers sufficient electron to BG,arousing remarkable enhancement of resistance.Pristine BG framework shows remarkable response to ammonia at 50–110°C with the highest response at 80°C,which is jointly influenced by ammonia’s absorption onto BG surface and insertion into BG lattice.The sensing performance of BG can hardly be achieved at room temperature due to its high resistance.Introduction of conductive Ti3CN MXene overcomes the high resistance of pure BG framework,and the simply prepared BG/Ti3CN mixture shows high selectivity to ammonia at room temperature with satisfying response/recovery speed.
基金supported by the National Science Foundation,USA
文摘We demonstrate two distinct emerging terahertz （THz） biomedical imaging techniques.One is based on the use of a new single frequency THz quantum cascade laser and the other is based on broadband THz time domain spectrocopy.The first method is employed to derive a metastasis lung tissue imaging at 3.7 THz with clear contrast between cancerous and healthy areas.The second approach is used to study an osseous tissue under several imaging modalities and achieve full THz spectroscopic imaging based on the frequency domain or on a fixed THz propagation time-delay.Sufficient contrast is achieved which facilitated the identification of regions with different cellular types and density compositions.
基金National Natural Science Foundation of ChinaElectroanalytical Chemistry Laboratory, Changchun Institute of Applied Chemistry, Academia Sinica.
文摘Anion-selective electrodes based on dissociated ion-exchangers such as lipophilicquaternary ammonium or phosphonium species always display classical Hofmeister be-havior in the following order: ClO<sub>4</sub><sup>-</sup>】SCN<sup>-</sup>】I<sup>-</sup>】Br<sup>-</sup>】NO<sub>2</sub><sup>-</sup>】Cl<sup>-</sup>】SO<sub>4</sub><sup>2-</sup>.A new sol-vent polymeric membrane electrode based on Schiff base complexes of Co（Ⅱ）[Co（Ⅱ）S]and showing excellent selectivity toward iodide ion is for the first time prepared inour work. The resulting electrodes exhibit fairly low detection limits andpotentiometric anion-selectivity sequences deviated from the Hofmeister pattern.Bis（salicylaldehyde） ethylenediiminecobalt（Ⅱ） [Co（Ⅱ）（salen）], bis（salicylaldehyde）-phenyldiiminecobalt（Ⅱ） [Co（Ⅱ）（salophen）],
文摘The electrochemical reduction of CO_(2)(eCO_(2)R)under ambient conditions is crucial for reducing carbon emissions and achieving carbon neutrality.Despite progress with alkaline and neutral electrolytes,their efficiency is limited by(bi)carbonates formation.Acidic media have emerged as a solution,addressing the(bi)carbonates challenge but introducing the issue of the hydrogen evolu-tion reaction(HER),which reduces CO_(2) conversion efficiency in acidic environments.This review focuses on enhancing the selectivity of acidic CO_(2) electrolysis.It commences with an overview of the latest advancements in acidic CO_(2) electrolysis,focusing on product selectivity and electrocatalytic activity enhancements.It then delves into the critical factors shaping selectivity in acidic CO_(2) electrolysis,with a special emphasis on the influence of cations and catalyst design.Finally,the research challenges and personal perspectives of acidic CO_(2) electrolysis are suggested.
基金supported by the National Natural Science Foundation of China(nos.51902297,12175200,and 22109120)the Science Development Foundation of Hubei University of Science and Technology(no.2022T03)the State Key Laboratory of New Textile Materials and Advanced Processing Technologies(no.FZ2023005).
文摘Photoelectrochemistry provides an important application in the production of high-value-added chemicals.However,photoelectrochemical organic transformation with high product selectivity remains a challenge.Until now,various technologies have been developed to promote the selectivity of photoelectrochemical high-value-added chemical production.Herein,a novel ion-shielding heterogeneous photoelectrocatalysis strategy for the production of trifluoromethyl group(CF3)-containing compounds with high selectivity is described.
基金supported by the National Natural Science Foundation of China(No.22278380)China Postdoctoral Science Foundation(Nos.2024M762994 and GZC20232392)supported by the project of Yunnan Key Laboratory of Electromagnetic Materials and Devices,Yunnan University(No.ZZ2024009).
文摘Electrocatalytic conversion presents a promising alternative to conventional industrial catalysis.While aqueous-phase electrocatalysis has achieved notable advancements,oil-water immiscible systems remain challenging due to restricted reaction flux at multiphase interfaces.To address the limitation,we engineered a biphasic reaction system featuring a tailored oil-water catalytic interface in cyclohexene oxidation reaction(COR).The system employed a catalyst-loaded porous electrode as an active phase domain,enabling spatial separation of cyclohexene(organic phase)and electrolyte(aqueous phase).The tailored oil-water interface enhanced the interfacial mass transfer of substrate-catalysts and facilitated the spontaneous migration of 2-cyclohexen-1-ol into the aqueous phase,thereby streamlining product separation.Notably,polyaniline(PANI)modification on Co_(3)O_(4)enhanced surface lipophilicity,promoting cyclohexene adsorption and accelerating the COR catalytic kinetics(Co^(3+)-O+cyclohexene-H+e-→Co^(2+)-OH+2-cyclohexen-1-ol).The synergistic effects of optimized interfacial engineering and catalyst functionalization achieved exceptional performance:a current density of 45 mA·cm^(-2)at 1.6 V vs.reversible hydrogen electrode(V_(RHE)),coupled with 96.2%selectivity and 82.9%Faradaic efficiency.This work establishes an innovative paradigm for electrocatalytic conversions in oil-water immiscible systems through rational interface design and catalyst surface modulation.
基金financially supported by the National Natural Science Foundation of China(No.21975163)Bureau of Industry and Information Technology of Shenzhen(No.201901171518)+1 种基金Shenzhen Science and Technology Program(No.KQTD20190929173914967)the support provided by Instrumental Analysis Center of Shenzhen University(Xili Campus)。
文摘Conversion of methane into liquid alcohol such as ethanol at low temperature in a straight,selective and low energy consumption process remains a topic of intense scientific research but a great challenge.In this work,CuFe_(2)O_(4)/CNT composite is successfully synthesized via a facile co-reduction method and used as catalysts to selectively oxidize methane.At a low temperature of 150℃,methane is directly converted to ethanol in a single process on the as-prepared CuFe_(2)O_(4)/CNT composite with high selectivity.A mechanism is also proposed for the significant methane selective oxidation performance of the CuFe_(2)O_(4)/CNT composite catalysts.
基金funded by the National Key Research and Development Program of China(2017YFA0700103,2018YFA0704502)the National Natural Science Foundation of China(21703248)staffs in BL11B beamline in Shanghai Synchrotron Radiation Facility(SSRF)for their technical assistance(2020-SSRF-PT-012223 and 2021-SSRF-PT-015319)。
文摘The conversion of CO_(2)into value-added chemicals coupled with the storage of intermittent renewable electricity is attractive.CuO nanosheets with an average size and thickness of~30 and~20 nm have been developed,which are in situ reduced into Cu nanosheets during electrochemical CO_(2)reduction reaction(ECO_(2)RR).The derived Cu nanosheets demonstrate much higher selectivity for C2H4production than commercial CuO derived Cu powder,with an optimum Faradaic efficiency of 56.2%and a partial current density of C_(2)H_(4)as large as 171.0 mA cm^(-2)in a gas diffusion flow cell.The operando attenuated total reflectance-Fourier transform infrared spectra measurements and density functional theory simulations illustrate that the high activity and selectivity of Cu nanosheets originate from the edge sites on Cu nanosheets with a coordinate number around 5(4–6),which facilitates the formation of^(*)CHO rather than^(*)COH intermediate,meanwhile boosting the C-C coupling reaction of^(*)CO and^(*)CHO intermediates,which are the critical steps for C_(2)H_(4)formation.
基金supported by the National Natural Science Foundation of China(No.21876206)the Key Fundamental Project of Shandong Natural Science Foundation(No.ZR2020ZD13)+1 种基金the Science and Technology Projects of Qingdao(No.21–1–4-sf-7-nsh)the Youth Innovation and Technology project of Universities in Shandong Province(No.2020KJC007)。
文摘Although many plasmonic nanosenosrs have been established for the detection of mercury(Ⅱ)(Hg^(2+)),few of them is feasible for analyzing natural samples with very complex matrices because of insufficient method selectivity.To address this challenge,we propose an epitaxial and lattice-mismatch approach to the synthesis of a unique Au/Ag_(2)S dimeric nanostructure,which consists of an Au segment with excellent plasmonic characteristics,and a highly stable Ag_(2)S portion with minimum solubility product (K_(sp)(Ag_(2)S)=6.3×10^(-50)).The detection relies on the chemical conversion of Ag_(2)S to HgS when reacting with Hg^(2+),resulting in a red shift in the absorption band of the connecting Au NPs.The concurrent color changes of the solution from gray purple to dark green and finally to navy correlate well with Hg^(2+)concentration,thus enables UV-vis quantitation and a naked-eye readout of the Hg^(2+)concentration.This method exhibits superior selectivity towards Hg^(2+) over other interfering ions tested because Hg^(2+) is the only ion that can react with Ag_(2)S to form HgS with even smaller solubility product (K_(sp)(HgS)=4×10^(-53)).The detection limit of this method is 1.21μmol/L,calculated by the signal-to-noise of 3.The practicability of the method was verified by analyzing the Hg^(2+)in sewage water samples without sample pretreatment with satisfactory recoveries (93.1%-102.8%) and relative standard deviations (1.38%-2.89%).We believe this method holds great potential for on-the-spot detection of Hg^(2+) in environmental water samples with complex matrices.
基金support from the National Natural Science Foundation of China(Nos.U24B20195,U23A20105,U2341289,22341602,22327807)was acknowledged.
文摘Fast development of nuclear power plants requires sustainable support of uranium for nuclear fuel.Uranium is the most critical radionuclide to prepare nuclear fuel.However,the extraction of low concentration of uranium in uranium ore or complex systems needs highly efficient selective binding of uranium in the presence of other competing metal ions.The excellent oxidative capacity of excited*UO_(2)^(2+)active species makes uranyl-based materials high photocatalytic performance in phototransformation of organic chemicals into high valuable products under visible light irradiation.In this mini review,the selective preconcentration of uranium through photocatalytic and electrocatalytic strategies was mainly described.The application of uranyl-based materials in photocatalytic conversion and degradation of organic pollutants was summarized.This review reports the utilization of uranium from its first step(i.e.,extraction of uranium for nuclear fuel supply)to its last additional application(i.e.,uranyl-based materials as photocatalysts in transformation and conversion of organic pollutants for environmental pollution treatment)from the viewpoint of“turning uranium wastes into treasure,from waste recycling to reutilization.”In the end of this review,the challenges and perspectives of uranium separation and catalytic properties were described.
基金supported by the National Key R&D Program of China(No.2022YFB3805302)the National Natural Science Foundation of China(No.22379141)+2 种基金CAS Strategic Leading Science&Technology Program(A)(No.XDA0400201)Dalian Science and Technology Star Program(No.2022RQ014)Youth Innovation Promotion Association CAS(No.2022184).
文摘The membrane,one of the key components of flow batteries,ideally has high selectivity,conductivity,and stability.However,porous membranes prepared by conventional non-solvent-induced phase separation(NIPS)commonly suffer from low selectivity and poor mechanical stability.Here,we used rigid naphthalene-containing polybenzimidazole(NPBI)to prepare a porous membrane with unique egg-shaped pores by adjusting solvent/non-solvent exchange in NIPS.The dense pores with a size of 3.6Åarranged dispersedly between egg-shaped pores.The rigid NPBI and 3.6-Åsmall pores enabled the membrane high mechanical strength.The thickness was thus decreased to 1.4μm,which exhibited an ultrahigh tensile strength of 463.54 MPa.The dense pores were also smaller than hydrated vanadium ions,achieving a low permeability of 2.28×10^(-7)cm^(2)/h,indicating high selectivity.This is the first time to prepare such a highly selective and mechanically stable ultrathin porous membrane by NIPS.Importantly,the ion-transport pathways in the 1.4μm membrane were shortened,decreasing the area resistance to as low as 0.015Ωcm 2.Demonstrated in a vanadium flow battery,its coulombic efficiency was 98.57%and energy efficiency reached 81.72%at 200 mA/cm 2.This study proposes an effective strategy to prepare highperformance ultrathin porous membranes for flow batteries.
基金supported by the Key Program of National Natural Science Foundation of China(22438001)the National Natural Science Foundation of China(22478251,52373212)+1 种基金the Shenzhen Science and Technology Program(KCXFZ20211020163818026)the Shenzhen Polytechnic University Research Fund(6024310024K)。
文摘Alkane isomers(mainly C5-C7 alkanes),produced via catalytic isomerization reactions during oil refinement,are important raw chemicals in the petrochemical industry[1].They are used in a broad spectrum of chemical processes,depending on their branching.Specifically,normal alkanes and monobranched isomers are premium ethylene feed,and dibranched isomers are desired components for high-rating gasolines[2].Consequently,the isomers must be separated before further use.
文摘People living on the high plateaus of the world have long fascinated biological anthropologists and geneticists because they live in ＂thin air＂ and epitomize an extreme of human biological adaptation.
基金the Project of Base for Introducing Talents of Discipline to Universities(111 project,NoB07012)National Scholarship Fund of the China Scholarship Council for supporting visiting students in foreign universities
文摘A highly selective nitric oxide（NO） sensor is fabricated and applied to devise an enhanced flow injection analysis（FIA） system for S-nitrosothiols（RSNOs） measurement in biological samples.The NO sensor is prepared using a polytetrafluoroethylene（PTFE） gas-permeable membrane loaded with Teflon AF？ solution,a copolymer of tetrafluoroethylene and 2,2-bis（trifluoroethylene）-4,5-difluoro -l,3-dioxole,to improve selectivity.This method is much simpler and possesses good performance over a wide range of RSNOs concentrations.Standard deviation for three parallel measurements of blood plasma is 4.0%.The use of the gas sensing configuration as the detector enhances selectivity of the FIA measurement vs.using less selective electrochemical detectors that do not use PTFE/Teflon type outer membranes.
文摘The most challenging goal of C1 chemistry is the control of C–C coupling to produce chemicals or fuels from C1 feedstocks,in particular syngas（H2/CO）,which can be derived from various carbon resources such as coal,natural gas or shale gas,and biomass.
基金National Natural Science Foundation of China(Nos. 91856125 and 21673089)HUST Graduate Innovation Fund for financial support。
文摘A new tetraphenylethylene-cyclodextrin (TPE-CD) conjugate with a linkage composed of long triethylene glycol chain and triazole ring on the CD rim has been designed and synthesized. The TPE-CD conjugate exists in a stretched form in DMSO and enhances its fluorescence after addition of a small amount of water due to aggregation-induced emission (AIE) effect. However, in the presence of a large amount of water, the TPE unit will enter the cyclodextrin cavity to form a folded self-inclusion compound. In the self-inclusion compound, not only nitrogen-containing pseudo-crown ether is formed but also arouses photo-induced electron transfer (PET) process from nitrogen atoms of triazole ring to TPE unit and quenches the fluorescence although more aggregation occurs in more water. This is the first finding that TPE-macrocycle conjugate can form pseudo-crown ether and has both the AIE phenomenon and the PET effect. Interestingly, only mercury ion arouses the fluorescence recover of the self-inclusion compound by entering the pseudo-crown ether cavity and blocking the PET process by binding to the nitrogen atoms, while other tested metal ions almost have no effect on the fluorescence. Therefore, the TPE-CD conjugate can be used for the highly selective fluorescence "Turn-On" detection of Hg^(2+).
