The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts c...The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.展开更多
Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are...Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are highly susceptible to framework charge,which plays a significant role in selective adsorption.Currently,ionic porous frameworks can be divided into two types.One of them is composed of a charged backbone and counter ions.The framework with zwitterionic channels is another type.It is composed of regular and alternating arrangements of cationic and anionic building units.Herein,we report a hydrogen-bonded ionic framework(HIF)of{(CN_(3)H_(6))_(2)[Ti(μ_(2)-O)(SO_(4))_(2)]}_nwith 1D channel exhibits unique adsorption selectivity for Ar against N_(2)and CO_(2).Density functional theory(DFT)results suggest that CO_(2)cannot be adsorbed by HIF at the experimental temperature due to a positive adsorption free energy.In addition,due to a relatively large diffusion barrier at 77 K,N_(2)molecules hardly diffuse in HIF channels,while Ar has a negligible diffusion barrier.The unique net positively-charged space in the channel is the key to the unusual phenomena,based on DFT simulations and structural analysis.The findings in this work proposes the new adsorption mechanism and provides unique perspective for special separation applications,such as isotope and noble gasses separations.展开更多
Improving the selectivity of resistive gas sensors and understanding the mechanism of gas sensors are quite significant for the design and application of gas sensors in practical application.In this work,a high select...Improving the selectivity of resistive gas sensors and understanding the mechanism of gas sensors are quite significant for the design and application of gas sensors in practical application.In this work,a high selective acetone sensor based on n-n homojunction by loading ZnO quantum dots(QDs)onto ZnO nanorod(ZnO QDs@ZnO nanorod)sensing material was fabricated.The microstructure and element analysis of ZnO QDs@ZnO nanorod were characterized by transmission electron microscope,X-ray photoelectron spectroscopy(XPS),and X-ray diffraction.The experimental results showed that the sensor possesses excellent acetone selectivity(selectivity coefficient S1/S2=8.76,where S1 represents the response value of the sensor to acetone and S2 represents the response value of the sensor to interfering gas at the same concentration).The prepared sensor has the low detection limit of acetone(10 ppb).The sensing mechanism of enhanced selectivity for acetone was explored by in-situ Raman test and XPS,in which the n-n homojunction-associated conversion of lattice oxygen to surface adsorbed oxygen is proposed.Theoretical calculation demonstrates the transformation from lattice oxygen to adsorbed oxygen and the enhanced ability of acetone adsorption.The improved selectivity and the deep investigation of the mechanism provide an effective way for the design of highly selective gas sensing materials.展开更多
Inspired by natural Ca^(2+)channels,we design and synthesize a type of artificial Ca^(2+)carriers using o-phenanthroline-oxadiazole-based foldamers.Through the incorporation of negative charges into cavity-containing ...Inspired by natural Ca^(2+)channels,we design and synthesize a type of artificial Ca^(2+)carriers using o-phenanthroline-oxadiazole-based foldamers.Through the incorporation of negative charges into cavity-containing foldamers,highly selective calcium ion transmembrane transport can be achieved,leading to the identification of two highly efficient Ca^(2+)carriers.Systematic investigation revealed a positive correlation between the number of negative charges on the foldamers and the foldamers‘cation-binding affinity.Furthermore,the size-selective effect,achieved through precise matching between the foldamer cavity dimensions and Ca^(2+)ion size,resulted in an unprecedented Ca^(2+)/Mg^(2+)selectivity ratio(S_(Ca/Mg)),reaching record S_(Ca/Mg) values greater than 100–the highest of all artificial Ca^(2+)carriers reported to date.Moreover,artificial Ca^(2+)carriers show high Ca^(2+)transport activity(EC_(50)=190 nM).This simple and modular approach enables tailored design of divalent cation transporters,thus providing promising applications for artificial divalent cation transporters in the fields of biochemistry and material chemistry.展开更多
BACKGROUND Autism spectrum disorder(ASD)is a neurodevelopmental disorder that manifests in the first years of life,with a complex pathogenesis influenced by biological,genetic and epigenetic factors.Many children with...BACKGROUND Autism spectrum disorder(ASD)is a neurodevelopmental disorder that manifests in the first years of life,with a complex pathogenesis influenced by biological,genetic and epigenetic factors.Many children with ASD display marked food selectivity,often restricting themselves to a narrow range of foods.The problems associated with feeding children with ASD can vary widely,from mild cases that pose no immediate health risks,to more severe situations with a risk of mal-nutrition or,conversely,overeating.This scoping review aims to provide an in-depth overview of the frequency,nature and factors related to food selectivity in children with autism.AIM To comprehensively review the literature on food selectivity in ASD.METHODS A systematic review of the literature was conducted using the PubMed,Web of Science and EBSCO databases,to identify articles published in English from 2014 until 2024.Studies on a sample diagnosed with ASD and food selectivity were included.The selected databases were chosen for their broad coverage of the scientific literature.These databases represent reliable sources of high-quality articles,ensuring a comprehensive and up-to-date search.RESULTS We evaluated 222 studies on food selectivity in autism,from which duplicates were removed and unrelated titles were filtered out.Finally,9 articles were included in the review.Five articles provide a general overview of the phenomenon,analysing its nature and factors.Two studies delve into sensory sensitivity,in particular the impact of food textures,tastes and smells.Finally,two studies focus on problem behaviour during mealtimes.CONCLUSION Children with ASD have greater food selectivity than the neurotypical population.The diet should contain a greater variety of fruit,vegetables,yoghurt,while reducing the consumption of rice and pasta.展开更多
Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we d...Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we demonstrate the improved low-temperature activity and N_(2)selectivity by regulating the redox and acidic properties of MnCe oxides supported on etched ZSM-5 supports.The etched ZSM-5 enables the highly dispersed state of MnCeOx species and strong interaction between Mn and Ce species,which promotes the reduction of CeO2,facilitates electron transfer from Mn to Ce,and generates more Mn^(4+)and Ce^(3+)species.The strong redox capacity contributes to forming the reactive nitrate species and-NH_(2)species from oxidative dehydrogenation of NH_(3).Moreover,the adsorbed NH_(3)and-NH_(2)species are the reactive intermediates that promote the formation of N_(2).This work demonstrates an effective strategy to enhance the low-temperature activity and N_(2)selectivity of SCR catalysts,contributing to the NO_(x)control for the low-temperature exhaust gas during the cold-start of diesel vehicles.展开更多
Aldehydes are valuable intermediates with widespread industrial applications,and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly.Electrochemical oxidatio...Aldehydes are valuable intermediates with widespread industrial applications,and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly.Electrochemical oxidation offers a more sustainable and milder alternative;however,it faces challenges such as aldehyde overoxidation and susceptibility to base-catalyzed Cannizzaro disproportionation.Electrochemical glycerol oxidation to glyceraldehyde is a representative example,which typically requires precious metal-based electrocatalysts but still suffers from low selectivity and activity.Here,we report a metal-free oxidation strategy mediated by 2,2,6,6-tetramethylpiperidine-1-oxyl.By systematically investigating the redox thermodynamics and kinetics of TEMPO across a broad pH range,we construct a Pourbaix diagram and elucidate the relative kinetics of each reaction step.These insights allow us to explain the anomalously high apparent Faradaic efficiency(~200%)observed under acidic conditions,and identify neutral media as the optimal environment for selective glyceraldehyde production.Under optimized conditions,our system achieves a glyceraldehyde Faradaic efficiency exceeding 93%and a partial current density of 23.3 mA cm^(-2)at 0.57 V—more than doubling the performance of the best reported precious metal-based systems.Furthermore,the versatility of this strategy extends to the selective oxidation of other primary alcohols to their corresponding aldehydes with near-unity selectivity.展开更多
Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but ful...Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but full of great challenge.Herein,a cationic In-captured Zr-porphyrin framework(1)with nanosized pores/cages was successfully constructed and showed high structure stability.Catalytic investigations revealed that 1 displayed highly multi-selective CTH of aldehydes and ketones containing both chemo-and size selectivity for the first time.The CTH of aldehydes and ketones exhibited remarkable reductive selectivity of 99%towards C=O bonds into CH–OH in the presence of-NO_(2),-CN and C=C groups.Through tuning the reaction conditions,1 also exhibited highly selective reduction of 97%for-CHO groups in the simultaneous presence of-CHO and-COCH3groups in intra-and intermolecular settings.Remarkably,reductive selectivity towards-CHO group remained prominent among five concurrent unsaturated groups mentioned above.Additionally,the definite pore size of 1 facilitated volume control of substrates,enabling size selectivity.1 as a heterogeneous catalyst was further confirmed by leaching tests,and maintained high activity even after being used for at least six cycles.Mechanistic studies have revealed that Zr6O8clusters served as the catalytic centers and the observed chemoselectivity mainly results from the synergistic effect of distinct metal sites within 1.The heightened selectivity towards-CHO over-COCH_(3)can be attributed to the easier realization of transfer hydrogenation processes for-CHO compared to-COCH_(3).展开更多
The increasing demand for electronics has led to a desire to recover rare earth elements(REEs) from nonconventional sources,including mining and liquid waste effluents.Biosorption could be a promising method for adsor...The increasing demand for electronics has led to a desire to recover rare earth elements(REEs) from nonconventional sources,including mining and liquid waste effluents.Biosorption could be a promising method for adsorbing REEs onto microalgae,but biomass immobilization and light delivery challenges remain.It was recently shown that REEs biosorb 160% more on algal biofilms than suspended biomass due to the extracellular polymeric substance(EPS) matrix that grows abundantly in biofilms.In this work,we present findings on biosorption selectivity for different REEs in sulfate solutions.The maximum adsorption capacities of Euglena mutabilis suspensions and biofilms were determined for a mixed REE sulfate solution at an equimolar initial concentration range of 0.1-1 mol/L of each REE ion.The highest adsorption capacities for the suspension are for Sm and Eu which are 57% and 46% higher,respectively,compared to the average REE adsorption capacity.The biofilms also preferentially adsorb Sm,Eu,Yb and Lu at 0.035,0.033,0.033,and 0.031 mmol/g,respectively.The impact of dissolved divalent ions of Ca,Mg,and Fe on REE adsorption was also assessed.When Ca and Mg are added in equimolar amounts to0.1-1 mmol/L solutions of equimolar La,Eu,and Yb sulfate,the amount of REEs adsorbed onto suspensions increases by 30% while when Fe is added,it decreases by 10%.No change is observed in biofilms except when Fe is added resulting in a reduction of the adsorption capacity by 40%.A possible explanation for the role of Fe is attributed to the formation of stronger bonds at the binding sites compared to Ca and Mg.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
Electrocatalytic reduction of nitrate to ammonia has been considered a promising and sustainable pathway for pollutant treatment and ammonia has significant potential as a clean energy.Therefore,the method has receive...Electrocatalytic reduction of nitrate to ammonia has been considered a promising and sustainable pathway for pollutant treatment and ammonia has significant potential as a clean energy.Therefore,the method has received much attention.In this work,Cu/Fe 2D bimetallic metal-organic frameworks were synthesized by a facile method applied as cathode materials without high-temperature carbonization.Bimetallic centers(Cu,Fe)with enhanced intrinsic activity demonstrated higher removal efficiency.Meanwhile,the 2D nanosheet reduced themass transfer barrier between the catalyst and nitrate and increased the reaction kinetics.Therefore,the catalysts with a 2D structure showed much better removal efficiency than other structures(3D MOFs and BulkMOFs).Under optimal conditions,Cu/Fe-2D MOF exhibited high nitrate removal efficiency(87.8%)and ammonium selectivity(89.3%)simultaneously.The ammonium yielded up to significantly 907.2μg/(hr·mg_(cat))(7793.8μg/(hr·mg_(metal)))with Faradaic efficiency of 62.8%at an initial 100 mg N/L.The catalyst was proved to have good stability and was recycled 15 times with excellent effect.DFT simulations confirm the reduced Gibbs free energy of Cu/Fe-2D MOF.This study demonstrates the promising application of Cu/Fe-2D MOF in nitrate reduction to ammonia and provides new insights for the design of efficient electrode materials.展开更多
Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;...Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;AEU for Army Engineering University of PLA),was synthesized,which shows good water and chemical stabilities.Significantly,due to channel constriction accompanied by the polar window caused by introducing nitrate ions,AEU-1 exhibits high C_(2)H_(6)/C_(2)H_(4)adsorption selectivity comparable to many famous C_(2)H_(6)-selective MOFs,making it a promising candidate for the purification of methanol-to-olefin(MTO)products.Furthermore,theoretical investigations reveal that the introduced nitrate ions in AEU-1 as the main adsorption sites could provide strong interactions between the framework and C2H6/C3H6 in the full-contacting mode,leading to an increase in the adsorption enthalpies(Qst)of C_(2)H_(6)and C_(3)H_(6),and thus further improving the C_(2)H_(6)/C_(2)H_(4)and C_(3)H_(6)/C_(2)H_(4)adsorption selectivity.Our work could open up a new avenue for constructing MOFs with inorganic polar moieties as adsorption sites for one-step C_(2)H_(4)purification and C3H6 recovery from MTO mixtures with high selectivity.展开更多
In the current work,we studied the infrared spectroscopy of neutral and cationic 2-ethoxyethanol(CH_(3)CH_(2)O CH_(2)CH_(2)OH,2-EE)using the infrared(IR)-vacuum-ultraviolet(VUV)non-resonant ionization and fragmenta-ti...In the current work,we studied the infrared spectroscopy of neutral and cationic 2-ethoxyethanol(CH_(3)CH_(2)O CH_(2)CH_(2)OH,2-EE)using the infrared(IR)-vacuum-ultraviolet(VUV)non-resonant ionization and fragmenta-tion detected IR spectroscopy(NRIFD-IR)technique.The spectral range was from 2700 cm^(−1)to 7250 cm^(−1).Upon radiation with a 118 nm laser,signals corresponding to the cationic 2-EE(m/z=90)and dissociative ioniza-tion products(m/z=72,59,46,and 45)were detected.The action IR spectra,derived from the signal variations of 2-EE and its fragments upon IR radiation,display differences,suggest-ing vibrational mode selectivity in the dissociative ionization process.To complement the ex-perimental findings,we performed density functional theory calculations at the B3LYP-D3(BJ)/def2-TZVPP level to determine the structures and anharmonic IR spectra of neutral and cationic 2-EE.The computed spectra showed good agreement with the experimental re-sults.展开更多
The methane selective oxidation was a"holy grail"reaction.However,peroxidation and low selectivity limited the application.Herein,we combined three Au contents with TiO_(2)in both encapsulation(xAu@TiO_(2))a...The methane selective oxidation was a"holy grail"reaction.However,peroxidation and low selectivity limited the application.Herein,we combined three Au contents with TiO_(2)in both encapsulation(xAu@TiO_(2))and surface-loaded(xAu/TiO_(2))ways by MOF derivation strategy,reported a catalyst 0.5Au@TiO_(2)exhibited a CH_(3)OH yield of 32.5μmol·g^(-1)·h^(-1)and a CH_(3)OH selectivity of 80.6%under catalytic conditions of only CH_(4),O_(2),and H_(2)O.Mechanically speaking,the catalytic activity was controlled by both electron-hole separation efficiency and core-shell structure.The interfacial contact between Au nanoparticles and TiO_(2)in xAu@TiO_(2)and xAu/TiO_(2)induced the formation of oxygen vacancies,with 0.5 Au content showing the highest oxygen vacancy concentration.At the same Au content,xAu@TiO_(2)generated more oxygen vacancies than xAu/TiO_(2).The oxygen vacancy acted as an effective electron cold trap,which enhanced the photogenerated carrier separation efficiency and thereby improved the catalytic activity.In-situ DRIFTs revealed that the isolated OH(non-hydrogen bond adsorption)were key species for the methane selective oxidation,playing a role in the activation of CH_(4)to^(*)CH_(3).However,an overabundance of isolated OH led to severe overoxidation.Fortunately,the core-shell structure over xAu@TiO_(2)provided a slow-release environment for isolated OH through the intermediate state of^(*)OH(hydrogen bond adsorption)to balance the formation rate and consumption rate of isolated OH,doubling the methanol yield and increasing the>29%selectivity.These results showed a new strategy for the control of the overoxidation rate via a strategy of MOF encapsulation followed by pyrolytic derivation for methane selective oxidation.展开更多
Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In...Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.展开更多
In this work,the phosphomolybdate(HPMo)modification strategy was applied to improve the N_(2) selectivity of Mn Co-BTC@SiO_(2)catalyst for the selective catalytic reduction of NO_(x),and further,the mechanism of HPMo ...In this work,the phosphomolybdate(HPMo)modification strategy was applied to improve the N_(2) selectivity of Mn Co-BTC@SiO_(2)catalyst for the selective catalytic reduction of NO_(x),and further,the mechanism of HPMo modification on enhanced catalytic performance was explored.Among Mn Co-BTC@SiO_(2-x) catalysts with different HPMo concentrations,Mn CoBTC@SiO_(2)-0.75 catalyst exhibited not only the highest NH_(3)-SCR performance(95% at 200-300℃)but also the best N_(2)selectivity(exceed 80% at 100-300℃)due to the appropriate redox capacity,greater surface acidity.X-ray photoelectron spectrometer(XPS)and temperature programmed reduction of H_(2)(H_(2)-TPR)results showed that the modification with HPMo reduced the oxidation-reduction performance of the catalyst due to electron transfer from Mo^(5+)to Mn^(4+)/Mn^(3+)and prevent the excessive oxidation of ammonia adsorption species.NH_(3)temperature-programmed desorption of(NH_(3)-TPD)results showed that the modification with HPMo could significantly improve the surface acidity and NH_(3)adsorption,which enhance the catalytic activity and N_(2)selectivity.In-situ diffused reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS)revealed that modification with HPMo increased significantly the amount of adsorbed NH_(3)species on the Bronsted acid site and C_(B)/C_(L),it suppressed the production of N_(2)O by inhibiting the production of NH species,the deep dehydrogenation of ammonia adsorption species.This study provided a simple design strategy for the catalyst to improve the low-temperature catalytic performance and N_(2)selectivity.展开更多
Reliable and selective sensing of dopamine(DA)is essential for early diagnosis of mental diseases.Among the various potential methods,nanozyme-based sensing systems have demonstrated promising sensitivity and reliabil...Reliable and selective sensing of dopamine(DA)is essential for early diagnosis of mental diseases.Among the various potential methods,nanozyme-based sensing systems have demonstrated promising sensitivity and reliability.However,owing to the lack of substrate specificity,it is challenging to selectively detect DA using nanozymes.Herein,based on the reactivity of the DA oxidation intermediates,we report a cascade colorimetric sensing system for the selective detection of DA using only a single nanozyme.It was disclosed that the oxidation product of DA catalyzed by Co-N-doped carbon sheets(Co-N-C,a common oxidase-like nanozyme),dopamine quinone(DAQ),showed significant biocatalytic electron-donating activity in the reduction of O_(2)to generate O_(2)·-.Further using O_(2)·-to oxidize3,3,5,5-tetramethylbenzidine(TMB),a colorimetric sensing platform for DA was constructed with a linear detection range of 50 nmol/L to 50μmol/L and a low limit of detection of 4 nmol/L.Thanks to the reactivity of the oxidation product,without any biometric units(such as nucleic acids,enzymes,and antibodies/antigens),the reaction selectivity of DA against other interferences(e.g.,ascorbic acid,adrenaline,5-hydroxytryptamine,and glutathione)was enhanced up to 71-fold.Beyond complicated cascade systems requiring at least two nanozymes,sophisticated artificial recognition via multiple interactions was simplified by exploiting the oxidative properties of product intermediates;thus,only a single common oxidase-like nanozyme was needed.This work offers a new strategy to enhance the selectivity of nanozymes for bioanalytical applications.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
Development of hydrothermally stable,low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge.We have prepared a metal oxide-zeolite composite catalyst by dep...Development of hydrothermally stable,low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge.We have prepared a metal oxide-zeolite composite catalyst by depositing Mn active species on a mixture support of CeO_(2)/Al_(2)O_(3) and ZSM-5.This composite catalyst is hydrothermally stable and shows improved low-temperature SCR activity and significantly reduced N_(2)O formation than the corresponding metal oxide catalyst.Comparing with a Cu-CHA catalyst,the composite catalyst has a faster response to NH_(3) injection and less NH_(3) slip.Our characterization results reveal that such an oxide-zeolite composite catalyst contains more acidic sites and Mn^(3+)species as a result of oxide-zeolite interaction,and this interaction leads to the generation of more NH_(4)^(+)species bound to the Br?nsted acid sites and more reactive NOxspecies absorbed on the Mn sites.Herein,we report our mechanistic understanding of the oxide-zeolite composite catalyst and its molecular pathway for improving the low-temperature activity and N_(2) selectivity for NH_(3)-SCR reaction.Practically,this work may provide an alternative methodology for low-temperature NO_(x) control from diesel vehicles.展开更多
Photoelectrochemical (PEC) small-molecule oxidation can selectively transform substrates into high-value-added fine chemicals and increase the rate of cathode hydrogen evolution. Nevertheless, achieving high-selectivi...Photoelectrochemical (PEC) small-molecule oxidation can selectively transform substrates into high-value-added fine chemicals and increase the rate of cathode hydrogen evolution. Nevertheless, achieving high-selectivity PEC oxidation of small molecules to produce specific products is a very challenging task. In general, selectivity can be improved by changing the surface catalyticsites of the photoanode and modulating the interfacial environments of the reactions. Herein, recent advances in approaches to improving selective PEC oxidation of small molecules are introduced. We first briefly discuss the basic concept and fundamentals of small-molecule PEC oxidation. The reported approaches to improving the performance of selective PEC oxidation of small molecules are highlighted from two aspects: (1) changing the surface properties of photoanodes by selecting suitable materials or modifying the photoanodes and (2) mediating the oxidation reactions using redox mediators. The PEC oxidation mechanism of these studies is emphasized. We also discuss the challenges in this research direction and offer a perspective on the further development of selective PEC-based small-molecule transformation.展开更多
文摘The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.
基金support from the Chinese Academy of Sciences and University of Science and Technology of China,National Key Research and Development Program of China(No.2021YFA1500402)National Natural Science Foundation of China(Nos.21571167,51502282 and 22075266)Fundamental Research Funds for the Central Universities(Nos.WK2060190053 and WK2060190100)。
文摘Efficient selective adsorption and separation using porous frameworks are critical in many industrial processes,where adsorption energy and dynamic diffusion rate are predominant factors governing selectivity.They are highly susceptible to framework charge,which plays a significant role in selective adsorption.Currently,ionic porous frameworks can be divided into two types.One of them is composed of a charged backbone and counter ions.The framework with zwitterionic channels is another type.It is composed of regular and alternating arrangements of cationic and anionic building units.Herein,we report a hydrogen-bonded ionic framework(HIF)of{(CN_(3)H_(6))_(2)[Ti(μ_(2)-O)(SO_(4))_(2)]}_nwith 1D channel exhibits unique adsorption selectivity for Ar against N_(2)and CO_(2).Density functional theory(DFT)results suggest that CO_(2)cannot be adsorbed by HIF at the experimental temperature due to a positive adsorption free energy.In addition,due to a relatively large diffusion barrier at 77 K,N_(2)molecules hardly diffuse in HIF channels,while Ar has a negligible diffusion barrier.The unique net positively-charged space in the channel is the key to the unusual phenomena,based on DFT simulations and structural analysis.The findings in this work proposes the new adsorption mechanism and provides unique perspective for special separation applications,such as isotope and noble gasses separations.
基金supported by the National Natural Science Foundation of China(Nos.22494632,22234005,and 22074064)Natural Science Foundation of Jiangsu Province(No.BK20222015).
文摘Improving the selectivity of resistive gas sensors and understanding the mechanism of gas sensors are quite significant for the design and application of gas sensors in practical application.In this work,a high selective acetone sensor based on n-n homojunction by loading ZnO quantum dots(QDs)onto ZnO nanorod(ZnO QDs@ZnO nanorod)sensing material was fabricated.The microstructure and element analysis of ZnO QDs@ZnO nanorod were characterized by transmission electron microscope,X-ray photoelectron spectroscopy(XPS),and X-ray diffraction.The experimental results showed that the sensor possesses excellent acetone selectivity(selectivity coefficient S1/S2=8.76,where S1 represents the response value of the sensor to acetone and S2 represents the response value of the sensor to interfering gas at the same concentration).The prepared sensor has the low detection limit of acetone(10 ppb).The sensing mechanism of enhanced selectivity for acetone was explored by in-situ Raman test and XPS,in which the n-n homojunction-associated conversion of lattice oxygen to surface adsorbed oxygen is proposed.Theoretical calculation demonstrates the transformation from lattice oxygen to adsorbed oxygen and the enhanced ability of acetone adsorption.The improved selectivity and the deep investigation of the mechanism provide an effective way for the design of highly selective gas sensing materials.
基金supported by the National Natural Science Foundation of China(Nos.22471093,92156012 and 22071078).
文摘Inspired by natural Ca^(2+)channels,we design and synthesize a type of artificial Ca^(2+)carriers using o-phenanthroline-oxadiazole-based foldamers.Through the incorporation of negative charges into cavity-containing foldamers,highly selective calcium ion transmembrane transport can be achieved,leading to the identification of two highly efficient Ca^(2+)carriers.Systematic investigation revealed a positive correlation between the number of negative charges on the foldamers and the foldamers‘cation-binding affinity.Furthermore,the size-selective effect,achieved through precise matching between the foldamer cavity dimensions and Ca^(2+)ion size,resulted in an unprecedented Ca^(2+)/Mg^(2+)selectivity ratio(S_(Ca/Mg)),reaching record S_(Ca/Mg) values greater than 100–the highest of all artificial Ca^(2+)carriers reported to date.Moreover,artificial Ca^(2+)carriers show high Ca^(2+)transport activity(EC_(50)=190 nM).This simple and modular approach enables tailored design of divalent cation transporters,thus providing promising applications for artificial divalent cation transporters in the fields of biochemistry and material chemistry.
文摘BACKGROUND Autism spectrum disorder(ASD)is a neurodevelopmental disorder that manifests in the first years of life,with a complex pathogenesis influenced by biological,genetic and epigenetic factors.Many children with ASD display marked food selectivity,often restricting themselves to a narrow range of foods.The problems associated with feeding children with ASD can vary widely,from mild cases that pose no immediate health risks,to more severe situations with a risk of mal-nutrition or,conversely,overeating.This scoping review aims to provide an in-depth overview of the frequency,nature and factors related to food selectivity in children with autism.AIM To comprehensively review the literature on food selectivity in ASD.METHODS A systematic review of the literature was conducted using the PubMed,Web of Science and EBSCO databases,to identify articles published in English from 2014 until 2024.Studies on a sample diagnosed with ASD and food selectivity were included.The selected databases were chosen for their broad coverage of the scientific literature.These databases represent reliable sources of high-quality articles,ensuring a comprehensive and up-to-date search.RESULTS We evaluated 222 studies on food selectivity in autism,from which duplicates were removed and unrelated titles were filtered out.Finally,9 articles were included in the review.Five articles provide a general overview of the phenomenon,analysing its nature and factors.Two studies delve into sensory sensitivity,in particular the impact of food textures,tastes and smells.Finally,two studies focus on problem behaviour during mealtimes.CONCLUSION Children with ASD have greater food selectivity than the neurotypical population.The diet should contain a greater variety of fruit,vegetables,yoghurt,while reducing the consumption of rice and pasta.
基金the National Natural Science Foundation of China(Nos.22125604,22106100,21976117,22276119)Shanghai Rising-Star Program(No.22QA1403700).
文摘Developing a high-efficiency catalyst with both superior low-temperature activity and good N_(2)selectivity is still challenging for the NH_(3)selective catalytic reduction(SCR)of NO_(x)from mobile sources.Herein,we demonstrate the improved low-temperature activity and N_(2)selectivity by regulating the redox and acidic properties of MnCe oxides supported on etched ZSM-5 supports.The etched ZSM-5 enables the highly dispersed state of MnCeOx species and strong interaction between Mn and Ce species,which promotes the reduction of CeO2,facilitates electron transfer from Mn to Ce,and generates more Mn^(4+)and Ce^(3+)species.The strong redox capacity contributes to forming the reactive nitrate species and-NH_(2)species from oxidative dehydrogenation of NH_(3).Moreover,the adsorbed NH_(3)and-NH_(2)species are the reactive intermediates that promote the formation of N_(2).This work demonstrates an effective strategy to enhance the low-temperature activity and N_(2)selectivity of SCR catalysts,contributing to the NO_(x)control for the low-temperature exhaust gas during the cold-start of diesel vehicles.
文摘Aldehydes are valuable intermediates with widespread industrial applications,and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly.Electrochemical oxidation offers a more sustainable and milder alternative;however,it faces challenges such as aldehyde overoxidation and susceptibility to base-catalyzed Cannizzaro disproportionation.Electrochemical glycerol oxidation to glyceraldehyde is a representative example,which typically requires precious metal-based electrocatalysts but still suffers from low selectivity and activity.Here,we report a metal-free oxidation strategy mediated by 2,2,6,6-tetramethylpiperidine-1-oxyl.By systematically investigating the redox thermodynamics and kinetics of TEMPO across a broad pH range,we construct a Pourbaix diagram and elucidate the relative kinetics of each reaction step.These insights allow us to explain the anomalously high apparent Faradaic efficiency(~200%)observed under acidic conditions,and identify neutral media as the optimal environment for selective glyceraldehyde production.Under optimized conditions,our system achieves a glyceraldehyde Faradaic efficiency exceeding 93%and a partial current density of 23.3 mA cm^(-2)at 0.57 V—more than doubling the performance of the best reported precious metal-based systems.Furthermore,the versatility of this strategy extends to the selective oxidation of other primary alcohols to their corresponding aldehydes with near-unity selectivity.
基金supported by National Nature Science Foundation of China(Nos.92161202 and 22121005)China Postdoctoral Science Foundation(Nos.2023M741814 and 2023M741815)+2 种基金Postdoctoral Fellowship Program of CPSF(No.GZC20231170)Natural Science Foundation of Science&Technology Department of Sichuan Province(No.2023NSFSC110)Research and Innovation Team of China West Normal University(No.KCXTD2023-1)。
文摘Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but full of great challenge.Herein,a cationic In-captured Zr-porphyrin framework(1)with nanosized pores/cages was successfully constructed and showed high structure stability.Catalytic investigations revealed that 1 displayed highly multi-selective CTH of aldehydes and ketones containing both chemo-and size selectivity for the first time.The CTH of aldehydes and ketones exhibited remarkable reductive selectivity of 99%towards C=O bonds into CH–OH in the presence of-NO_(2),-CN and C=C groups.Through tuning the reaction conditions,1 also exhibited highly selective reduction of 97%for-CHO groups in the simultaneous presence of-CHO and-COCH3groups in intra-and intermolecular settings.Remarkably,reductive selectivity towards-CHO group remained prominent among five concurrent unsaturated groups mentioned above.Additionally,the definite pore size of 1 facilitated volume control of substrates,enabling size selectivity.1 as a heterogeneous catalyst was further confirmed by leaching tests,and maintained high activity even after being used for at least six cycles.Mechanistic studies have revealed that Zr6O8clusters served as the catalytic centers and the observed chemoselectivity mainly results from the synergistic effect of distinct metal sites within 1.The heightened selectivity towards-CHO over-COCH_(3)can be attributed to the easier realization of transfer hydrogenation processes for-CHO compared to-COCH_(3).
基金supported by Natural Sciences and Engineering Research Council of Canada Strategic Grants program(463037-14)Discovery Grants program(2016-05524,2022-04881,2020-04262)。
文摘The increasing demand for electronics has led to a desire to recover rare earth elements(REEs) from nonconventional sources,including mining and liquid waste effluents.Biosorption could be a promising method for adsorbing REEs onto microalgae,but biomass immobilization and light delivery challenges remain.It was recently shown that REEs biosorb 160% more on algal biofilms than suspended biomass due to the extracellular polymeric substance(EPS) matrix that grows abundantly in biofilms.In this work,we present findings on biosorption selectivity for different REEs in sulfate solutions.The maximum adsorption capacities of Euglena mutabilis suspensions and biofilms were determined for a mixed REE sulfate solution at an equimolar initial concentration range of 0.1-1 mol/L of each REE ion.The highest adsorption capacities for the suspension are for Sm and Eu which are 57% and 46% higher,respectively,compared to the average REE adsorption capacity.The biofilms also preferentially adsorb Sm,Eu,Yb and Lu at 0.035,0.033,0.033,and 0.031 mmol/g,respectively.The impact of dissolved divalent ions of Ca,Mg,and Fe on REE adsorption was also assessed.When Ca and Mg are added in equimolar amounts to0.1-1 mmol/L solutions of equimolar La,Eu,and Yb sulfate,the amount of REEs adsorbed onto suspensions increases by 30% while when Fe is added,it decreases by 10%.No change is observed in biofilms except when Fe is added resulting in a reduction of the adsorption capacity by 40%.A possible explanation for the role of Fe is attributed to the formation of stronger bonds at the binding sites compared to Ca and Mg.
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.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.52370044 and 21976134)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(Nos.PCRRK21003 and PCRRK21001)+1 种基金Shanghai Scientific Research Plan Project(No.23ZR1467000)the State Key Laboratory of Treatments and Recycling for Organic Effluents by Adsorption in Petroleum and Chemical Industry(No.SDHY2206).
文摘Electrocatalytic reduction of nitrate to ammonia has been considered a promising and sustainable pathway for pollutant treatment and ammonia has significant potential as a clean energy.Therefore,the method has received much attention.In this work,Cu/Fe 2D bimetallic metal-organic frameworks were synthesized by a facile method applied as cathode materials without high-temperature carbonization.Bimetallic centers(Cu,Fe)with enhanced intrinsic activity demonstrated higher removal efficiency.Meanwhile,the 2D nanosheet reduced themass transfer barrier between the catalyst and nitrate and increased the reaction kinetics.Therefore,the catalysts with a 2D structure showed much better removal efficiency than other structures(3D MOFs and BulkMOFs).Under optimal conditions,Cu/Fe-2D MOF exhibited high nitrate removal efficiency(87.8%)and ammonium selectivity(89.3%)simultaneously.The ammonium yielded up to significantly 907.2μg/(hr·mg_(cat))(7793.8μg/(hr·mg_(metal)))with Faradaic efficiency of 62.8%at an initial 100 mg N/L.The catalyst was proved to have good stability and was recycled 15 times with excellent effect.DFT simulations confirm the reduced Gibbs free energy of Cu/Fe-2D MOF.This study demonstrates the promising application of Cu/Fe-2D MOF in nitrate reduction to ammonia and provides new insights for the design of efficient electrode materials.
基金supported by the Youth Autonomous Innovation Funding from Army Engineering University of PLA(KYJBJKQTZQ23005)the Basic Discipline Incubation Funding from Army Engineering University of PLA(KYJBJKQTZK23011).
文摘Based upon the thiophene-2,5-dicarboxylic acid(H_(2)Tdc),a novel[Sc_(3)(μ_(2)-OH)_(3)(CO_(2))_(4)O_(6)]n inorganic chain-based Sc-MOF with decorated nitrate ions,{[Sc_(3)(OH)_(2)(Tdc)_(3)(NO_(3))]⋅H_(2)O}_(∞)(AEU-1;AEU for Army Engineering University of PLA),was synthesized,which shows good water and chemical stabilities.Significantly,due to channel constriction accompanied by the polar window caused by introducing nitrate ions,AEU-1 exhibits high C_(2)H_(6)/C_(2)H_(4)adsorption selectivity comparable to many famous C_(2)H_(6)-selective MOFs,making it a promising candidate for the purification of methanol-to-olefin(MTO)products.Furthermore,theoretical investigations reveal that the introduced nitrate ions in AEU-1 as the main adsorption sites could provide strong interactions between the framework and C2H6/C3H6 in the full-contacting mode,leading to an increase in the adsorption enthalpies(Qst)of C_(2)H_(6)and C_(3)H_(6),and thus further improving the C_(2)H_(6)/C_(2)H_(4)and C_(3)H_(6)/C_(2)H_(4)adsorption selectivity.Our work could open up a new avenue for constructing MOFs with inorganic polar moieties as adsorption sites for one-step C_(2)H_(4)purification and C3H6 recovery from MTO mixtures with high selectivity.
基金funded by the National Natural Science Foundation of China(No.22288201)the Chinese Academy of Sciences(GJJSTD20220001)the Innovation Program for Quantum Science and Technology(No.2021ZD0303305)。
文摘In the current work,we studied the infrared spectroscopy of neutral and cationic 2-ethoxyethanol(CH_(3)CH_(2)O CH_(2)CH_(2)OH,2-EE)using the infrared(IR)-vacuum-ultraviolet(VUV)non-resonant ionization and fragmenta-tion detected IR spectroscopy(NRIFD-IR)technique.The spectral range was from 2700 cm^(−1)to 7250 cm^(−1).Upon radiation with a 118 nm laser,signals corresponding to the cationic 2-EE(m/z=90)and dissociative ioniza-tion products(m/z=72,59,46,and 45)were detected.The action IR spectra,derived from the signal variations of 2-EE and its fragments upon IR radiation,display differences,suggest-ing vibrational mode selectivity in the dissociative ionization process.To complement the ex-perimental findings,we performed density functional theory calculations at the B3LYP-D3(BJ)/def2-TZVPP level to determine the structures and anharmonic IR spectra of neutral and cationic 2-EE.The computed spectra showed good agreement with the experimental re-sults.
文摘The methane selective oxidation was a"holy grail"reaction.However,peroxidation and low selectivity limited the application.Herein,we combined three Au contents with TiO_(2)in both encapsulation(xAu@TiO_(2))and surface-loaded(xAu/TiO_(2))ways by MOF derivation strategy,reported a catalyst 0.5Au@TiO_(2)exhibited a CH_(3)OH yield of 32.5μmol·g^(-1)·h^(-1)and a CH_(3)OH selectivity of 80.6%under catalytic conditions of only CH_(4),O_(2),and H_(2)O.Mechanically speaking,the catalytic activity was controlled by both electron-hole separation efficiency and core-shell structure.The interfacial contact between Au nanoparticles and TiO_(2)in xAu@TiO_(2)and xAu/TiO_(2)induced the formation of oxygen vacancies,with 0.5 Au content showing the highest oxygen vacancy concentration.At the same Au content,xAu@TiO_(2)generated more oxygen vacancies than xAu/TiO_(2).The oxygen vacancy acted as an effective electron cold trap,which enhanced the photogenerated carrier separation efficiency and thereby improved the catalytic activity.In-situ DRIFTs revealed that the isolated OH(non-hydrogen bond adsorption)were key species for the methane selective oxidation,playing a role in the activation of CH_(4)to^(*)CH_(3).However,an overabundance of isolated OH led to severe overoxidation.Fortunately,the core-shell structure over xAu@TiO_(2)provided a slow-release environment for isolated OH through the intermediate state of^(*)OH(hydrogen bond adsorption)to balance the formation rate and consumption rate of isolated OH,doubling the methanol yield and increasing the>29%selectivity.These results showed a new strategy for the control of the overoxidation rate via a strategy of MOF encapsulation followed by pyrolytic derivation for methane selective oxidation.
基金supported by the renewable energy and hydrogen projects in National Key Research and Development Plan of China(2019YFB1505000).
文摘Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.
基金supported by the National Natural Science Foundation of China(No.U20A20130 and 21806009)the Fundamental Research Funds for the Central Universities(No.FRF-IDRY-19-020)。
文摘In this work,the phosphomolybdate(HPMo)modification strategy was applied to improve the N_(2) selectivity of Mn Co-BTC@SiO_(2)catalyst for the selective catalytic reduction of NO_(x),and further,the mechanism of HPMo modification on enhanced catalytic performance was explored.Among Mn Co-BTC@SiO_(2-x) catalysts with different HPMo concentrations,Mn CoBTC@SiO_(2)-0.75 catalyst exhibited not only the highest NH_(3)-SCR performance(95% at 200-300℃)but also the best N_(2)selectivity(exceed 80% at 100-300℃)due to the appropriate redox capacity,greater surface acidity.X-ray photoelectron spectrometer(XPS)and temperature programmed reduction of H_(2)(H_(2)-TPR)results showed that the modification with HPMo reduced the oxidation-reduction performance of the catalyst due to electron transfer from Mo^(5+)to Mn^(4+)/Mn^(3+)and prevent the excessive oxidation of ammonia adsorption species.NH_(3)temperature-programmed desorption of(NH_(3)-TPD)results showed that the modification with HPMo could significantly improve the surface acidity and NH_(3)adsorption,which enhance the catalytic activity and N_(2)selectivity.In-situ diffused reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS)revealed that modification with HPMo increased significantly the amount of adsorbed NH_(3)species on the Bronsted acid site and C_(B)/C_(L),it suppressed the production of N_(2)O by inhibiting the production of NH species,the deep dehydrogenation of ammonia adsorption species.This study provided a simple design strategy for the catalyst to improve the low-temperature catalytic performance and N_(2)selectivity.
基金supported by the National Natural Science Foundation of China(Nos.22174014 and 22074015)。
文摘Reliable and selective sensing of dopamine(DA)is essential for early diagnosis of mental diseases.Among the various potential methods,nanozyme-based sensing systems have demonstrated promising sensitivity and reliability.However,owing to the lack of substrate specificity,it is challenging to selectively detect DA using nanozymes.Herein,based on the reactivity of the DA oxidation intermediates,we report a cascade colorimetric sensing system for the selective detection of DA using only a single nanozyme.It was disclosed that the oxidation product of DA catalyzed by Co-N-doped carbon sheets(Co-N-C,a common oxidase-like nanozyme),dopamine quinone(DAQ),showed significant biocatalytic electron-donating activity in the reduction of O_(2)to generate O_(2)·-.Further using O_(2)·-to oxidize3,3,5,5-tetramethylbenzidine(TMB),a colorimetric sensing platform for DA was constructed with a linear detection range of 50 nmol/L to 50μmol/L and a low limit of detection of 4 nmol/L.Thanks to the reactivity of the oxidation product,without any biometric units(such as nucleic acids,enzymes,and antibodies/antigens),the reaction selectivity of DA against other interferences(e.g.,ascorbic acid,adrenaline,5-hydroxytryptamine,and glutathione)was enhanced up to 71-fold.Beyond complicated cascade systems requiring at least two nanozymes,sophisticated artificial recognition via multiple interactions was simplified by exploiting the oxidative properties of product intermediates;thus,only a single common oxidase-like nanozyme was needed.This work offers a new strategy to enhance the selectivity of nanozymes for bioanalytical applications.
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in part supported by BASF Environmental Catalyst and Metal Solutionsthe support of the National Natural Science Foundation of China(Nos.21976117,22125604 and 22276119)the sponsor by“Chenguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.21CGA48)。
文摘Development of hydrothermally stable,low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge.We have prepared a metal oxide-zeolite composite catalyst by depositing Mn active species on a mixture support of CeO_(2)/Al_(2)O_(3) and ZSM-5.This composite catalyst is hydrothermally stable and shows improved low-temperature SCR activity and significantly reduced N_(2)O formation than the corresponding metal oxide catalyst.Comparing with a Cu-CHA catalyst,the composite catalyst has a faster response to NH_(3) injection and less NH_(3) slip.Our characterization results reveal that such an oxide-zeolite composite catalyst contains more acidic sites and Mn^(3+)species as a result of oxide-zeolite interaction,and this interaction leads to the generation of more NH_(4)^(+)species bound to the Br?nsted acid sites and more reactive NOxspecies absorbed on the Mn sites.Herein,we report our mechanistic understanding of the oxide-zeolite composite catalyst and its molecular pathway for improving the low-temperature activity and N_(2) selectivity for NH_(3)-SCR reaction.Practically,this work may provide an alternative methodology for low-temperature NO_(x) control from diesel vehicles.
基金the National Natural Science Foundation of China (No. 22136005)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB36000000).
文摘Photoelectrochemical (PEC) small-molecule oxidation can selectively transform substrates into high-value-added fine chemicals and increase the rate of cathode hydrogen evolution. Nevertheless, achieving high-selectivity PEC oxidation of small molecules to produce specific products is a very challenging task. In general, selectivity can be improved by changing the surface catalyticsites of the photoanode and modulating the interfacial environments of the reactions. Herein, recent advances in approaches to improving selective PEC oxidation of small molecules are introduced. We first briefly discuss the basic concept and fundamentals of small-molecule PEC oxidation. The reported approaches to improving the performance of selective PEC oxidation of small molecules are highlighted from two aspects: (1) changing the surface properties of photoanodes by selecting suitable materials or modifying the photoanodes and (2) mediating the oxidation reactions using redox mediators. The PEC oxidation mechanism of these studies is emphasized. We also discuss the challenges in this research direction and offer a perspective on the further development of selective PEC-based small-molecule transformation.
