Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits ina...Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen peroxide.Herein,the adsorption of Co-N-C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band theory.The heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant(MoC/Co-N-C)are engineered to successfully modulate the d band center of active Co-N-C sites,resulting in a remarkably enhanced electrocatalysis performance.The optimally performing MoC/Co-N-C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry,featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction(ORR)and low overpotential of 370 mV for the oxygen evolution reaction(OER)at 10 mA cm^(-2).The zinc air batteries with the MoC/Co-N-C catalyst demonstrate a large power density of 180 mW cm^(-2)and a long cycling lifespan(2000 cycles).The density functional theory calculations with Hubbard correction(DFT+U)reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with"single site double adsorption"mode.展开更多
The on-board methanol steam reforming(MSR) has long been considered as an effective approach to insitu produce hydrogen for fuel cell vehicles(FCVs). However, the conventional MSR catalyst pellets suffer from easy bre...The on-board methanol steam reforming(MSR) has long been considered as an effective approach to insitu produce hydrogen for fuel cell vehicles(FCVs). However, the conventional MSR catalyst pellets suffer from easy breakage during the vehicle movement, leading to increased pressure drop and reduced system stability. Herein, we introduce an integrated method to prepare the highly controlled structured catalysts based on coupled processes: direct prototyping the structured substrate using digital light processing(DLP) 3D printing technology, in-situ dynamic crystallization of active components assisted by magnetic resonance imaging(MRI) and calcination. The synthesized catalyst owns a gradient layer of active component, and exhibits better MSR performance, higher mechanical strength, reduced pressure drop, higher Cu dispersion and better adhesion of active compounds when compared with the conventional powder and pellet catalysts. The demonstrated successful application proves the feasibility of developed method,which has great potential to be used for preparing precisely other monolithic catalysts with customized structures.展开更多
Electrocatalyst designs based on oxophilic foreign atoms are considered a promising approach for developing efficient pH-universal hydrogen evolution reaction(HER)electrocatalysts by overcoming the sluggish alkaline H...Electrocatalyst designs based on oxophilic foreign atoms are considered a promising approach for developing efficient pH-universal hydrogen evolution reaction(HER)electrocatalysts by overcoming the sluggish alkaline HER kinetics.Here,we design ternary transition metals-based nickel telluride(Mo WNi Te)catalysts consisting of high valence non-3d Mo and W metals and oxophilic Te as a first demonstration of non-precious heterogeneous electrocatalysts following the bifunctional mechanism.The Mo WNi Te showed excellent HER catalytic performance with overpotentials of 72,125,and 182 mV to reach the current densities of 10,100,and 1000 mA cm^(-2),respectively,and the corresponding Tafel slope of 47,52,and 58 mV dec-1in alkaline media,which is much superior to commercial Pt/C.Additionally,the HER performance of Mo WNi Te is well maintained up to 3000 h at the current density of 100 mA cm^(-2).It is further demonstrated that the Mo WNi Te exhibits remarkable HER activities with an overpotential of 45 mV(31 mV)and Tafel slope of 60 mV dec-1(34 mV dec-1)at 10 mA cm^(-2)in neutral(acid)media.The superior HER performance of Mo WNi Te is attributed to the electronic structure modulation,inducing highly active low valence states by the incorporation of high valence non-3d transition metals.It is also attributed to the oxophilic effect of Te,accelerating water dissociation kinetics through a bifunctional catalytic mechanism in alkaline media.Density functional theory calculations further reveal that such synergistic effects lead to reduced free energy for an efficient water dissociation process,resulting in remarkable HER catalytic performances within universal pH environments.展开更多
The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging.In this study,acidic poly(ionic liquid)s with swelling ability(SAPILs)were designe...The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging.In this study,acidic poly(ionic liquid)s with swelling ability(SAPILs)were designed and synthesized via the free radical copolymerization of ionic liquid monomers,sodium p-styrenesulfonate,and crosslinkers,followed by acidification.The 31P nuclear magnetic resonance chemical shifts of adsorbed trimethylphosphine oxide indicated that the synthesized SAPILs presented moderate and single acid strength.The thermogravimetric analysis results in the temperature range of 300–345°C revealed that the synthesized SAPILs were more stable than the commercial resin Amberlite IR-120(H)(245°C).Cryogenic scanning electron microscopy testing demonstrated that SAPILs presented unique three-dimensional(3D)honeycomb structure in water,which was ascribed to the swelling-induced self-assembly of the molecules.Moreover,we used SAPILs with micron-sized honeycomb structure in water as catalysts for the hydrolysis of cyclohexyl acetate to cyclohexanol,and determined that their catalytic activity was much higher than that of homogeneous acid catalysts.The equilibrium concentrations of all reaction components inside and outside the synthesized SAPILs were quantitatively analyzed using a series of simulated reaction mixtures.Depending on the reaction mixture,the concentration of cyclohexyl acetate inside SAPIL-1 was 7.5–23.3 times higher than that outside of it,which suggested the high enrichment ability of SAPILs for cyclohexyl acetate.The excellent catalytic performance of SAPILs was attributed to their 3D honeycomb structure in water and high enrichment ability for cyclohexyl acetate,which opened up new avenues for designing highly efficient heterogeneous acid catalysts that could eventually replace conventional homogeneous acid catalysts.展开更多
To reduce greenhouse gas emission from oil and gas production,it is essential to better convert methane to useful chemicals(rather) than to flare it.Conversion of methane to liquid oxygenates(mainly methanol) has attr...To reduce greenhouse gas emission from oil and gas production,it is essential to better convert methane to useful chemicals(rather) than to flare it.Conversion of methane to liquid oxygenates(mainly methanol) has attracted extensive attention and countless efforts have been made;however,running this reaction in a green,efficient,and practical way has remained elusive.The novel catalyst and oxidants play a critical role in activating methane and converting it to oxygenates(methanol).In this review,the work of commonly used oxidants for methane partial oxidation have been summarized,in which,earth abundant oxidants,O;and H;O are promising.Moreover,H;or CO can activate O;to produce H;O;that catalyzes methane partial oxidation more efficiently and selectively than O;or H;O.Therefore,the work of using reducing agent,such as CO and H;have been reviewed,focusing on rational catalyst design that features multifunction(H;O;production and CH;activation).The novel catalyst design has advanced this reaction towards practicality with green oxidants and H;using zeolites-based catalyst.Environmentally friendly zeolite preparation methods and novel two-dimensional(2 D) zeolites that can reduce waste,improve synthesis and catalytical performance substantially are also reviewed in this work to provide insights for a more comprehensive approach to meet the environment protection needs.展开更多
We for the first time systematically studied the structures and electrochemical nitrogen reduction reaction properties of two-dimensional single transition-metal anchored square tetracyanoquinodimethane monolayers(lab...We for the first time systematically studied the structures and electrochemical nitrogen reduction reaction properties of two-dimensional single transition-metal anchored square tetracyanoquinodimethane monolayers(labeled as:TM-sTCNQ,TM=3d,4d,5d series transition metals)by employing density functional theory method.Through highthroughput screenings and full reaction path researches,two promising electrochemical nitrogen reduction reaction catalysts Nb-sTCNQ and MosTCNQ have been obtained.The nitrogen reduction reaction onset potential on Nb-sTCNQ is as low as−0.48 V.Furthermore,the Nb-sTCNQ catalyst can quickly desorb NH3 produced with a free energy of 0.65 eV,giving Nb-sTCNQ excellent catalytic cycle performance.The high catalytic activity of the two materials might be attributed to the effective charge transfer between the active center and adsorbed N_(2),which enables the active center to adsorb and activate inert N_(2)molecules well,and the reduction processes require small energy input(i.e.,the maximum free energy changes are small).This work provides insights for finding highly efficient,stable,and low-cost nitrogen reduction reaction electrocatalysts.We hope our results can promote further experimental and theoretical research of this field.展开更多
(D, L)-Lactide (LA) was first polymerized with one component of rare earth catalysts [Nd(naph)(3), Nd(oct)(3), Nd(O-iPr)(3), Nd(AcAc)(3), Y(AcAc)(3), Sm(AcAc)(3), Er(AcAc)(3))] respectively in solution and in melt sta...(D, L)-Lactide (LA) was first polymerized with one component of rare earth catalysts [Nd(naph)(3), Nd(oct)(3), Nd(O-iPr)(3), Nd(AcAc)(3), Y(AcAc)(3), Sm(AcAc)(3), Er(AcAc)(3))] respectively in solution and in melt state. The effects of [Cat]/[La] molar ratio, solvents, polymerization time, temperature, various rare earth Elements and ligands were investigated in detail. The results showed that both the conversion of polymerization and the molecular weight (MW) of poly (D, L-Lactide) (PLA) in melt polymerization are higher than that in solution polymerization, but the polymerization rate in melt was lower than in solution. The molecular weight distribution (MWD) of PLA is broader with increasing temperature. X-ray study indicated that PLA obtained by Nd(AcAc)(3) in melt polymerization is an amorphous polymer.展开更多
The cross-metathesis degradation of poly(styrene-co-butadiene) (styrene, 30 wt%) (SB-1) and poly(styrene-co-butadiene) (styrene, 21 wt%) (SB- 2) in the presence of essential oils and d-limo-nene as chain transfer agen...The cross-metathesis degradation of poly(styrene-co-butadiene) (styrene, 30 wt%) (SB-1) and poly(styrene-co-butadiene) (styrene, 21 wt%) (SB- 2) in the presence of essential oils and d-limo-nene as chain transfer agents (CTAs) using Rualkylidene catalysts (PCy3)2(Cl)2Ru = CHPh (I) and (1,3-diphenyl-4,5-dihydroimidazol-2-ylidene) (PCy3)Cl2Ru=CHPh (II) was studied. Terpene-terminated butadiene oligomers and polystyrene blocks were obtained as products of the degradation of SB-1 and SB-2. Catalysts I and II showed high activity in the degradation of SB copolymers to produce the low molecular weight products (Mn = 276 - 335 g·mol-1) and yields ranging from 91% - 95%. The cross-metathesis degradation of copolymers in organic solvents and in citrus oils (mandarin, orange and lemon oils) proceeded with similar efficiency and resulted in the same molecular weight butadiene oligomers. According to GS/MS (EI) analysis, the main products of the degradation of SB-1 copolymer with d-limonene were limonene-terminated oligomers of series Am (m = 1 - 4).展开更多
The Biginelli-type compounds 4,5,8a-triarylhexahydropyrimido[4,5-d]pyrimidine-2,7（1H,3H）-diones were synthesized by a one-pot three-component reaction using sulfated tin oxide as a reusable catalyst. This method has...The Biginelli-type compounds 4,5,8a-triarylhexahydropyrimido[4,5-d]pyrimidine-2,7（1H,3H）-diones were synthesized by a one-pot three-component reaction using sulfated tin oxide as a reusable catalyst. This method has the advantages of high yields, short reaction time, simple starting materials and reusability of catalyst for several times.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21975163)the Shenzhen Innovative Research Team Program(KQTD20190929173914967)the Senior Talent Research Start-up Fund of Shenzhen University(000265)。
文摘Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good durability.However,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen peroxide.Herein,the adsorption of Co-N-C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band theory.The heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant(MoC/Co-N-C)are engineered to successfully modulate the d band center of active Co-N-C sites,resulting in a remarkably enhanced electrocatalysis performance.The optimally performing MoC/Co-N-C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry,featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction(ORR)and low overpotential of 370 mV for the oxygen evolution reaction(OER)at 10 mA cm^(-2).The zinc air batteries with the MoC/Co-N-C catalyst demonstrate a large power density of 180 mW cm^(-2)and a long cycling lifespan(2000 cycles).The density functional theory calculations with Hubbard correction(DFT+U)reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with"single site double adsorption"mode.
基金supported by the Youth Innovation Promotion Association of Chinese Academy of Sciencesthe Key Technical Personnel of Chinese Academy of Sciences+1 种基金the STS Program of Chinese Academy of Sciences (No. KFJJ-STS-SCYD-302)the National Natural Science Foundation of China (22108288)。
文摘The on-board methanol steam reforming(MSR) has long been considered as an effective approach to insitu produce hydrogen for fuel cell vehicles(FCVs). However, the conventional MSR catalyst pellets suffer from easy breakage during the vehicle movement, leading to increased pressure drop and reduced system stability. Herein, we introduce an integrated method to prepare the highly controlled structured catalysts based on coupled processes: direct prototyping the structured substrate using digital light processing(DLP) 3D printing technology, in-situ dynamic crystallization of active components assisted by magnetic resonance imaging(MRI) and calcination. The synthesized catalyst owns a gradient layer of active component, and exhibits better MSR performance, higher mechanical strength, reduced pressure drop, higher Cu dispersion and better adhesion of active compounds when compared with the conventional powder and pellet catalysts. The demonstrated successful application proves the feasibility of developed method,which has great potential to be used for preparing precisely other monolithic catalysts with customized structures.
基金supported through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2022M3H4A1A04096478)the support from the Supercomputing Center of Wuhan University。
文摘Electrocatalyst designs based on oxophilic foreign atoms are considered a promising approach for developing efficient pH-universal hydrogen evolution reaction(HER)electrocatalysts by overcoming the sluggish alkaline HER kinetics.Here,we design ternary transition metals-based nickel telluride(Mo WNi Te)catalysts consisting of high valence non-3d Mo and W metals and oxophilic Te as a first demonstration of non-precious heterogeneous electrocatalysts following the bifunctional mechanism.The Mo WNi Te showed excellent HER catalytic performance with overpotentials of 72,125,and 182 mV to reach the current densities of 10,100,and 1000 mA cm^(-2),respectively,and the corresponding Tafel slope of 47,52,and 58 mV dec-1in alkaline media,which is much superior to commercial Pt/C.Additionally,the HER performance of Mo WNi Te is well maintained up to 3000 h at the current density of 100 mA cm^(-2).It is further demonstrated that the Mo WNi Te exhibits remarkable HER activities with an overpotential of 45 mV(31 mV)and Tafel slope of 60 mV dec-1(34 mV dec-1)at 10 mA cm^(-2)in neutral(acid)media.The superior HER performance of Mo WNi Te is attributed to the electronic structure modulation,inducing highly active low valence states by the incorporation of high valence non-3d transition metals.It is also attributed to the oxophilic effect of Te,accelerating water dissociation kinetics through a bifunctional catalytic mechanism in alkaline media.Density functional theory calculations further reveal that such synergistic effects lead to reduced free energy for an efficient water dissociation process,resulting in remarkable HER catalytic performances within universal pH environments.
文摘The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging.In this study,acidic poly(ionic liquid)s with swelling ability(SAPILs)were designed and synthesized via the free radical copolymerization of ionic liquid monomers,sodium p-styrenesulfonate,and crosslinkers,followed by acidification.The 31P nuclear magnetic resonance chemical shifts of adsorbed trimethylphosphine oxide indicated that the synthesized SAPILs presented moderate and single acid strength.The thermogravimetric analysis results in the temperature range of 300–345°C revealed that the synthesized SAPILs were more stable than the commercial resin Amberlite IR-120(H)(245°C).Cryogenic scanning electron microscopy testing demonstrated that SAPILs presented unique three-dimensional(3D)honeycomb structure in water,which was ascribed to the swelling-induced self-assembly of the molecules.Moreover,we used SAPILs with micron-sized honeycomb structure in water as catalysts for the hydrolysis of cyclohexyl acetate to cyclohexanol,and determined that their catalytic activity was much higher than that of homogeneous acid catalysts.The equilibrium concentrations of all reaction components inside and outside the synthesized SAPILs were quantitatively analyzed using a series of simulated reaction mixtures.Depending on the reaction mixture,the concentration of cyclohexyl acetate inside SAPIL-1 was 7.5–23.3 times higher than that outside of it,which suggested the high enrichment ability of SAPILs for cyclohexyl acetate.The excellent catalytic performance of SAPILs was attributed to their 3D honeycomb structure in water and high enrichment ability for cyclohexyl acetate,which opened up new avenues for designing highly efficient heterogeneous acid catalysts that could eventually replace conventional homogeneous acid catalysts.
文摘To reduce greenhouse gas emission from oil and gas production,it is essential to better convert methane to useful chemicals(rather) than to flare it.Conversion of methane to liquid oxygenates(mainly methanol) has attracted extensive attention and countless efforts have been made;however,running this reaction in a green,efficient,and practical way has remained elusive.The novel catalyst and oxidants play a critical role in activating methane and converting it to oxygenates(methanol).In this review,the work of commonly used oxidants for methane partial oxidation have been summarized,in which,earth abundant oxidants,O;and H;O are promising.Moreover,H;or CO can activate O;to produce H;O;that catalyzes methane partial oxidation more efficiently and selectively than O;or H;O.Therefore,the work of using reducing agent,such as CO and H;have been reviewed,focusing on rational catalyst design that features multifunction(H;O;production and CH;activation).The novel catalyst design has advanced this reaction towards practicality with green oxidants and H;using zeolites-based catalyst.Environmentally friendly zeolite preparation methods and novel two-dimensional(2 D) zeolites that can reduce waste,improve synthesis and catalytical performance substantially are also reviewed in this work to provide insights for a more comprehensive approach to meet the environment protection needs.
基金support from the National Natural Science Foundation of China(22073033,21873032,21673087,21903032)startup fund(2006013118 and 3004013105)from Huazhong University of Science and Technology+5 种基金the Fundamental Research Funds for the Central Universities(2019kfyRCPY116)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003)support from Guangdong Basic and Applied Basic Research Foundation(2021A1515010382)the computational resources from the computing cluster at the Key Laboratory of Theoretical Chemistry of Environment,Ministry of Education&School of Chemistry,South China Normal UniversityThe work was carried out at the LvLiang Cloud Computing Center of China,and the calculations were performed on TianHe-2The computing work in this paper is supported by the Public Service Platform of High Performance Computing by Network and Computing Center of HUST.
文摘We for the first time systematically studied the structures and electrochemical nitrogen reduction reaction properties of two-dimensional single transition-metal anchored square tetracyanoquinodimethane monolayers(labeled as:TM-sTCNQ,TM=3d,4d,5d series transition metals)by employing density functional theory method.Through highthroughput screenings and full reaction path researches,two promising electrochemical nitrogen reduction reaction catalysts Nb-sTCNQ and MosTCNQ have been obtained.The nitrogen reduction reaction onset potential on Nb-sTCNQ is as low as−0.48 V.Furthermore,the Nb-sTCNQ catalyst can quickly desorb NH3 produced with a free energy of 0.65 eV,giving Nb-sTCNQ excellent catalytic cycle performance.The high catalytic activity of the two materials might be attributed to the effective charge transfer between the active center and adsorbed N_(2),which enables the active center to adsorb and activate inert N_(2)molecules well,and the reduction processes require small energy input(i.e.,the maximum free energy changes are small).This work provides insights for finding highly efficient,stable,and low-cost nitrogen reduction reaction electrocatalysts.We hope our results can promote further experimental and theoretical research of this field.
基金This work was supported by the National Natural Science Foundation of China and the Laboratory of Rare-earth Chemistry and Physics,Changchun Institute of Applied Chemistry,Academia Sinica
文摘(D, L)-Lactide (LA) was first polymerized with one component of rare earth catalysts [Nd(naph)(3), Nd(oct)(3), Nd(O-iPr)(3), Nd(AcAc)(3), Y(AcAc)(3), Sm(AcAc)(3), Er(AcAc)(3))] respectively in solution and in melt state. The effects of [Cat]/[La] molar ratio, solvents, polymerization time, temperature, various rare earth Elements and ligands were investigated in detail. The results showed that both the conversion of polymerization and the molecular weight (MW) of poly (D, L-Lactide) (PLA) in melt polymerization are higher than that in solution polymerization, but the polymerization rate in melt was lower than in solution. The molecular weight distribution (MWD) of PLA is broader with increasing temperature. X-ray study indicated that PLA obtained by Nd(AcAc)(3) in melt polymerization is an amorphous polymer.
文摘The cross-metathesis degradation of poly(styrene-co-butadiene) (styrene, 30 wt%) (SB-1) and poly(styrene-co-butadiene) (styrene, 21 wt%) (SB- 2) in the presence of essential oils and d-limo-nene as chain transfer agents (CTAs) using Rualkylidene catalysts (PCy3)2(Cl)2Ru = CHPh (I) and (1,3-diphenyl-4,5-dihydroimidazol-2-ylidene) (PCy3)Cl2Ru=CHPh (II) was studied. Terpene-terminated butadiene oligomers and polystyrene blocks were obtained as products of the degradation of SB-1 and SB-2. Catalysts I and II showed high activity in the degradation of SB copolymers to produce the low molecular weight products (Mn = 276 - 335 g·mol-1) and yields ranging from 91% - 95%. The cross-metathesis degradation of copolymers in organic solvents and in citrus oils (mandarin, orange and lemon oils) proceeded with similar efficiency and resulted in the same molecular weight butadiene oligomers. According to GS/MS (EI) analysis, the main products of the degradation of SB-1 copolymer with d-limonene were limonene-terminated oligomers of series Am (m = 1 - 4).
文摘The Biginelli-type compounds 4,5,8a-triarylhexahydropyrimido[4,5-d]pyrimidine-2,7（1H,3H）-diones were synthesized by a one-pot three-component reaction using sulfated tin oxide as a reusable catalyst. This method has the advantages of high yields, short reaction time, simple starting materials and reusability of catalyst for several times.
