In this work,we proposed a strategy for the hydrolysis of native corn starch after the treatment of corn starch in an ionic liquid aqueous solution,and it is an awfully“green”and simple means to obtain starch with l...In this work,we proposed a strategy for the hydrolysis of native corn starch after the treatment of corn starch in an ionic liquid aqueous solution,and it is an awfully“green”and simple means to obtain starch with low molecular weight and amorphous state.X-ray diffraction results revealed that the natural starch crystalline region was largely disrupted by ionic liquid owing to the broken intermolecular and intramolecular hydrogen bonds.After hydrolysis,the morphology of starch changed from particles of native corn starch into little pieces,and their molecular weight could be effectively regulated during the hydrolysis process,and also the hydrolyzed starch samples exhibited decreased thermal stability with the extension of hydrolysis time.This work would counsel as a powerful tool for the development of native starch in realistic applications.展开更多
Recent studies have confirmed the critical and essential role of elemental hydrolysis in metallogenic processes,such as metal migration and precipitation.However,the kinetic processes,characteristics,and formation mec...Recent studies have confirmed the critical and essential role of elemental hydrolysis in metallogenic processes,such as metal migration and precipitation.However,the kinetic processes,characteristics,and formation mechanisms of hydrolyzed precipitates require further comprehensive investigation.This paper is based on a systematic investigation of the hydrolysis mechanisms of Pb and Zn in various systems under ambient temperature and pressure,the storage conditions of the hydrolyzed precipitates,and the characterization of these precipitates.The results indicate that the hydrolysis behaviors of Pb and Zn exhibit significant differences across various systems.Within the monometallic regime,there is a pronounced disparity in the hydrolysis rates between Pb ions and Zn ions.Pb ions demonstrate a substantially higher degree of hydrolysis,a trend that persists over time and remains largely unaffected by the fluid retention or isolation"phenomenon in the surrounding environment.Both hydrolytic precipitation rates were observed to decrease in the mixed system,with Zn ions exhibiting less reduction than Pb ions.After hydrolysis,hydrolyzed precipitates can remain in the fluid environment for extended periods of time,which can lead to re-dissolution.Over time,this re-dissolution can increase,eventually leading to significant loss of hydrolyzed precipitates.The hydrolyzed precipitates obtained from the experiments primarily consisted of alkaline carbonates of Pb and Zn.Notably,the crystalline characteristics of the hydrolysis products of Pb and Zn ions exhibited significant differences across various experimental systems;however,the crystallographic characteristics of the primary hydrolysis products are essentially identical to those of their corresponding natural counterparts.Based on the findings from physical phase analysis and previous research,it is concluded that the hydrolysis process consists of three main stages:oxides/hydroxides,carbonates,and alkali carbonates.In the Pb-Zn-NaCl-H_(2)O system,the proportion of the basic carbonate products of Pb and Zn is 6:2.This research offers an in-depth analysis of the hydrolysis dynamics of lead and zinc under ambient temperature and pressure conditions.Furthermore,it characterizes the crystallization features of the hydrolyzed precipitates and reconstructs the three stages of the formation process.This study holds significant scientific value for understanding the metallogenic mechanisms of Pb and Zn.展开更多
With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysi...With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.展开更多
Ammonia borane(AB)has received much attention as an environmentally friendly,non-toxic,room temperature stable hydrogen storage material with high hydrogen content of 19.6%.However,its hydrolysis for hydrogen producti...Ammonia borane(AB)has received much attention as an environmentally friendly,non-toxic,room temperature stable hydrogen storage material with high hydrogen content of 19.6%.However,its hydrolysis for hydrogen production at room-temperature is kinetically slow and requires precious metal catalysts.In this work,it is found that the prepared Raney Ni W-r treated with high concentration of NaOH(6.25 mol/L)at 110℃exhibited excellent catalytic performance for AB hydrolysis at room temperature.The Raney Ni W-r can promote the AB complete hydrolysis within 60 s under basic condition at small sized trials,even higher than that of the 20%Pt/C catalyst.Its apparent activation energy at room temperature is only 26.6 kJ/mol and the turnover frequency(TOF)value is as high as 51.42 min-1.Owing to its high density and magnetic properties,the catalyst is very easy for magnetic separation.Furthermore,possible mechanism of the hydrolytic reaction of AB based on experimental results is proposed.As a well-established industrial catalyst,Raney Ni has been prepared on a large scale at low cost.This study provides a promising pathway for the large-scale preparation of low-cost and recyclable catalysts for AB hydrolysis.展开更多
An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights...An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights of the pristine PLLA(crystalline part),single stem,and single cluster were determined by gel permeation chromatography(GPC)according to their evolution during alkali hydrolysis.The maximum-folding-number(in a single cluster)and minimum-cluster-number(in one polymer chain)were obtained using these molecular weights.With the help of two numbers,the chain folding and traversing during the melt crystallization process(at 120℃)of PLLA can be described as follows.Statistically,in a single polymer chain,there are at least 2 clusters consisting of up to 6.5 stems in each of them,while the rest of the polymer chain contributes to amorphous regions.Our results provide a new strategy for the investigation and fundamental understanding of the melt crystallization of PLLA.展开更多
The efficient and cost-effective implementation of ammonia borane(AB)hydrolysis dehydrogenation for hydrogen storage is crucial.This study investigated the role of solid acid Amberlyst-15(A-15)for hydrogen evolution f...The efficient and cost-effective implementation of ammonia borane(AB)hydrolysis dehydrogenation for hydrogen storage is crucial.This study investigated the role of solid acid Amberlyst-15(A-15)for hydrogen evolution from AB hydrolysis.Notably,AB hydrogen evolution rate can reach 194.15 ml·min^(-1)at 30℃,with a low apparent activation energy of 8.20 kJ·mol^(-1).After five cycles of reuse,the reaction involving A-15 could keep a conversion rate of about 93%.The AB hydrolysis follows quasi first-order kinetics with respect to the AB concentration and quasi zero-order kinetics with respect to the A-15 mass.According to the characterization results of XRD,ATR-FTIR,and in-situ MS,the boric acid was the dominant hydrolyzate,while water as a hydrogen donor in this reaction.Furthermore,based on the reasoning that hydrogen bonds between A-15 and AB(aq)promotes the diffusion of AB,release of H2 and the cleavage of O-H bond of H2O,a possible mechanism was proposed.展开更多
The high hydrogen desorption density(19.6 wt%)of ammonia borane(AB)makes it one of the most promising chemical hydrogen storage materials.Developing cost-effective catalysts is the key for accelerating the hydrolysis ...The high hydrogen desorption density(19.6 wt%)of ammonia borane(AB)makes it one of the most promising chemical hydrogen storage materials.Developing cost-effective catalysts is the key for accelerating the hydrolysis of AB.Herein,we present a straightforward synthesis method for the Cu_(2)O decorated CoO catalyst derived from ZIF-67 precursors using carbothermal shock(~1 s)in air.The obtained results demonstrate that a small amount of Cu_(2)O doping into CoO synergistically enhances AB hydrolysis,resulting in an almost fivefold increase in turnover frequency(TOF=97 molH_(2)molCoO-1min-1at 298 K).Further studies indicated that the incorporation of Cu_(2)O alters the electronic distribution of the surface of catalysts,introducing more oxygen vacancies and increasing the pyridinic nitrogen content.The increased oxygen vacancies effectively enhanced the adsorption and activation ability of active sites for reactants(H_(2)O and AB),while the targeting effect of pyridinic nitrogen enhances the dispersion of the catalyst.Theoretical analysis reveals that CoO plays a key role in the dissociation of H_(2)O,while minor doping with Cu_(2)O substantially reduces the dissociation energy barrier of AB.This research provides a novel strategy for the design and efficient preparation of AB hydrolysis catalysts for efficient hydrogen production.展开更多
About 70%of the flue gas in the iron-steel industry has achieved multi-pollutant ultra-low emissions in China until 2023,and then the blast furnace gas purification has become the control step and bottleneck.Our resea...About 70%of the flue gas in the iron-steel industry has achieved multi-pollutant ultra-low emissions in China until 2023,and then the blast furnace gas purification has become the control step and bottleneck.Our research group has designed and constructed the world’s first blast furnace gas desulfurization pilot plant with the scale of 2000 Nm^(3)/h in October 2021.The pilot plant is a two-step combined desulfurization device including catalytic hydrolysis of carbonyl sulfur(COS)and absorption-oxidation of H_(2)S,continuously running for 120 days.In the hydrolysis system,one reason for catalyst deactivation has been verified from the sulfur deposition.HCN in blast furnace gas can be hydrolyzed on the hydrolysis catalyst to produce the nitrogen deposition,which is one of the reasons for catalyst deactivation and has never been found in previous studies.The deposition forms of S and N elements are determined,S element forms elemental sulfur and sulfate,while N element forms-NH_(2)and NH_(4)^(+).In the absorption-oxidation system,the O_(2)loading and the residence time have been optimized to control the oxidation of HS^(−)to produce elemental sulfur instead of by-product S_(2)O_(3)^(2−).The balance and distribution of S and N elements have been calculated for thewholemulti-phase system,approximately 84.4%of the sulfur is converted to solid sulfur product,about 1.3%of the sulfur and 19.2%of N element are deposited on the hydrolysis catalyst.The pilot plant provides technical support formulti-pollutant control of blast furnace.展开更多
Immobilization of alcalase on a ZIF-L(A@ZIF-L)support was explored for its potential application in producing hydrolysates of proteins extracted from microalgae.The immobilized enzyme was characterized using FTIR,XRD,...Immobilization of alcalase on a ZIF-L(A@ZIF-L)support was explored for its potential application in producing hydrolysates of proteins extracted from microalgae.The immobilized enzyme was characterized using FTIR,XRD,SEM,and TGA,and the maximum adsorption capacity was found to be 672.1±5.5 mg g^(-1)at 40℃.Adsorption equilibrium data indicated that alcalase physically adsorbed onto the ZIF-L,with the isotherm well described by the Freundlich model.The adsorption kinetics aligned best with the pseudo-first order model,suggesting that both film and intraparticle diffusion were significant.The hydrolytic activity of the immobilized A@ZIF-L was initially tested using BSA as a substrate.A diffusion-reaction model was developed and numerically solved to describe the reaction,with results confirming the presence of mass transfer limitations in the early stages of hydrolysis.The stability of the immobilized enzyme was demonstrated by retaining over 90%of its initial activity after being stored at 4℃ for 70 days.Furthermore,the immobilized A@ZIF-L was used to hy-drolyze protein extracts derived from Scenedesmus sp.microalgae.The bioactivity of the resulting protein hy-drolysates was characterized,showing a total phenolic content of 29.1±0.6 mg GAE g^(-1)and a radical scavenging activity of 82.75±2.20%.These findings highlight the potential of Alcalase-based biocatalysts for applications in the food industry.展开更多
The hydrolysis behavior of CaMg_(2)In_(0.1),CaMg_(2)In_(0.3),CaMg_(2)In_(0.5),and CaMg_(2)In_(0.7)ternary alloys in an MgCl_(2) solution following casting and hydrogenation were investigated.The hydrolysis mechanism o...The hydrolysis behavior of CaMg_(2)In_(0.1),CaMg_(2)In_(0.3),CaMg_(2)In_(0.5),and CaMg_(2)In_(0.7)ternary alloys in an MgCl_(2) solution following casting and hydrogenation were investigated.The hydrolysis mechanism of these alloys is elucidated through an analysis of microstructure,phase composition,and kinetics before and after hydrolysis.The nucleation-growth Avrami model is employed to accurately model the hydrolysis kinetics,revealing improved hydrolysis yields and reaction rates following hydrogenation.Notably,CaMg_(2)In_(0.1)has demonstrated exceptional hydrolysis characteristics,exhibiting a yield of 1140 mL/g,an initial hydrolysis rate of 113 mL/g·s,and an activation energy of 24.3±1.7 kJ·mol^(-1).The yield of H-CaMg_(2)In_(0.1)further escalates to 1800 mL/g with a rate of 221 mL/g·s,attributed to the formation of Ca_(4)Mg_(3)H_(14)and In phases subsequent to the hydrogenation of In_(2)Ca and Mg_(3)In phases in the alloy.These newly formed phases act as catalysts and actively participate in the hydrolysis process,providing active sites for hydrogen production,thus enhancing hydrolysis yields and kinetics.It is observed that with increasing In content,the order of hydrolysis performance of the alloy is as follows:CaMg_(2)In_(0.1)>CaMg_(2)In_(0.3)>CaMg_(2)In_(0.5)>CaMg_(2)In_(0.7),consistent with the trend after hydrogenation.These findings indicate that the addition of In significantly enhances the hydrolysis performance of CaMg_(2)alloys,offering a promising strategy for preparing magnesium-based alloys with high yields and favorable kinetic properties.展开更多
Enhancing the catalytic hydrolysis efficiency of microcystins(MCs)at ambient temperature has been a persistent challenge in water treatment.We employed N_(2)/low-temperature plasma technology to modify the surface of ...Enhancing the catalytic hydrolysis efficiency of microcystins(MCs)at ambient temperature has been a persistent challenge in water treatment.We employed N_(2)/low-temperature plasma technology to modify the surface of natural pyrites(NP),and the resulting nitrogenmodified pyrites(NPN)with a nanorod structure and new Fe-Nx sites are more efficient for the hydrolysis of microcystins-LR(MC-LR).Kinetic experiments revealed that NPN exhibited significantly higher hydrolysis activity(k_(obs)=0.1471 h^(-1))than NP(0.0914 h^(-1)).Liquid chromatography-mass spectrometry(LC/MS)for the intermediates produced by hydrolyzing MC-LR,in situ attenuated total reflectance Fourier transform infrared spectroscopy(in situ ATR-FTIR)and X-ray photoelectron spectroscopy(XPS)analysis unfolded that the Fe and N atoms of Fe-Nx sites on the surface act of NPN as Lewis acid and Bronsted basic respectively,selectively breaking amide bond on MC-LR molecule.This study demonstrates the effectiveness of plasma technology in modifying mineral materials to enhance their catalytic activity,providing a new method for eliminating MCs in practical water treatment.展开更多
Ammonia borane(AB)is a promising hydrogen storage medium widely used for hydrogen generation,but its slow hydrolysis kinetics limits its applications.Medium/high-entropy materials(M/HEMs)have emerged as efficient cata...Ammonia borane(AB)is a promising hydrogen storage medium widely used for hydrogen generation,but its slow hydrolysis kinetics limits its applications.Medium/high-entropy materials(M/HEMs)have emerged as efficient catalysts due to their complementary elemental and structural properties.We developed a deposition in-situ reduction(D-ISR)approach for the rapid synthesis of single-phase medium/high-entropy oxides(M/HEOs)at room temperature,along with establishing general criteria for M/HEOs synthesis based on component properties.Deposition facilitates the incorporation of active elements(Ti/Zr/V/Cr/Nb),which significantly enhance the enthalpy-driven force of the dynamic oxidation(DO)process via an“active element coordination”strategy,thereby overcoming low-temperature solid solubility limitations.Nine-component HEOs and large-scale experiments confirm the universality and mass-production potential of the D-ISR approach.CoCuNiTi-O/AC synthesized via this strategy exhibits pronounced crystal distortion and disorder(Co–O coordination number=10.2),enhancing the Co–O coordination environment and mitigating Ostwald ripening.This leads to high activity and significantly enhanced structural stability,achieving a turnover frequency of 236.6 min^(-1)for ammonia borane hydrolysis,15 times higher than Co-O/AC and surpassing the most non-noble catalysts.These observations highlight an efficient M/HEOs synthesis methodology that advances M/HEMs applications in nanoenergy.展开更多
Poly(lactic acid)(PLA),a bio-based polymer,is considered to be a sustainable alternative to conventional petroleum-based plastics.However,owing to its widespread use and relatively slow degradation rate in water,PLA s...Poly(lactic acid)(PLA),a bio-based polymer,is considered to be a sustainable alternative to conventional petroleum-based plastics.However,owing to its widespread use and relatively slow degradation rate in water,PLA still poses potential environmental pollution risks after being discarded.The efficient chemical recycling of PLA represents an attractive approach to addressing both resource reuse and environmental pollution challenges caused by its waste.Hydrolysis is the predominant method of industrial recycling.However,because PLA is insoluble in water,efficient heterogeneous hydrolysis requires high-temperature and high-pressure conditions.In this study,an efficient homogenous hydrolysis method capable of simultaneously dissolving PLA and calcium hydroxide(Ca(OH)_(2))was developed.Suitable solvents for this method were screened,and it was found that PLA hydrolysis using dioxane and 1,4,7,10,13-Pen-taoxacyclopentadecane as solvents achieved conversion rates of 93%and 90%,respectively,within 2 h at room temperature.Notably,the hydrolysis product,calcium lactate,precipitated as a solid from the solvent and therefore self-separated from the reaction solution.The solvent,acid/base conditions,water content,and depolymerization kinetics were investigated.Compared with previously reported hydrolysis methods,the enhanced efficiency observed in this study can be attributed to the concurrent solvation of PLA and Ca(OH)_(2),which maintains homogeneity throughout the reaction process.Additionally,this method facilitates closed-loop recycling of PLA and is compatible with the highly selective recovery of PLA from various types of PLA products.展开更多
Amorphous bimetallic borides,as a new generation of catalytic nanomaterials with modifiable electronic properties,are of great importance in the design of high-efficiency catalysts for NaBH_(4) hydrolysis.This study s...Amorphous bimetallic borides,as a new generation of catalytic nanomaterials with modifiable electronic properties,are of great importance in the design of high-efficiency catalysts for NaBH_(4) hydrolysis.This study synthesizes an amorphous Co_(3)B-Mo_(2)B_(5) catalyst using a self-sacrificial template strategy and NaBH_(4) reduction for both NaBH_(4) hydrolysis and the reduction of 4-nitrophenol.The catalyst delivers an impressive hydrogen generation rate of 7690.5 mL min^(-1) g^(-1) at 25℃,coupled with a rapid reaction rate of 0.701 min^(-1) in the reduction of 4-nitrophenol.The enhanced catalytic performance is attributed to the unique amorphous structure and the electron rearrangement between Co_(3)B and Mo_(2)B_(5).Experimental and theoretical analyses suggest electron transfer from Co_(3)B to the Mo_(2)B_(5),with the electron-deficient Co_(3)B site favoring BH_(4)^(-) adsorption,while the electron-rich Mo_(2)B_(5) site favoring H_(2)O adsorption,Furthermore,Co_(3)B-Mo_(2)B_(5) demonstrated potential for energy applications,delivering a power output of 0.3 V in a hydrogen-air fuel cell.展开更多
文摘In this work,we proposed a strategy for the hydrolysis of native corn starch after the treatment of corn starch in an ionic liquid aqueous solution,and it is an awfully“green”and simple means to obtain starch with low molecular weight and amorphous state.X-ray diffraction results revealed that the natural starch crystalline region was largely disrupted by ionic liquid owing to the broken intermolecular and intramolecular hydrogen bonds.After hydrolysis,the morphology of starch changed from particles of native corn starch into little pieces,and their molecular weight could be effectively regulated during the hydrolysis process,and also the hydrolyzed starch samples exhibited decreased thermal stability with the extension of hydrolysis time.This work would counsel as a powerful tool for the development of native starch in realistic applications.
基金financed jointly by the National Natural Science Foundation of China(42472127,42172086)the Yunnan Major Science and Technological Projects(202202AG050014)+2 种基金the Yunnan Major Project of Basic Research(202401BN070001-002)Yunnan Mineral Resources Prediction and Evaluation Engineering Research Center(2011)Innovation Team Program of Kunming University of Science and Technology,Yunnan Province。
文摘Recent studies have confirmed the critical and essential role of elemental hydrolysis in metallogenic processes,such as metal migration and precipitation.However,the kinetic processes,characteristics,and formation mechanisms of hydrolyzed precipitates require further comprehensive investigation.This paper is based on a systematic investigation of the hydrolysis mechanisms of Pb and Zn in various systems under ambient temperature and pressure,the storage conditions of the hydrolyzed precipitates,and the characterization of these precipitates.The results indicate that the hydrolysis behaviors of Pb and Zn exhibit significant differences across various systems.Within the monometallic regime,there is a pronounced disparity in the hydrolysis rates between Pb ions and Zn ions.Pb ions demonstrate a substantially higher degree of hydrolysis,a trend that persists over time and remains largely unaffected by the fluid retention or isolation"phenomenon in the surrounding environment.Both hydrolytic precipitation rates were observed to decrease in the mixed system,with Zn ions exhibiting less reduction than Pb ions.After hydrolysis,hydrolyzed precipitates can remain in the fluid environment for extended periods of time,which can lead to re-dissolution.Over time,this re-dissolution can increase,eventually leading to significant loss of hydrolyzed precipitates.The hydrolyzed precipitates obtained from the experiments primarily consisted of alkaline carbonates of Pb and Zn.Notably,the crystalline characteristics of the hydrolysis products of Pb and Zn ions exhibited significant differences across various experimental systems;however,the crystallographic characteristics of the primary hydrolysis products are essentially identical to those of their corresponding natural counterparts.Based on the findings from physical phase analysis and previous research,it is concluded that the hydrolysis process consists of three main stages:oxides/hydroxides,carbonates,and alkali carbonates.In the Pb-Zn-NaCl-H_(2)O system,the proportion of the basic carbonate products of Pb and Zn is 6:2.This research offers an in-depth analysis of the hydrolysis dynamics of lead and zinc under ambient temperature and pressure conditions.Furthermore,it characterizes the crystallization features of the hydrolyzed precipitates and reconstructs the three stages of the formation process.This study holds significant scientific value for understanding the metallogenic mechanisms of Pb and Zn.
文摘With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.
基金supported by the National Natural Science Foundation of China(21908135)Natural Science Foundation of Shanxi Datong University(2022K23)+1 种基金Graduate Research Innovation and Practice Innovation Projects of Shanxi Datong University(23CX31)Postgraduate Educational Reform and Research Program of Shanxi Datong University(23JG07)。
文摘Ammonia borane(AB)has received much attention as an environmentally friendly,non-toxic,room temperature stable hydrogen storage material with high hydrogen content of 19.6%.However,its hydrolysis for hydrogen production at room-temperature is kinetically slow and requires precious metal catalysts.In this work,it is found that the prepared Raney Ni W-r treated with high concentration of NaOH(6.25 mol/L)at 110℃exhibited excellent catalytic performance for AB hydrolysis at room temperature.The Raney Ni W-r can promote the AB complete hydrolysis within 60 s under basic condition at small sized trials,even higher than that of the 20%Pt/C catalyst.Its apparent activation energy at room temperature is only 26.6 kJ/mol and the turnover frequency(TOF)value is as high as 51.42 min-1.Owing to its high density and magnetic properties,the catalyst is very easy for magnetic separation.Furthermore,possible mechanism of the hydrolytic reaction of AB based on experimental results is proposed.As a well-established industrial catalyst,Raney Ni has been prepared on a large scale at low cost.This study provides a promising pathway for the large-scale preparation of low-cost and recyclable catalysts for AB hydrolysis.
基金financially supported by"Pioneer"and"Leading Goose"R&D Program of Zhejiang(No.2023C03130)the National Natural Science Foundation of China(No.22373029)+1 种基金Interdisciplinary Research Project of Hangzhou Normal University(No.2024JCXK02)Open Project Program of Key Laboratory of Yarn Materials Forming and Composite Processing Technology of Zhejiang Province(No.MTC2022-09)。
文摘An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights of the pristine PLLA(crystalline part),single stem,and single cluster were determined by gel permeation chromatography(GPC)according to their evolution during alkali hydrolysis.The maximum-folding-number(in a single cluster)and minimum-cluster-number(in one polymer chain)were obtained using these molecular weights.With the help of two numbers,the chain folding and traversing during the melt crystallization process(at 120℃)of PLLA can be described as follows.Statistically,in a single polymer chain,there are at least 2 clusters consisting of up to 6.5 stems in each of them,while the rest of the polymer chain contributes to amorphous regions.Our results provide a new strategy for the investigation and fundamental understanding of the melt crystallization of PLLA.
基金support from the National Natural Science Foundation of China(22222808,21978200,22208330)the Postdoctoral Fellowship Programof CPSF(GZC20241204)+1 种基金the China Postdoctoral Science Foundation-Tianjin Joint Support Program(2023T022TJ)the Haihe Laboratory of Sustainable Chemical Transformations for financial support.
文摘The efficient and cost-effective implementation of ammonia borane(AB)hydrolysis dehydrogenation for hydrogen storage is crucial.This study investigated the role of solid acid Amberlyst-15(A-15)for hydrogen evolution from AB hydrolysis.Notably,AB hydrogen evolution rate can reach 194.15 ml·min^(-1)at 30℃,with a low apparent activation energy of 8.20 kJ·mol^(-1).After five cycles of reuse,the reaction involving A-15 could keep a conversion rate of about 93%.The AB hydrolysis follows quasi first-order kinetics with respect to the AB concentration and quasi zero-order kinetics with respect to the A-15 mass.According to the characterization results of XRD,ATR-FTIR,and in-situ MS,the boric acid was the dominant hydrolyzate,while water as a hydrogen donor in this reaction.Furthermore,based on the reasoning that hydrogen bonds between A-15 and AB(aq)promotes the diffusion of AB,release of H2 and the cleavage of O-H bond of H2O,a possible mechanism was proposed.
基金financially supported by the National Natural Science Foundation of China(No.52301276)Zhejiang Provincial Natural Science Foundation of China(No.24E010001)+2 种基金Lishui Science and Technology Plan Project(No.2023GYX09)the support of the National Natural Science Foundation of China(52371229)Shanghai High-level Talent start funding
文摘The high hydrogen desorption density(19.6 wt%)of ammonia borane(AB)makes it one of the most promising chemical hydrogen storage materials.Developing cost-effective catalysts is the key for accelerating the hydrolysis of AB.Herein,we present a straightforward synthesis method for the Cu_(2)O decorated CoO catalyst derived from ZIF-67 precursors using carbothermal shock(~1 s)in air.The obtained results demonstrate that a small amount of Cu_(2)O doping into CoO synergistically enhances AB hydrolysis,resulting in an almost fivefold increase in turnover frequency(TOF=97 molH_(2)molCoO-1min-1at 298 K).Further studies indicated that the incorporation of Cu_(2)O alters the electronic distribution of the surface of catalysts,introducing more oxygen vacancies and increasing the pyridinic nitrogen content.The increased oxygen vacancies effectively enhanced the adsorption and activation ability of active sites for reactants(H_(2)O and AB),while the targeting effect of pyridinic nitrogen enhances the dispersion of the catalyst.Theoretical analysis reveals that CoO plays a key role in the dissociation of H_(2)O,while minor doping with Cu_(2)O substantially reduces the dissociation energy barrier of AB.This research provides a novel strategy for the design and efficient preparation of AB hydrolysis catalysts for efficient hydrogen production.
基金supported by the Key Research and Development Program of Hebei Province(No.21373702D)the Key Science and Technology Program of HBIS Group Co.,Ltd.(No.HG2021117)+1 种基金the National Natural Science Foundation of China(No.52370124)the National Key R&D Program of China(No.2023YFC3707003).
文摘About 70%of the flue gas in the iron-steel industry has achieved multi-pollutant ultra-low emissions in China until 2023,and then the blast furnace gas purification has become the control step and bottleneck.Our research group has designed and constructed the world’s first blast furnace gas desulfurization pilot plant with the scale of 2000 Nm^(3)/h in October 2021.The pilot plant is a two-step combined desulfurization device including catalytic hydrolysis of carbonyl sulfur(COS)and absorption-oxidation of H_(2)S,continuously running for 120 days.In the hydrolysis system,one reason for catalyst deactivation has been verified from the sulfur deposition.HCN in blast furnace gas can be hydrolyzed on the hydrolysis catalyst to produce the nitrogen deposition,which is one of the reasons for catalyst deactivation and has never been found in previous studies.The deposition forms of S and N elements are determined,S element forms elemental sulfur and sulfate,while N element forms-NH_(2)and NH_(4)^(+).In the absorption-oxidation system,the O_(2)loading and the residence time have been optimized to control the oxidation of HS^(−)to produce elemental sulfur instead of by-product S_(2)O_(3)^(2−).The balance and distribution of S and N elements have been calculated for thewholemulti-phase system,approximately 84.4%of the sulfur is converted to solid sulfur product,about 1.3%of the sulfur and 19.2%of N element are deposited on the hydrolysis catalyst.The pilot plant provides technical support formulti-pollutant control of blast furnace.
文摘Immobilization of alcalase on a ZIF-L(A@ZIF-L)support was explored for its potential application in producing hydrolysates of proteins extracted from microalgae.The immobilized enzyme was characterized using FTIR,XRD,SEM,and TGA,and the maximum adsorption capacity was found to be 672.1±5.5 mg g^(-1)at 40℃.Adsorption equilibrium data indicated that alcalase physically adsorbed onto the ZIF-L,with the isotherm well described by the Freundlich model.The adsorption kinetics aligned best with the pseudo-first order model,suggesting that both film and intraparticle diffusion were significant.The hydrolytic activity of the immobilized A@ZIF-L was initially tested using BSA as a substrate.A diffusion-reaction model was developed and numerically solved to describe the reaction,with results confirming the presence of mass transfer limitations in the early stages of hydrolysis.The stability of the immobilized enzyme was demonstrated by retaining over 90%of its initial activity after being stored at 4℃ for 70 days.Furthermore,the immobilized A@ZIF-L was used to hy-drolyze protein extracts derived from Scenedesmus sp.microalgae.The bioactivity of the resulting protein hy-drolysates was characterized,showing a total phenolic content of 29.1±0.6 mg GAE g^(-1)and a radical scavenging activity of 82.75±2.20%.These findings highlight the potential of Alcalase-based biocatalysts for applications in the food industry.
基金supported by the Fundamental Research Program of Shanxi Province(Nos.202203021211193 and 202203021211190)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Nos.2022L291 and 2022L274)+1 种基金the National Natural Science Foundations of China(Nos.51761032,51871125 and 52071227)the Key Scientific Research Project in Shanxi Province(No.202102050201003).
文摘The hydrolysis behavior of CaMg_(2)In_(0.1),CaMg_(2)In_(0.3),CaMg_(2)In_(0.5),and CaMg_(2)In_(0.7)ternary alloys in an MgCl_(2) solution following casting and hydrogenation were investigated.The hydrolysis mechanism of these alloys is elucidated through an analysis of microstructure,phase composition,and kinetics before and after hydrolysis.The nucleation-growth Avrami model is employed to accurately model the hydrolysis kinetics,revealing improved hydrolysis yields and reaction rates following hydrogenation.Notably,CaMg_(2)In_(0.1)has demonstrated exceptional hydrolysis characteristics,exhibiting a yield of 1140 mL/g,an initial hydrolysis rate of 113 mL/g·s,and an activation energy of 24.3±1.7 kJ·mol^(-1).The yield of H-CaMg_(2)In_(0.1)further escalates to 1800 mL/g with a rate of 221 mL/g·s,attributed to the formation of Ca_(4)Mg_(3)H_(14)and In phases subsequent to the hydrogenation of In_(2)Ca and Mg_(3)In phases in the alloy.These newly formed phases act as catalysts and actively participate in the hydrolysis process,providing active sites for hydrogen production,thus enhancing hydrolysis yields and kinetics.It is observed that with increasing In content,the order of hydrolysis performance of the alloy is as follows:CaMg_(2)In_(0.1)>CaMg_(2)In_(0.3)>CaMg_(2)In_(0.5)>CaMg_(2)In_(0.7),consistent with the trend after hydrogenation.These findings indicate that the addition of In significantly enhances the hydrolysis performance of CaMg_(2)alloys,offering a promising strategy for preparing magnesium-based alloys with high yields and favorable kinetic properties.
基金supported by the National Natural Science Foundation of China(Nos.22076098,22376118 and 21577078)the Outstanding Youth Project of the Natural Science Foundation of Hubei Province(2023AFA054)the 111 Project of China(No.D20015).
文摘Enhancing the catalytic hydrolysis efficiency of microcystins(MCs)at ambient temperature has been a persistent challenge in water treatment.We employed N_(2)/low-temperature plasma technology to modify the surface of natural pyrites(NP),and the resulting nitrogenmodified pyrites(NPN)with a nanorod structure and new Fe-Nx sites are more efficient for the hydrolysis of microcystins-LR(MC-LR).Kinetic experiments revealed that NPN exhibited significantly higher hydrolysis activity(k_(obs)=0.1471 h^(-1))than NP(0.0914 h^(-1)).Liquid chromatography-mass spectrometry(LC/MS)for the intermediates produced by hydrolyzing MC-LR,in situ attenuated total reflectance Fourier transform infrared spectroscopy(in situ ATR-FTIR)and X-ray photoelectron spectroscopy(XPS)analysis unfolded that the Fe and N atoms of Fe-Nx sites on the surface act of NPN as Lewis acid and Bronsted basic respectively,selectively breaking amide bond on MC-LR molecule.This study demonstrates the effectiveness of plasma technology in modifying mineral materials to enhance their catalytic activity,providing a new method for eliminating MCs in practical water treatment.
基金the financial support from the National Natural Science Foundation of China(52171223)the Guangxi Science and Technology Major Project(No.AA24206007)。
文摘Ammonia borane(AB)is a promising hydrogen storage medium widely used for hydrogen generation,but its slow hydrolysis kinetics limits its applications.Medium/high-entropy materials(M/HEMs)have emerged as efficient catalysts due to their complementary elemental and structural properties.We developed a deposition in-situ reduction(D-ISR)approach for the rapid synthesis of single-phase medium/high-entropy oxides(M/HEOs)at room temperature,along with establishing general criteria for M/HEOs synthesis based on component properties.Deposition facilitates the incorporation of active elements(Ti/Zr/V/Cr/Nb),which significantly enhance the enthalpy-driven force of the dynamic oxidation(DO)process via an“active element coordination”strategy,thereby overcoming low-temperature solid solubility limitations.Nine-component HEOs and large-scale experiments confirm the universality and mass-production potential of the D-ISR approach.CoCuNiTi-O/AC synthesized via this strategy exhibits pronounced crystal distortion and disorder(Co–O coordination number=10.2),enhancing the Co–O coordination environment and mitigating Ostwald ripening.This leads to high activity and significantly enhanced structural stability,achieving a turnover frequency of 236.6 min^(-1)for ammonia borane hydrolysis,15 times higher than Co-O/AC and surpassing the most non-noble catalysts.These observations highlight an efficient M/HEOs synthesis methodology that advances M/HEMs applications in nanoenergy.
基金financially supported by the National Key R&D Program of China(No.2021YFB3801901)the National Natural Science Foundation of China(No.22075188 and U19A2095)supported by State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology。
文摘Poly(lactic acid)(PLA),a bio-based polymer,is considered to be a sustainable alternative to conventional petroleum-based plastics.However,owing to its widespread use and relatively slow degradation rate in water,PLA still poses potential environmental pollution risks after being discarded.The efficient chemical recycling of PLA represents an attractive approach to addressing both resource reuse and environmental pollution challenges caused by its waste.Hydrolysis is the predominant method of industrial recycling.However,because PLA is insoluble in water,efficient heterogeneous hydrolysis requires high-temperature and high-pressure conditions.In this study,an efficient homogenous hydrolysis method capable of simultaneously dissolving PLA and calcium hydroxide(Ca(OH)_(2))was developed.Suitable solvents for this method were screened,and it was found that PLA hydrolysis using dioxane and 1,4,7,10,13-Pen-taoxacyclopentadecane as solvents achieved conversion rates of 93%and 90%,respectively,within 2 h at room temperature.Notably,the hydrolysis product,calcium lactate,precipitated as a solid from the solvent and therefore self-separated from the reaction solution.The solvent,acid/base conditions,water content,and depolymerization kinetics were investigated.Compared with previously reported hydrolysis methods,the enhanced efficiency observed in this study can be attributed to the concurrent solvation of PLA and Ca(OH)_(2),which maintains homogeneity throughout the reaction process.Additionally,this method facilitates closed-loop recycling of PLA and is compatible with the highly selective recovery of PLA from various types of PLA products.
基金supported by the National Natural Science Foundation of China(Nos.52363028,21965005)Natural Science Foundation of Guangxi(Nos.2021GXNSFAA076001,2018GXNSFAA294077)Guangxi Technology Base and Talent Subject(Nos.GUIKE AD23023004,GUIKE AD20297039)。
文摘Amorphous bimetallic borides,as a new generation of catalytic nanomaterials with modifiable electronic properties,are of great importance in the design of high-efficiency catalysts for NaBH_(4) hydrolysis.This study synthesizes an amorphous Co_(3)B-Mo_(2)B_(5) catalyst using a self-sacrificial template strategy and NaBH_(4) reduction for both NaBH_(4) hydrolysis and the reduction of 4-nitrophenol.The catalyst delivers an impressive hydrogen generation rate of 7690.5 mL min^(-1) g^(-1) at 25℃,coupled with a rapid reaction rate of 0.701 min^(-1) in the reduction of 4-nitrophenol.The enhanced catalytic performance is attributed to the unique amorphous structure and the electron rearrangement between Co_(3)B and Mo_(2)B_(5).Experimental and theoretical analyses suggest electron transfer from Co_(3)B to the Mo_(2)B_(5),with the electron-deficient Co_(3)B site favoring BH_(4)^(-) adsorption,while the electron-rich Mo_(2)B_(5) site favoring H_(2)O adsorption,Furthermore,Co_(3)B-Mo_(2)B_(5) demonstrated potential for energy applications,delivering a power output of 0.3 V in a hydrogen-air fuel cell.
