Photocatalytic disinfection is an eco-friendly strategy for countering bacterial pollution in aquatic environments.Numerous strategies have been devised to facilitate the generation of reactive oxygen species(ROS)with...Photocatalytic disinfection is an eco-friendly strategy for countering bacterial pollution in aquatic environments.Numerous strategies have been devised to facilitate the generation of reactive oxygen species(ROS)within photocatalysts,ultimately leading to the eradication of bacteria.However,the significance of the physical morphology of photocatalysts in the context of sterilization is frequently obscured,and the progress in the development of physical-chemical synergistic sterilization photocatalysts has been relatively limited.Herein,graphitic carbon nitride(g-C_(3)N_(4))is chemically protonated to expose more sharp edges.PL fluorescence and EIS results indicate that the protonation can accelerate photogenerated carrier separation and enhance ROS production.Meanwhile,the sharp edges on the protonated g-C_(3)N_(4)facilitate the physical disruption of cell walls for further promoting oxidative damage.Protonated C_(3)N_(4)demonstrated superior bactericidal performance than that of pristine g-C_(3)N_(4),effectively eliminating Escherichia coli within 40 minutes under irradiation.This work highlights the significance of incorporating physical and chemical synergies in photocatalyst design to enhance the disinfection efficiency of photocatalysis.展开更多
Rhodopsin is a seven-helical transmembrane protein with a retinal chromophore covalently bound to a conserved lysine in helix G via a retinal protonated Schiff base(RPSB).Microbial rhodopsins absorb light through chro...Rhodopsin is a seven-helical transmembrane protein with a retinal chromophore covalently bound to a conserved lysine in helix G via a retinal protonated Schiff base(RPSB).Microbial rhodopsins absorb light through chromophore and play a fundamental role in optogenetics.Numerous microbial rhodopsins have been discovered,contributing to diverse functions and colors.Solid-state NMR spectroscopy has been instrumental in elucidating the conformation of chromophores and the three-dimensional structure of microbial rhodopsins.This review focuses on the 15N chemical shift values of RPSB and summarizes recent progress in the field.We displayed the correlation between the 15N isotropic chemical shift values of RPSB and the maximum absorption wavelength of rhodopsin using solid-state NMR spectroscopy.展开更多
New layered perovskites, KSr2Nb3O10 and two new protonated niobates HSr2 Nb3O10·1.2H2O and HSr2Nb3O10,were synthesized by solid state reaction and ion-exchange reaction. These new compounds -were characterized by...New layered perovskites, KSr2Nb3O10 and two new protonated niobates HSr2 Nb3O10·1.2H2O and HSr2Nb3O10,were synthesized by solid state reaction and ion-exchange reaction. These new compounds -were characterized by EPMA, AAS, XRD, IR, DTA and so on. The structure may be described as treble perovskite sheets [Sr2Nb3O10]- interleaved with K+ ,H3O + or H+. These new compounds are new members of the Dion-Jacob-sonseries with n=3 for the general formula M[An-1 NbnO3n+1], and their indexed X-ray powder diffraction data were first reported in the paper.展开更多
Formation and dissociation mechanisms of C-C＋ base pairs in acidic and alkaline environments are investigated, employing ab initio quantum chemical calculations. Our calculations suggest that, in an acidic environmen...Formation and dissociation mechanisms of C-C＋ base pairs in acidic and alkaline environments are investigated, employing ab initio quantum chemical calculations. Our calculations suggest that, in an acidic environment, a cytosine monomer is first protonated and then dimerized with an unprotonated cytosine monomer to form a C-C＋ base pair; in an alkaline environment, a protonated cytosine dimer is first unprotonated and then dissociated into two cytosine monomers. In addition, the force for detaching a C-C＋ base pair was found to be inversely proportional to the distance between the two cytosine monomers. These results provide a microscopic mechanism to qualitatively explain the experimentally observed reversible formation and dissociation of i-motifs.展开更多
A modified method for preparation and purification of Schiff base and protonated Schiff base from 9-cis-retinal has been suggested. Reaction took place in chloroform phase and purification was conducted by using water...A modified method for preparation and purification of Schiff base and protonated Schiff base from 9-cis-retinal has been suggested. Reaction took place in chloroform phase and purification was conducted by using water to remove the excess solvent, base and acid.展开更多
Converting sustainable solar energy into hydrogen energy over semiconductor-based photocatalytic materials provides an alternative to fossil fuel consumption.However,efficient photocatalytic splitting of water to real...Converting sustainable solar energy into hydrogen energy over semiconductor-based photocatalytic materials provides an alternative to fossil fuel consumption.However,efficient photocatalytic splitting of water to realize carbon-free hydrogen production remains a challenge.Heterojunction photocatalysts with well-defined dimensionality and perfectly matched interfaces are promising for achieving highly efficient solar-to-hydrogen conversion.Herein,we report the fabrication of a novel type of protonated graphitic carbon nitride(PCN)/Ti3C2 MXene heterojunctions with strong interfacial interactions.As expected,the two-dimensional(2D)PCN/2D Ti3C2 MXene interface heterojunction achieves a highly improved hydrogen evolution rate(2181μmol∙g‒1)in comparison with bulk g-C3N4(393μmol∙g‒1)and protonated g-C3N4(816μmol∙g‒1).The charge-regulated surfaces of PCN and the accelerated charge transport at the face-to-face 2D/2D Schottky heterojunction interface are the major contributors to the excellent hydrogen evolution performance of the composite photocatalyst.展开更多
Infrared multiple photon dissociation （IRMPD） spectroscopic and theoretical studies of protonated homodimers of amino acids generated by electrospray ionization in the gas phase have been reviewed. Results show that...Infrared multiple photon dissociation （IRMPD） spectroscopic and theoretical studies of protonated homodimers of amino acids generated by electrospray ionization in the gas phase have been reviewed. Results show that proton affinity （PA） may be applied as a probe to predict their structural type： salt- bridged or charge-solvated. Proline can be viewed as a reference. For an amino acid with a PA value higher than that of proline, the most stable conformation of its protonated homodimer tends to prefer salt- bridged conformation; otherwise, charge-solvated conformation is expected to be the most stable. However, side chain effects may cause the inaccuracy in structural determination due to the strong interactions with the charge, which makes the charge-solvated structure more stable even for species with high PA values. Temperature effect on distribution of different isomers is also very important. In lots of cases, the coexistence of multiple isomers is general, which makes the explanation of an overall IRMPD spectrum difficult. So a statistical view on the distribution of optimized isomers is very helpful.展开更多
The low energy collisioninduced dissociation, linked scan techniques and isotopic labeling experiment were used to investigate the unimolecular fragmentation of protonated N-hydroxyphthalimide under electron impact a...The low energy collisioninduced dissociation, linked scan techniques and isotopic labeling experiment were used to investigate the unimolecular fragmentation of protonated N-hydroxyphthalimide under electron impact and chemical ionization conditions. It was found that this compound shows an unusual reactivity towards protonation. Two possible sites of protonation have been proposed to explain the corresponding fragmentation processes, one is that the protonation takes place on the oxygen atom of hydroxyl group, resulting in the loss of water and the other is the formation of an intermediary protonbound complex in the fragmentation process, giving rise to the fragment ions of m/z 133 and m/z 135. The results show both cases are coexistence in the fragmentations of protonated N-hydroxyphthalimide, and the unimolecular fragmentation pathways are available.展开更多
Density functional calculations are used to determine structural and electronic properties of P4,P4O6,P4O10,P20O30 and P20O50 clusters and their protonated derivatives.These oxygen-rich phosphorus oxides are predicted...Density functional calculations are used to determine structural and electronic properties of P4,P4O6,P4O10,P20O30 and P20O50 clusters and their protonated derivatives.These oxygen-rich phosphorus oxides are predicted to have relatively high stabilities with respect to their components P4 and O2,and their unsaturated P and end-on O atoms as the proton acceptor can accommodate multiple protons to generate highly positively charged cationic clusters,such as P20O30H1010＋.Calculations indicate that P4O6 and P20O30 have higher reactivity toward the proton capture than the P4,P4O10 and P20O50 clusters,and the most stable protonated clusters among these different series of cationic clusters are P4H2……2＋,P4O6H2^2＋,P4O10H3^3＋,P20O30H4^4＋ and P20O50H4^4＋,respectively.The cage skeleton of the phosphorus oxide clusters shows high stability for the consecutive protonation,and the unsymmetrical stretching of the skeletal P-O bond and the wagging mode of P-H coupled with the P-O bond stretching have strong adsorptions.These computational findings are useful for further experimental and theoretical studies of novel phosphorus oxide clusters and their highly positively charged derivatives.展开更多
Covalent organic frameworks(COFs)are emerging as promising photocatalysts owing to their tailorable structures,exceptional crystallinity,and robustness.However,the photocatalytic performance of COFs is limited by fast...Covalent organic frameworks(COFs)are emerging as promising photocatalysts owing to their tailorable structures,exceptional crystallinity,and robustness.However,the photocatalytic performance of COFs is limited by fast charge recombination and inefficient charge migration.Herein,a novel post-synthetic partial protonation strategy is proposed to construct COFs with asymmetric unprotonated/protonated homojunctions,which endow them with an enlarged molecular dipole moment,thereby generating a strong built-in electric field that significantly enhances the charge separation and transport efficiencies in COFs.In addition,the protonation process extends the light absorption range and improves the hydrophilicity of COFs.The photocatalytic hydrogen evolution rate of the partially protonated TPE-COF and ETTBA-COF is enhanced by 88-and 175-fold relative to their pristine counterparts,4.3 and 2.48 times those of fully protonated counterparts,respectively.Our results clearly demonstrate the pivotal role of the asymmetric unprotonated/protonated homojunctions within COFs in the photocatalytic hydrogen evolution.This post-synthetic partial protonation strategy provides a novel paradigm for establishing internal electric fields within COFs.展开更多
In this work, we demonstrated the successful construction of metal-free zero- dimensional/two-dimensional carbon nanodot （CND）-hybridized protonatedg=C3N4 （pCN） （CND/pCN） heterojunction photocatalysts b; means o...In this work, we demonstrated the successful construction of metal-free zero- dimensional/two-dimensional carbon nanodot （CND）-hybridized protonatedg=C3N4 （pCN） （CND/pCN） heterojunction photocatalysts b; means of electrostatic attraction. We experimentally found that CNDs with an average diameter of 4.4 nm were uniformly distributed on the surface of pCN using electron microscopy analysis. The CND/pCN-3 sample with a CND content of 3 wt.% showed thehighest catalytic activity in the CO2 photoreduction process under visible and simulated solar light. This process results in the evolution of CH4 and CO. Thetotal amounts of CH4 and CO generated by the CND/pCN-3 photocatalyst after 10 h of visible-light activity were found to be 29.23 and 58.82 molgcatalyst-1, respectively. These values were 3.6 and 2.28 times higher, respectively, than thearn＊ounts generated when using pCN alone. The corresponding apparent quantum efficiency （AQE） was calculated to be 0.076%. Furthermore, the CND/pCN-3 sample demonstrated high stability and durability after four consecutive photoreaction cycles, with no significant decrease in the catalytic activity.展开更多
Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SO...Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SOECs with Zr-rich electrolyte,called Zr-rich side P-SOECs,possess high thermodynamically stability under high steam concentrations but the large reaction resistances and the current leakage,thus the inferior performances.In this study,an efficient functional interlayer Ba_(0.95)La_(0.05)Fe_(0.8)Zn_(0.2)O_(3-δ)(BLFZ)in-between the anode and the electrolyte is developed.The electrochemical performances of P-SOECs are greatly enhanced because the BLFZ can greatly increase the interface contact,boost anode reaction kinetics,and increase proton injection into electrolyte.As a result,the P-SOEC yields high current density of 0.83 A cm^(-2) at 600℃ in 1.3 Vamong all the reported Zr-rich side cells.This work not only offers an efficient functional interlayer for P-SOECs but also holds the potential to achieve P-SOECs with high performances and long-term stability.展开更多
Understanding the proton dynamic behavior in inorganic materials has long been a topic of intense fascination[1],especially in the field of electrochemical energy storage[2].One of the examples is the research of prot...Understanding the proton dynamic behavior in inorganic materials has long been a topic of intense fascination[1],especially in the field of electrochemical energy storage[2].One of the examples is the research of proton transport in transition metal oxides,which dates back to 1971[3]when RuO_(2) was discovered to be capable of storing protons via reversible redox reactions[4].In aqueous electrolytes,the thin film RuO_(2) electrode exhibits a surface pseudocapacitive behavior[5],which could be modified by the structural water in its hydrated form due to the facile Grotthuss hopping mode of protons along the established hydrogen bonds inside the bulk phase[6].Soon later,Goodenough et al.reported the capacitor-like behavior of amorphous MnO_(2)·xH_(2)O electrode in an aqueous KCl electrolyte[7],and further studies on the hydrated MnO_(2) electrodes prepared by sol-gel processes have soon discovered that the intercalation of protons from aqueous electrolytes plays an indispensable role in the charge storage mechanism[8].In recent years,the research interest on rechargeable aqueous batteries has fueled the renaissance of mechanistic study of proton transport in transition metal oxides[9],which can operate as cathodes or anodes via a topotactic insertion mechanism similar to that in Li-ion batteries[10].However,due to the challenges for experimental detection of local chemical environments of the inserted protons,a comprehensive understanding of proton dynamic behavior in these electrodes remains largely lacking.展开更多
Proton-conducting materials have attracted considerable interest because of their extensive application in energy storage and conversion devices.Among them,metal-organic frameworks(MOFs)present tremendous development ...Proton-conducting materials have attracted considerable interest because of their extensive application in energy storage and conversion devices.Among them,metal-organic frameworks(MOFs)present tremendous development potential and possibilities for constructing novel advanced proton conductors due to their special advantages in crystallinity,designability,and porosity.In particular,several special design strategies for the structure of MOFs have opened new doors for the advancement of MOF proton conductors,such as charged network construction,ligand functionalization,metal-center manipulation,defective engineering,vip molecule incorporation,and pore-space manipulation.With the implementation of these strategies,proton-conducting MOFs have developed significantly and profoundly within the last decade.Therefore,in this review,we critically discuss and analyze the fundamental principles,design strategies,and implementation methods targeted at improving the proton conductivity of MOFs through representative examples.Besides,the structural features,the proton conduction mechanism and the behavior of MOFs are discussed thoroughly and meticulously.Future endeavors are also proposed to address the challenges of proton-conducting MOFs in practical research.We sincerely expect that this review will bring guidance and inspiration for the design of proton-conducting MOFs and further motivate the research enthusiasm for novel proton-conducting materials.展开更多
This article aims to deepen the understanding of the role of Helicobacter pylori(H.pylori)infection in the development of cholelithiasis,initiated by the article by Yao et al,who investigated the potential link betwee...This article aims to deepen the understanding of the role of Helicobacter pylori(H.pylori)infection in the development of cholelithiasis,initiated by the article by Yao et al,who investigated the potential link between H.pylori infection and the development of cholelithiasis through a multicenter retrospective study on an Asian population of over 70000 participants.They also performed a compre-hensive analysis of previously published studies on H.pylori and cholelithiasis,finding a positive association therein[odds ratio(OR)=1.103,P=0.049].Patients positive for H.pylori also had lower levels of total and direct bilirubin,but higher levels of total cholesterol and low-density lipoprotein cholesterol compared to uninfected patients(P<0.05).Cohort studies have confirmed that H.pylori is a risk factor for cholelithiasis(P<0.0001),and aggregate analyses of case-control and cross-sectional studies have shown a positive association between H.pylori and cholelithiasis in Asia(OR=1.599,P=0.034),but not in Europe(OR=1.277,P=0.246).Moreover,H.pylori appears to be related to a higher ratio of choledocho-lithiasis/cholecystolithiasis(OR=3.321,P=0.033).The authors conclude that H.pylori infection is positively correlated with cholelithiasis,particularly with the choledocholithiasis phenotype,especially in Asia,and it is potentially related to bilirubin and cholesterol metabolism.展开更多
Developing low-cost and high-performance nanofiber-based polyelectrolyte membranes for fuel cell applications is a promising solution to energy depletion.Due to the high specific surface area and one-dimensional longr...Developing low-cost and high-performance nanofiber-based polyelectrolyte membranes for fuel cell applications is a promising solution to energy depletion.Due to the high specific surface area and one-dimensional longrange continuous structure of the nanofiber,ion-charged groups can be induced to form long-range continuous ion transfer channels in the nanofiber composite membrane,significantly increasing the ion conductivity of the membrane.This review stands apart from previous endeavors by offering a comprehensive overview of the strategies employed over the past decade in utilizing both electrospun and natural nanofibers as key components of proton exchange membranes and anion exchange membranes for fuel cells.Electrospun nanofibers are categorized based on their material properties into two primary groups:(1)ionomer nanofibers,inherently endowed with the ability to conduct H+(such as perfluorosulfonic acid or sulfonated poly(ether ether ketone))or OH-(e.g.,FAA-3),and(2)nonionic polymer nanofibers,comprising inert polymers like polyvinylidene difluoride,polytetrafluoroethylene,and polyacrylonitrile.Notably,the latter often necessitates surface modifications to impart ion transport channels,given their inherent proton inertness.Furthermore,this review delves into the recent progress made with three natural nanofibers derived from biodegradable cellulose—cellulose nanocrystals,cellulose nanofibers,and bacterial nanofibers—as crucial elements in polyelectrolyte membranes.The effect of the physical structure of such nanofibers on polyelectrolyte membrane properties is also briefly discussed.Lastly,the review emphasizes the challenges and outlines potential solutions for future research in the field of nanofiber-based polyelectrolyte membranes,aiming to propel the development of high-performance polymer electrolyte fuel cells.展开更多
Hydrogen energy from electrocatalysis driven by sustainable energy has emerged as a solution against the background of carbon neutrality.Proton exchange membrane(PEM)-based electrocatalytic systems represent a promisi...Hydrogen energy from electrocatalysis driven by sustainable energy has emerged as a solution against the background of carbon neutrality.Proton exchange membrane(PEM)-based electrocatalytic systems represent a promising technology for hydrogen production,which is equipped to combine efficiently with intermittent electricity from renewable energy sources.In this review,PEM-based electrocatalytic systems for H2 production are summarized systematically from low to high operating temperature systems.When the operating temperature is below 130℃,the representative device is a PEM water electrolyzer;its core components and respective functions,research status,and design strategies of key materials especially in electrocatalysts are presented and discussed.However,strong acidity,highly oxidative operating conditions,and the sluggish kinetics of the anode reaction of PEM water electrolyzers have limited their further development and shifted our attention to higher operating temperature PEM systems.Increasing the temperature of PEM-based electrocatalytic systems can cause an increase in current density,accelerate reaction kinetics and gas transport and reduce the ohmic value,activation losses,ΔGH*,and power consumption.Moreover,further increasing the operating temperature(120-300℃)of PEM-based devices endows various hydrogen carriers(e.g.,methanol,ethanol,and ammonia)with electrolysis,offering a new opportunity to produce hydrogen using PEM-based electrocatalytic systems.Finally,several future directions and prospects for developing PEM-based electrocatalytic systems for H_(2) production are proposed through devoting more efforts to the key components of devices and reduction of costs.展开更多
The transition of hydrogen sourcing from carbon-intensive to water-based methodologies is underway,with renewable energy-powered proton exchange membrane water electrolysis(PEMWE)emerging as the preeminent pathway for...The transition of hydrogen sourcing from carbon-intensive to water-based methodologies is underway,with renewable energy-powered proton exchange membrane water electrolysis(PEMWE)emerging as the preeminent pathway for hydrogen production.Despite remarkable advancements in this field,confronting the sluggish electrochemical kinetics and inherent high-energy consumption arising from deteriorated mass transport within PEMWE systems remains a formidable obstacle.This impediment stems primarily from the hindered protons mass transfer and the untimely hydrogen bubbles detachment.To address these challenges,we harness the inherent variability of electrical energy and introduce an innovative pulsed dynamic water electrolysis system.Compared to constant voltage electrolysis(hydrogen production rate:51.6 m L h^(-1),energy consumption:5.37 kWh Nm-^(3)H_(2)),this strategy(hydrogen production rate:66 m L h^(-1),energy consumption:3.83 kWh Nm-^(3)H_(2))increases the hydrogen production rate by approximately 27%and reduces the energy consumption by about 28%.Furthermore,we demonstrate the practicality of this system by integrating it with an off-grid photovoltaic(PV)system designed for outdoor operation,successfully driving a hydrogen production current of up to 500 mA under an average voltage of approximately 2 V.The combined results of in-situ characterization and finite element analysis reveal the performance enhancement mechanism:pulsed dynamic electrolysis(PDE)dramatically accelerates the enrichment of protons at the electrode/solution interface and facilitates the release of bubbles on the electrode surface.As such,PDE-enhanced PEMWE represents a synergistic advancement,concurrently enhancing both the hydrogen generation reaction and associated transport processes.This promising technology not only redefines the landscape of electrolysis-based hydrogen production but also holds immense potential for broadening its application across a diverse spectrum of electrocatalytic endeavors.展开更多
This work demonstrates experimentally the close relation between return currents from relativistic laser-driven target polarization and the quality of the relativistic laser–plasma interaction for laser-driven second...This work demonstrates experimentally the close relation between return currents from relativistic laser-driven target polarization and the quality of the relativistic laser–plasma interaction for laser-driven secondary sources,taking as an example ion acceleration by target normal sheath acceleration.The Pearson linear correlation of maximum return current amplitude and proton spectrum cutoff energy is found to be in the range from~0.70 to 0.94.kA-scale return currents rise in all interaction schemes where targets of any kind are charged by escaping laser-accelerated relativistic electrons.Their precise measurement is demonstrated using an inductive scheme that allows operation at high repetition rates.Thus,return currents can be used as a metrological online tool for the optimization of many laser-driven secondary sources and for diagnosing their stability.In particular,in two parametric studies of laser-driven ion acceleration,we carry out a noninvasive online measurement of return currents in a tape target system irradiated by the 1 PW VEGA-3 laser at Centro de Láseres Pulsados:first the size of the irradiated area is varied at best compression of the laser pulse;second,the pulse duration is varied by means of induced group delay dispersion at best focus.This work paves the way to the development of feedback systems that operate at the high repetition rates of PW-class lasers.展开更多
To develop proton-conducting materials with high hydrothermal and acid-base stability and to elucidate the proton-transport mechanism through visualized structural analysis,two new lanthanum phosphite-oxalates with 3D...To develop proton-conducting materials with high hydrothermal and acid-base stability and to elucidate the proton-transport mechanism through visualized structural analysis,two new lanthanum phosphite-oxalates with 3D frameworks,designated as[La(HPO_(3))(C_(2)O_(4))0.5(H_(2)O)_(2)](La‑1)and(C_(6)H_(16)N_(2))(H_(3)O)[La_(2)(H_(2)PO_(3))_(3)(C_(2)O_(4))_(3)(H_(2)O)](La‑2)(C_(6)H_(14)N_(2)=cis-2,6-dimethylpiperazine),were prepared by hydrothermal and solvothermal conduction,respectively.La‑1 was constructed with lanthanum phosphite 2D layers and C_(2)O_(4)^(2-)groups,whereas La‑2 was constructed with lanthanum oxalate 2D layers and H_(2)PO^(3-)groups.Alternating current(AC)impedance spectra indicate that the pro-ton conductivities of both compounds could reach 10^(-4)S·cm^(-1)and remain highly durable at 75℃and 98%of rela-tive humidity(RH).Due to the abundance of H-bonds in La‑2,theσof La‑2 was higher than that of La‑1.La‑1 exhibited excellent water and pH stability.CCDC:2439965,La‑1;443776,La‑2.展开更多
基金supported by the National Natural Science Foundation of China(No.2021YFC3200603)the Special Research Assistant Program,Chinese Academy of Sciences.
文摘Photocatalytic disinfection is an eco-friendly strategy for countering bacterial pollution in aquatic environments.Numerous strategies have been devised to facilitate the generation of reactive oxygen species(ROS)within photocatalysts,ultimately leading to the eradication of bacteria.However,the significance of the physical morphology of photocatalysts in the context of sterilization is frequently obscured,and the progress in the development of physical-chemical synergistic sterilization photocatalysts has been relatively limited.Herein,graphitic carbon nitride(g-C_(3)N_(4))is chemically protonated to expose more sharp edges.PL fluorescence and EIS results indicate that the protonation can accelerate photogenerated carrier separation and enhance ROS production.Meanwhile,the sharp edges on the protonated g-C_(3)N_(4)facilitate the physical disruption of cell walls for further promoting oxidative damage.Protonated C_(3)N_(4)demonstrated superior bactericidal performance than that of pristine g-C_(3)N_(4),effectively eliminating Escherichia coli within 40 minutes under irradiation.This work highlights the significance of incorporating physical and chemical synergies in photocatalyst design to enhance the disinfection efficiency of photocatalysis.
基金supported in part by JSPS KAKENHI Grant Numbers in Japan(JP21H05229 to I.K.)JST CREST(JPMJCR21B2)The authors also thank Nobuko Yamaguchi for the financial support.
文摘Rhodopsin is a seven-helical transmembrane protein with a retinal chromophore covalently bound to a conserved lysine in helix G via a retinal protonated Schiff base(RPSB).Microbial rhodopsins absorb light through chromophore and play a fundamental role in optogenetics.Numerous microbial rhodopsins have been discovered,contributing to diverse functions and colors.Solid-state NMR spectroscopy has been instrumental in elucidating the conformation of chromophores and the three-dimensional structure of microbial rhodopsins.This review focuses on the 15N chemical shift values of RPSB and summarizes recent progress in the field.We displayed the correlation between the 15N isotropic chemical shift values of RPSB and the maximum absorption wavelength of rhodopsin using solid-state NMR spectroscopy.
基金Funded by Natural Science Foundation of China (No. 50002007), Major Program of Chinese Education Ministry and Open Foundation of State Key Lab. of Advanced Tech. for Materials Syn-thesis and Processing.
文摘New layered perovskites, KSr2Nb3O10 and two new protonated niobates HSr2 Nb3O10·1.2H2O and HSr2Nb3O10,were synthesized by solid state reaction and ion-exchange reaction. These new compounds -were characterized by EPMA, AAS, XRD, IR, DTA and so on. The structure may be described as treble perovskite sheets [Sr2Nb3O10]- interleaved with K+ ,H3O + or H+. These new compounds are new members of the Dion-Jacob-sonseries with n=3 for the general formula M[An-1 NbnO3n+1], and their indexed X-ray powder diffraction data were first reported in the paper.
基金Project supported by the National Basic Research Program of China (973 Program,Grant No.2013CB932804)the National Natural Science Foundation of China (Grant Nos.91227115 and 11121403)the Hundred Talent Program of the Chinese Academy of Sciences (CAS)
文摘Formation and dissociation mechanisms of C-C＋ base pairs in acidic and alkaline environments are investigated, employing ab initio quantum chemical calculations. Our calculations suggest that, in an acidic environment, a cytosine monomer is first protonated and then dimerized with an unprotonated cytosine monomer to form a C-C＋ base pair; in an alkaline environment, a protonated cytosine dimer is first unprotonated and then dissociated into two cytosine monomers. In addition, the force for detaching a C-C＋ base pair was found to be inversely proportional to the distance between the two cytosine monomers. These results provide a microscopic mechanism to qualitatively explain the experimentally observed reversible formation and dissociation of i-motifs.
文摘A modified method for preparation and purification of Schiff base and protonated Schiff base from 9-cis-retinal has been suggested. Reaction took place in chloroform phase and purification was conducted by using water to remove the excess solvent, base and acid.
文摘Converting sustainable solar energy into hydrogen energy over semiconductor-based photocatalytic materials provides an alternative to fossil fuel consumption.However,efficient photocatalytic splitting of water to realize carbon-free hydrogen production remains a challenge.Heterojunction photocatalysts with well-defined dimensionality and perfectly matched interfaces are promising for achieving highly efficient solar-to-hydrogen conversion.Herein,we report the fabrication of a novel type of protonated graphitic carbon nitride(PCN)/Ti3C2 MXene heterojunctions with strong interfacial interactions.As expected,the two-dimensional(2D)PCN/2D Ti3C2 MXene interface heterojunction achieves a highly improved hydrogen evolution rate(2181μmol∙g‒1)in comparison with bulk g-C3N4(393μmol∙g‒1)and protonated g-C3N4(816μmol∙g‒1).The charge-regulated surfaces of PCN and the accelerated charge transport at the face-to-face 2D/2D Schottky heterojunction interface are the major contributors to the excellent hydrogen evolution performance of the composite photocatalyst.
基金supported by the National Natural Science Foundation of China(Nos.21475065,21627801 and 11704280)
文摘Infrared multiple photon dissociation （IRMPD） spectroscopic and theoretical studies of protonated homodimers of amino acids generated by electrospray ionization in the gas phase have been reviewed. Results show that proton affinity （PA） may be applied as a probe to predict their structural type： salt- bridged or charge-solvated. Proline can be viewed as a reference. For an amino acid with a PA value higher than that of proline, the most stable conformation of its protonated homodimer tends to prefer salt- bridged conformation; otherwise, charge-solvated conformation is expected to be the most stable. However, side chain effects may cause the inaccuracy in structural determination due to the strong interactions with the charge, which makes the charge-solvated structure more stable even for species with high PA values. Temperature effect on distribution of different isomers is also very important. In lots of cases, the coexistence of multiple isomers is general, which makes the explanation of an overall IRMPD spectrum difficult. So a statistical view on the distribution of optimized isomers is very helpful.
文摘The low energy collisioninduced dissociation, linked scan techniques and isotopic labeling experiment were used to investigate the unimolecular fragmentation of protonated N-hydroxyphthalimide under electron impact and chemical ionization conditions. It was found that this compound shows an unusual reactivity towards protonation. Two possible sites of protonation have been proposed to explain the corresponding fragmentation processes, one is that the protonation takes place on the oxygen atom of hydroxyl group, resulting in the loss of water and the other is the formation of an intermediary protonbound complex in the fragmentation process, giving rise to the fragment ions of m/z 133 and m/z 135. The results show both cases are coexistence in the fragmentations of protonated N-hydroxyphthalimide, and the unimolecular fragmentation pathways are available.
基金Supported by the National Natural Science Foundation of China (21133007 and 20873105)the Ministry of Science and Technology (2011CB808504 and 2012CB214902)
文摘Density functional calculations are used to determine structural and electronic properties of P4,P4O6,P4O10,P20O30 and P20O50 clusters and their protonated derivatives.These oxygen-rich phosphorus oxides are predicted to have relatively high stabilities with respect to their components P4 and O2,and their unsaturated P and end-on O atoms as the proton acceptor can accommodate multiple protons to generate highly positively charged cationic clusters,such as P20O30H1010＋.Calculations indicate that P4O6 and P20O30 have higher reactivity toward the proton capture than the P4,P4O10 and P20O50 clusters,and the most stable protonated clusters among these different series of cationic clusters are P4H2……2＋,P4O6H2^2＋,P4O10H3^3＋,P20O30H4^4＋ and P20O50H4^4＋,respectively.The cage skeleton of the phosphorus oxide clusters shows high stability for the consecutive protonation,and the unsymmetrical stretching of the skeletal P-O bond and the wagging mode of P-H coupled with the P-O bond stretching have strong adsorptions.These computational findings are useful for further experimental and theoretical studies of novel phosphorus oxide clusters and their highly positively charged derivatives.
基金supported by the Science and Technology Project of Jiangsu Province(BZ2022056,BK20210356)the National Natural Science Foundation of China(22205109,21975128)the Fundamental Research Funds for the Central Universities(30922010812)。
文摘Covalent organic frameworks(COFs)are emerging as promising photocatalysts owing to their tailorable structures,exceptional crystallinity,and robustness.However,the photocatalytic performance of COFs is limited by fast charge recombination and inefficient charge migration.Herein,a novel post-synthetic partial protonation strategy is proposed to construct COFs with asymmetric unprotonated/protonated homojunctions,which endow them with an enlarged molecular dipole moment,thereby generating a strong built-in electric field that significantly enhances the charge separation and transport efficiencies in COFs.In addition,the protonation process extends the light absorption range and improves the hydrophilicity of COFs.The photocatalytic hydrogen evolution rate of the partially protonated TPE-COF and ETTBA-COF is enhanced by 88-and 175-fold relative to their pristine counterparts,4.3 and 2.48 times those of fully protonated counterparts,respectively.Our results clearly demonstrate the pivotal role of the asymmetric unprotonated/protonated homojunctions within COFs in the photocatalytic hydrogen evolution.This post-synthetic partial protonation strategy provides a novel paradigm for establishing internal electric fields within COFs.
文摘In this work, we demonstrated the successful construction of metal-free zero- dimensional/two-dimensional carbon nanodot （CND）-hybridized protonatedg=C3N4 （pCN） （CND/pCN） heterojunction photocatalysts b; means of electrostatic attraction. We experimentally found that CNDs with an average diameter of 4.4 nm were uniformly distributed on the surface of pCN using electron microscopy analysis. The CND/pCN-3 sample with a CND content of 3 wt.% showed thehighest catalytic activity in the CO2 photoreduction process under visible and simulated solar light. This process results in the evolution of CH4 and CO. Thetotal amounts of CH4 and CO generated by the CND/pCN-3 photocatalyst after 10 h of visible-light activity were found to be 29.23 and 58.82 molgcatalyst-1, respectively. These values were 3.6 and 2.28 times higher, respectively, than thearn＊ounts generated when using pCN alone. The corresponding apparent quantum efficiency （AQE） was calculated to be 0.076%. Furthermore, the CND/pCN-3 sample demonstrated high stability and durability after four consecutive photoreaction cycles, with no significant decrease in the catalytic activity.
基金financial support from the JSPS KAKENHI Grant-in-Aid for Scientific Research(B),No.21H02035KAKENHI Grant-in-Aid for Challenging Research(Exploratory),No.21K19017+2 种基金KAKENHI Grant-in-Aid for Transformative Research Areas(B),No.21H05100National Natural Science Foundation of China,No.22409033 and No.22409035Basic and Applied Basic Research Foundation of Guangdong Province,No.2022A1515110470.
文摘Protonic solid oxide electrolysis cells(P-SOECs)are a promising technology for water electrolysis to produce green hydrogen.However,there are still challenges related key materials and anode/electrolyte interface.P-SOECs with Zr-rich electrolyte,called Zr-rich side P-SOECs,possess high thermodynamically stability under high steam concentrations but the large reaction resistances and the current leakage,thus the inferior performances.In this study,an efficient functional interlayer Ba_(0.95)La_(0.05)Fe_(0.8)Zn_(0.2)O_(3-δ)(BLFZ)in-between the anode and the electrolyte is developed.The electrochemical performances of P-SOECs are greatly enhanced because the BLFZ can greatly increase the interface contact,boost anode reaction kinetics,and increase proton injection into electrolyte.As a result,the P-SOEC yields high current density of 0.83 A cm^(-2) at 600℃ in 1.3 Vamong all the reported Zr-rich side cells.This work not only offers an efficient functional interlayer for P-SOECs but also holds the potential to achieve P-SOECs with high performances and long-term stability.
基金financial support from the National Natural Science Foundation of China(22109003)the Basic and Applied Basic Research Foundation of Guangdong Province(2023A1515011391)+1 种基金Soft Science Research Project of Guangdong Province(No.2017B030301013)the Major Science and Technology Infrastructure Project of Material Genome Big-science Facilities Platform supported by Municipal Development and Reform Commission of Shenzhen.
文摘Understanding the proton dynamic behavior in inorganic materials has long been a topic of intense fascination[1],especially in the field of electrochemical energy storage[2].One of the examples is the research of proton transport in transition metal oxides,which dates back to 1971[3]when RuO_(2) was discovered to be capable of storing protons via reversible redox reactions[4].In aqueous electrolytes,the thin film RuO_(2) electrode exhibits a surface pseudocapacitive behavior[5],which could be modified by the structural water in its hydrated form due to the facile Grotthuss hopping mode of protons along the established hydrogen bonds inside the bulk phase[6].Soon later,Goodenough et al.reported the capacitor-like behavior of amorphous MnO_(2)·xH_(2)O electrode in an aqueous KCl electrolyte[7],and further studies on the hydrated MnO_(2) electrodes prepared by sol-gel processes have soon discovered that the intercalation of protons from aqueous electrolytes plays an indispensable role in the charge storage mechanism[8].In recent years,the research interest on rechargeable aqueous batteries has fueled the renaissance of mechanistic study of proton transport in transition metal oxides[9],which can operate as cathodes or anodes via a topotactic insertion mechanism similar to that in Li-ion batteries[10].However,due to the challenges for experimental detection of local chemical environments of the inserted protons,a comprehensive understanding of proton dynamic behavior in these electrodes remains largely lacking.
基金supported by the China Scholarship Council(No.202408120105)National Natural Science Foundation of China(32301530)+5 种基金Young Elite Scientist Sponsorship Program by CAST(No.YESS20230242)Tianjin Excellent Special Commissioner for Agricultural Science and Technology Project(23ZYCGSN00580)Natural Science Foundation of Tianjin(23JCZDJC00630)China Postdoctoral Science Foundation(2023M740563)State Key Laboratory of Pulp and Paper Engineering(202412,202413)the Central Publicinterest Scientific Institution Basa Research Fund(No.Y2022QC30).
文摘Proton-conducting materials have attracted considerable interest because of their extensive application in energy storage and conversion devices.Among them,metal-organic frameworks(MOFs)present tremendous development potential and possibilities for constructing novel advanced proton conductors due to their special advantages in crystallinity,designability,and porosity.In particular,several special design strategies for the structure of MOFs have opened new doors for the advancement of MOF proton conductors,such as charged network construction,ligand functionalization,metal-center manipulation,defective engineering,vip molecule incorporation,and pore-space manipulation.With the implementation of these strategies,proton-conducting MOFs have developed significantly and profoundly within the last decade.Therefore,in this review,we critically discuss and analyze the fundamental principles,design strategies,and implementation methods targeted at improving the proton conductivity of MOFs through representative examples.Besides,the structural features,the proton conduction mechanism and the behavior of MOFs are discussed thoroughly and meticulously.Future endeavors are also proposed to address the challenges of proton-conducting MOFs in practical research.We sincerely expect that this review will bring guidance and inspiration for the design of proton-conducting MOFs and further motivate the research enthusiasm for novel proton-conducting materials.
文摘This article aims to deepen the understanding of the role of Helicobacter pylori(H.pylori)infection in the development of cholelithiasis,initiated by the article by Yao et al,who investigated the potential link between H.pylori infection and the development of cholelithiasis through a multicenter retrospective study on an Asian population of over 70000 participants.They also performed a compre-hensive analysis of previously published studies on H.pylori and cholelithiasis,finding a positive association therein[odds ratio(OR)=1.103,P=0.049].Patients positive for H.pylori also had lower levels of total and direct bilirubin,but higher levels of total cholesterol and low-density lipoprotein cholesterol compared to uninfected patients(P<0.05).Cohort studies have confirmed that H.pylori is a risk factor for cholelithiasis(P<0.0001),and aggregate analyses of case-control and cross-sectional studies have shown a positive association between H.pylori and cholelithiasis in Asia(OR=1.599,P=0.034),but not in Europe(OR=1.277,P=0.246).Moreover,H.pylori appears to be related to a higher ratio of choledocho-lithiasis/cholecystolithiasis(OR=3.321,P=0.033).The authors conclude that H.pylori infection is positively correlated with cholelithiasis,particularly with the choledocholithiasis phenotype,especially in Asia,and it is potentially related to bilirubin and cholesterol metabolism.
基金National Natural Science Foundation of China,Grant/Award Numbers:52173091,62101391。
文摘Developing low-cost and high-performance nanofiber-based polyelectrolyte membranes for fuel cell applications is a promising solution to energy depletion.Due to the high specific surface area and one-dimensional longrange continuous structure of the nanofiber,ion-charged groups can be induced to form long-range continuous ion transfer channels in the nanofiber composite membrane,significantly increasing the ion conductivity of the membrane.This review stands apart from previous endeavors by offering a comprehensive overview of the strategies employed over the past decade in utilizing both electrospun and natural nanofibers as key components of proton exchange membranes and anion exchange membranes for fuel cells.Electrospun nanofibers are categorized based on their material properties into two primary groups:(1)ionomer nanofibers,inherently endowed with the ability to conduct H+(such as perfluorosulfonic acid or sulfonated poly(ether ether ketone))or OH-(e.g.,FAA-3),and(2)nonionic polymer nanofibers,comprising inert polymers like polyvinylidene difluoride,polytetrafluoroethylene,and polyacrylonitrile.Notably,the latter often necessitates surface modifications to impart ion transport channels,given their inherent proton inertness.Furthermore,this review delves into the recent progress made with three natural nanofibers derived from biodegradable cellulose—cellulose nanocrystals,cellulose nanofibers,and bacterial nanofibers—as crucial elements in polyelectrolyte membranes.The effect of the physical structure of such nanofibers on polyelectrolyte membrane properties is also briefly discussed.Lastly,the review emphasizes the challenges and outlines potential solutions for future research in the field of nanofiber-based polyelectrolyte membranes,aiming to propel the development of high-performance polymer electrolyte fuel cells.
基金National Key R&D Program of China,Grant/Award Number:2021YFA1500900Basic and Applied Basic Research Foundation of Guangdong Province-Regional Joint Fund Project,Grant/Award Number:2021B1515120024+9 种基金Science Funds of the Education Office of Jiangxi Province,Grant/Award Number:GJJ2201324Science Funds of Jiangxi Province,Grant/Award Numbers:20242BAB25168,20224BAB213018Doctoral Research Start-up Funds of JXSTNU,Grant/Award Number:2022BSQD05China Postdoctoral Science Foundation,Grant/Award Number:2023M741121National Natural Science Foundation of China,Grant/Award Number:22172047Provincial Natural Science Foundation of Hunan,Grant/Award Number:2021JJ30089Shenzhen Science and Technology Program,Grant/Award Number:JCYJ20210324122209025Changsha Municipal Natural Science Foundation,Grant/Award Number:kq2107008Hunan Province of Huxiang Talent project,Grant/Award Number:2023rc3118Natural Science Foundation of Hunan Province,Grant/Award Number:2022JJ10006.
文摘Hydrogen energy from electrocatalysis driven by sustainable energy has emerged as a solution against the background of carbon neutrality.Proton exchange membrane(PEM)-based electrocatalytic systems represent a promising technology for hydrogen production,which is equipped to combine efficiently with intermittent electricity from renewable energy sources.In this review,PEM-based electrocatalytic systems for H2 production are summarized systematically from low to high operating temperature systems.When the operating temperature is below 130℃,the representative device is a PEM water electrolyzer;its core components and respective functions,research status,and design strategies of key materials especially in electrocatalysts are presented and discussed.However,strong acidity,highly oxidative operating conditions,and the sluggish kinetics of the anode reaction of PEM water electrolyzers have limited their further development and shifted our attention to higher operating temperature PEM systems.Increasing the temperature of PEM-based electrocatalytic systems can cause an increase in current density,accelerate reaction kinetics and gas transport and reduce the ohmic value,activation losses,ΔGH*,and power consumption.Moreover,further increasing the operating temperature(120-300℃)of PEM-based devices endows various hydrogen carriers(e.g.,methanol,ethanol,and ammonia)with electrolysis,offering a new opportunity to produce hydrogen using PEM-based electrocatalytic systems.Finally,several future directions and prospects for developing PEM-based electrocatalytic systems for H_(2) production are proposed through devoting more efforts to the key components of devices and reduction of costs.
基金National Natural Science Foundation of China(No.52476192,No.52106237)Natural Science Foundation of Heilongjiang Province(No.YQ2022E027)。
文摘The transition of hydrogen sourcing from carbon-intensive to water-based methodologies is underway,with renewable energy-powered proton exchange membrane water electrolysis(PEMWE)emerging as the preeminent pathway for hydrogen production.Despite remarkable advancements in this field,confronting the sluggish electrochemical kinetics and inherent high-energy consumption arising from deteriorated mass transport within PEMWE systems remains a formidable obstacle.This impediment stems primarily from the hindered protons mass transfer and the untimely hydrogen bubbles detachment.To address these challenges,we harness the inherent variability of electrical energy and introduce an innovative pulsed dynamic water electrolysis system.Compared to constant voltage electrolysis(hydrogen production rate:51.6 m L h^(-1),energy consumption:5.37 kWh Nm-^(3)H_(2)),this strategy(hydrogen production rate:66 m L h^(-1),energy consumption:3.83 kWh Nm-^(3)H_(2))increases the hydrogen production rate by approximately 27%and reduces the energy consumption by about 28%.Furthermore,we demonstrate the practicality of this system by integrating it with an off-grid photovoltaic(PV)system designed for outdoor operation,successfully driving a hydrogen production current of up to 500 mA under an average voltage of approximately 2 V.The combined results of in-situ characterization and finite element analysis reveal the performance enhancement mechanism:pulsed dynamic electrolysis(PDE)dramatically accelerates the enrichment of protons at the electrode/solution interface and facilitates the release of bubbles on the electrode surface.As such,PDE-enhanced PEMWE represents a synergistic advancement,concurrently enhancing both the hydrogen generation reaction and associated transport processes.This promising technology not only redefines the landscape of electrolysis-based hydrogen production but also holds immense potential for broadening its application across a diverse spectrum of electrocatalytic endeavors.
基金funding from the European Union’s Horizon 2020 research and innovation program through the European IMPULSE project under Grant Agreement No.871161from LASERLAB-EUROPE V under Grant Agreement No.871124+6 种基金from the Grant Agency of the Czech Republic(Grant No.GM23-05027M)Grant No.PDC2021120933-I00 funded by MCIN/AEI/10.13039/501100011033by the European Union Next Generation EU/PRTRsupported by funding from the Ministerio de Ciencia,Innovación y Universidades in Spain through ICTS Equipment Grant No.EQC2018-005230-Pfrom Grant No.PID2021-125389O A-I00 funded by MCIN/AEI/10.13039/501100011033/FEDER,UEby“ERDF A Way of Making Europe”by the European Unionfrom grants of the Junta de Castilla y León with Grant Nos.CLP263P20 and CLP087U16。
文摘This work demonstrates experimentally the close relation between return currents from relativistic laser-driven target polarization and the quality of the relativistic laser–plasma interaction for laser-driven secondary sources,taking as an example ion acceleration by target normal sheath acceleration.The Pearson linear correlation of maximum return current amplitude and proton spectrum cutoff energy is found to be in the range from~0.70 to 0.94.kA-scale return currents rise in all interaction schemes where targets of any kind are charged by escaping laser-accelerated relativistic electrons.Their precise measurement is demonstrated using an inductive scheme that allows operation at high repetition rates.Thus,return currents can be used as a metrological online tool for the optimization of many laser-driven secondary sources and for diagnosing their stability.In particular,in two parametric studies of laser-driven ion acceleration,we carry out a noninvasive online measurement of return currents in a tape target system irradiated by the 1 PW VEGA-3 laser at Centro de Láseres Pulsados:first the size of the irradiated area is varied at best compression of the laser pulse;second,the pulse duration is varied by means of induced group delay dispersion at best focus.This work paves the way to the development of feedback systems that operate at the high repetition rates of PW-class lasers.
文摘To develop proton-conducting materials with high hydrothermal and acid-base stability and to elucidate the proton-transport mechanism through visualized structural analysis,two new lanthanum phosphite-oxalates with 3D frameworks,designated as[La(HPO_(3))(C_(2)O_(4))0.5(H_(2)O)_(2)](La‑1)and(C_(6)H_(16)N_(2))(H_(3)O)[La_(2)(H_(2)PO_(3))_(3)(C_(2)O_(4))_(3)(H_(2)O)](La‑2)(C_(6)H_(14)N_(2)=cis-2,6-dimethylpiperazine),were prepared by hydrothermal and solvothermal conduction,respectively.La‑1 was constructed with lanthanum phosphite 2D layers and C_(2)O_(4)^(2-)groups,whereas La‑2 was constructed with lanthanum oxalate 2D layers and H_(2)PO^(3-)groups.Alternating current(AC)impedance spectra indicate that the pro-ton conductivities of both compounds could reach 10^(-4)S·cm^(-1)and remain highly durable at 75℃and 98%of rela-tive humidity(RH).Due to the abundance of H-bonds in La‑2,theσof La‑2 was higher than that of La‑1.La‑1 exhibited excellent water and pH stability.CCDC:2439965,La‑1;443776,La‑2.
