水作为一种储量巨大且可循环利用的资源,可以被电解槽电化学分解为清洁的氢能和化学品氧气,从而实现环境友好的能源循环.与碱性电解槽相比,质子交换膜(PEM)电解槽具有明显优势,例如更高的电流密度、更高的电压效率、更低的欧姆损耗和更...水作为一种储量巨大且可循环利用的资源,可以被电解槽电化学分解为清洁的氢能和化学品氧气,从而实现环境友好的能源循环.与碱性电解槽相比,质子交换膜(PEM)电解槽具有明显优势,例如更高的电流密度、更高的电压效率、更低的欧姆损耗和更少的不利反应,使其成为生产氢能和氧气的最有希望的装置.作为电化学水分解的半反应之一,氧析出反应(OER)过程是一个四电子和四质子耦合的多步电化学反应,与双电子转移的氢析出发应(HER)相比,需要更高的能量来补偿缓慢的动力学过程.PEM电解槽中高的阳极电势和苛刻的腐蚀环境为阳极电催化剂设定了更高的选择标准,同时由于缺乏高活性和高稳定性的阳极电催化剂,限制了PEM电解槽的广泛应用.在这种条件下,适用的阳极电催化剂主要局限于钌(Ru)和铱(Ir)及其衍生物,因为其固有的电子结构使之具有较高的催化活性.然而,由于Ir的低地球丰度和高成本,人们更希望开发RuO2基电催化剂.遗憾的是,商业RuO2电催化剂在酸性介质中的OER过电位仍然过高,稳定性也比在碱性介质中低得多,无法满足实际应用的要求.此外,从实用角度出发,研究者始终希望提高贵金属Ru基电催化剂的本征活性以减少实际应用所需的催化剂量.因此,迫切需要改性RuO2基电催化剂以提升其在酸性介质中的析氧反应催化活性.迄今,研究已经证实活性中间体*OOH的形成是酸性介质中OER的速率决定步骤(RDS),但是RuO2基催化剂中Ru^4+活性位点对活性中间体*OOH的吸附过强,导致商用RuO2具有约300 mV的过电势(10 mA cm^-2).为了减弱*OOH在Ru^4+活性位点上的吸附能并降低RDS能垒,研究人员做了大量的试验来调节Ru^4+活性位点的电子结构,包括杂原子掺杂和制备Ru基固溶体.应变效应也是调整合金催化剂电子结构的有效策略.在RuO2中利用应变来调节Ru^4+活性位点的电子结构进而增强其在酸性介质中的OER催化活性是一种简便的手段,但是形成稳定的应变而不引入任何杂原子仍然是一个巨大的挑战.本文首次在不掺杂任何杂原子的情况下,采用一步激光辐照法合成了高效的Ru@RuO2-L电催化剂,利用Ru@RuO2核壳纳米颗粒RuO2壳层的拉伸应变,有效调节了Ru^4+的电荷密度,其本征活性显著增强,酸性水氧化的过电位大大降低,远远低于商用RuO2催化剂.X射线精细吸收结构(XAFS)显示Ru-O键中存在6%的拉伸应变,X射线光电子能谱(XPS)和电子能量损失谱(EELS)表明Ru^4+的价态明显增加.Ru@RuO2-L催化剂在酸性电解液中表现出191 mV的极低过电位(10 mA cm^-2),这是迄今为止报道的不借助杂原子修饰的高效Ru基电催化剂的最低值,其面积比活性和质量比活性分别比商用RuO2催化剂高4倍和18倍.当使用Ru@RuO2-L作为阳极催化剂在酸性电解液中进行整体水分解时,双电极系统只需要1.45 V的极低的外加电压使系统达到10 mA cm^-2电流密度.酸性析氧活性的大幅度提高归因于由拉伸应变引起的Ru^4+电荷密度的降低,从而削弱了*OOH在Ru^X+(4<X<5)活性位点上的吸附能.展开更多
The Data Platform of Resource and Environment—whose data mainly come from field observation stations,spatial observations,and internet service institutions—is the base of data analysis and model simulation in geosci...The Data Platform of Resource and Environment—whose data mainly come from field observation stations,spatial observations,and internet service institutions—is the base of data analysis and model simulation in geoscience research in China.Among this integrated data platform,the tasks of the data platform of field observation stations are principally data collection,management,assimilation,and share service.Taking into consideration the distributing characteristics of the data sources and the service objects,the authors formulated the framework of the field observation stations' data platform based on the grid technology and designed its operating processes.The authors have further defined and analyzed the key functions and implementing techniques for each module.In a Linux operating system,validation tests for the data platform's function on data replication,data synchronization,and unified data service have been conducted under an environment that of the simulating field stations.展开更多
Creating lattice defects and alloying to produce strain effect in Pt-based bimetallic alloys are both effective methods to optimize the crystal and electronic structure and improve the electrocatalytic performance.Unf...Creating lattice defects and alloying to produce strain effect in Pt-based bimetallic alloys are both effective methods to optimize the crystal and electronic structure and improve the electrocatalytic performance.Unfortunately,the principles that govern the alkaline hydrogen evolution reaction(HER)performance remain unclear,which is detrimental to the rational design of efficient Pt-based electrocatalysts.Herein,PtNi alloys with different Pt/Ni ratios and edge dislocations were synthesized,and the effects of Pt/Ni composition and edge dislocations on the alkaline HER electrocatalytic activity of PtNi alloys were systematically studied.Combined experimental and theoretical investigations reveal that tuning Pt/Ni ratio results in only 1.1 times enhancements in Pt mass activity,whereas edge dislocations-induced extra tensile strain on Ni site and compressive strain on Pt site further boost the alkaline HER intrinsic activity at all Pt/Ni ratios.Impressively,the introduction of edge dislocations in PtNi alloys could break the limit of alloying in boosting Pt mass activity and result in up to 13.7-fold enhancement,in the case that Pt and Ni contents are nearly identical and thus edge dislocation density reaches the maximum.Fundamental mechanism studies demonstrate that the edge dislocation strategy could make a breakthrough in facilitating water dissociation kinetics of PtNi alloys.展开更多
There are many complex eye diseases which are the leading causes of blindness,however,the pathogenesis of the complex eye diseases is not fully understood,especially the underlying molecular mechanisms of N6-methylade...There are many complex eye diseases which are the leading causes of blindness,however,the pathogenesis of the complex eye diseases is not fully understood,especially the underlying molecular mechanisms of N6-methyladenosine(m6A)RNA methylation in the eye diseases have not been extensive clarified.Our review summarizes the latest advances in the studies of m6A modification in the pathogenesis of the complex eye diseases,including cornea disease,cataract,diabetic retinopathy,age-related macular degeneration,proliferative vitreoretinopathy,Graves’disease,uveal melanoma,retinoblastoma,and traumatic optic neuropathy.We further discuss the possibility of developing m6A modification signatures as biomarkers for the diagnosis of the eye diseases,as well as potential therapeutic approaches.展开更多
Developing highly efficient non-R catalysts for fuel cells and metal-air batteries is highly desirable but still challenging due to the sluggish oxygen reduction reaction(ORR).Herein,a facile and efficient strategy is...Developing highly efficient non-R catalysts for fuel cells and metal-air batteries is highly desirable but still challenging due to the sluggish oxygen reduction reaction(ORR).Herein,a facile and efficient strategy is demonstrated to prepare N-doped carbon encapsulated ordered Pd-Fe intermetallic(O-Pd-Fe@NC/C)nanoparticles via a one-step thermal annealing method.The obtained O-Pd-Fe@NC/C nanoparticles show enhanced ORR activity,durability and anti-poisoning capacity in both acid and alkaline medium.When O-Pd-Fe@NC/C serving as cathode catalyst for Zn-air battery,it exhibits higher voltage platform and superior cycling performance with respect to the Zn-air battery based on the mixture of Pt/C and Ir/C catalysts.The enhanced electrocatalytic performance can be ascribed to the formation of face-centered tetragonal(fct)Pd-Fe nanoparticles,the protective action of the N-doped carbon layer and the interface confinement effect between them.The in situ formed N-doped carbon shell not only restrains the Pd-Fe ordered intermetallics from aggregating effectively during the thermal annealing process,but also provides a strong anchoring effect to avoid the detachment of Pd-Fe nanoparticles from the carbon support during the potential cycling.This facile carbon encapsulation strategy may also be extended to the preparation of a wide variety of N-doped carbon encapsulated intermetallic compounds for fuel cell application.展开更多
文摘水作为一种储量巨大且可循环利用的资源,可以被电解槽电化学分解为清洁的氢能和化学品氧气,从而实现环境友好的能源循环.与碱性电解槽相比,质子交换膜(PEM)电解槽具有明显优势,例如更高的电流密度、更高的电压效率、更低的欧姆损耗和更少的不利反应,使其成为生产氢能和氧气的最有希望的装置.作为电化学水分解的半反应之一,氧析出反应(OER)过程是一个四电子和四质子耦合的多步电化学反应,与双电子转移的氢析出发应(HER)相比,需要更高的能量来补偿缓慢的动力学过程.PEM电解槽中高的阳极电势和苛刻的腐蚀环境为阳极电催化剂设定了更高的选择标准,同时由于缺乏高活性和高稳定性的阳极电催化剂,限制了PEM电解槽的广泛应用.在这种条件下,适用的阳极电催化剂主要局限于钌(Ru)和铱(Ir)及其衍生物,因为其固有的电子结构使之具有较高的催化活性.然而,由于Ir的低地球丰度和高成本,人们更希望开发RuO2基电催化剂.遗憾的是,商业RuO2电催化剂在酸性介质中的OER过电位仍然过高,稳定性也比在碱性介质中低得多,无法满足实际应用的要求.此外,从实用角度出发,研究者始终希望提高贵金属Ru基电催化剂的本征活性以减少实际应用所需的催化剂量.因此,迫切需要改性RuO2基电催化剂以提升其在酸性介质中的析氧反应催化活性.迄今,研究已经证实活性中间体*OOH的形成是酸性介质中OER的速率决定步骤(RDS),但是RuO2基催化剂中Ru^4+活性位点对活性中间体*OOH的吸附过强,导致商用RuO2具有约300 mV的过电势(10 mA cm^-2).为了减弱*OOH在Ru^4+活性位点上的吸附能并降低RDS能垒,研究人员做了大量的试验来调节Ru^4+活性位点的电子结构,包括杂原子掺杂和制备Ru基固溶体.应变效应也是调整合金催化剂电子结构的有效策略.在RuO2中利用应变来调节Ru^4+活性位点的电子结构进而增强其在酸性介质中的OER催化活性是一种简便的手段,但是形成稳定的应变而不引入任何杂原子仍然是一个巨大的挑战.本文首次在不掺杂任何杂原子的情况下,采用一步激光辐照法合成了高效的Ru@RuO2-L电催化剂,利用Ru@RuO2核壳纳米颗粒RuO2壳层的拉伸应变,有效调节了Ru^4+的电荷密度,其本征活性显著增强,酸性水氧化的过电位大大降低,远远低于商用RuO2催化剂.X射线精细吸收结构(XAFS)显示Ru-O键中存在6%的拉伸应变,X射线光电子能谱(XPS)和电子能量损失谱(EELS)表明Ru^4+的价态明显增加.Ru@RuO2-L催化剂在酸性电解液中表现出191 mV的极低过电位(10 mA cm^-2),这是迄今为止报道的不借助杂原子修饰的高效Ru基电催化剂的最低值,其面积比活性和质量比活性分别比商用RuO2催化剂高4倍和18倍.当使用Ru@RuO2-L作为阳极催化剂在酸性电解液中进行整体水分解时,双电极系统只需要1.45 V的极低的外加电压使系统达到10 mA cm^-2电流密度.酸性析氧活性的大幅度提高归因于由拉伸应变引起的Ru^4+电荷密度的降低,从而削弱了*OOH在Ru^X+(4<X<5)活性位点上的吸附能.
基金supported by the Incubation Foundation for Special Disciplines of National Science Foundation of China (NSFC) (grant number: J0630966)Chinese Research Network on Special Environment and Disaster (CRENSED) of Ministry of Science and Technology of the People’s Republic of China (grant number:1Z2005DKA10600)the Knowledge Innovation Important Program of Chinese Academy of Sciences (Grant Number:NF105-SDB-1-21)
文摘The Data Platform of Resource and Environment—whose data mainly come from field observation stations,spatial observations,and internet service institutions—is the base of data analysis and model simulation in geoscience research in China.Among this integrated data platform,the tasks of the data platform of field observation stations are principally data collection,management,assimilation,and share service.Taking into consideration the distributing characteristics of the data sources and the service objects,the authors formulated the framework of the field observation stations' data platform based on the grid technology and designed its operating processes.The authors have further defined and analyzed the key functions and implementing techniques for each module.In a Linux operating system,validation tests for the data platform's function on data replication,data synchronization,and unified data service have been conducted under an environment that of the simulating field stations.
基金the National Natural Science Foundation of China(No.51822106).
文摘Creating lattice defects and alloying to produce strain effect in Pt-based bimetallic alloys are both effective methods to optimize the crystal and electronic structure and improve the electrocatalytic performance.Unfortunately,the principles that govern the alkaline hydrogen evolution reaction(HER)performance remain unclear,which is detrimental to the rational design of efficient Pt-based electrocatalysts.Herein,PtNi alloys with different Pt/Ni ratios and edge dislocations were synthesized,and the effects of Pt/Ni composition and edge dislocations on the alkaline HER electrocatalytic activity of PtNi alloys were systematically studied.Combined experimental and theoretical investigations reveal that tuning Pt/Ni ratio results in only 1.1 times enhancements in Pt mass activity,whereas edge dislocations-induced extra tensile strain on Ni site and compressive strain on Pt site further boost the alkaline HER intrinsic activity at all Pt/Ni ratios.Impressively,the introduction of edge dislocations in PtNi alloys could break the limit of alloying in boosting Pt mass activity and result in up to 13.7-fold enhancement,in the case that Pt and Ni contents are nearly identical and thus edge dislocation density reaches the maximum.Fundamental mechanism studies demonstrate that the edge dislocation strategy could make a breakthrough in facilitating water dissociation kinetics of PtNi alloys.
基金supported by the National Natural Science Foundation of China(No.81873681,2018,81770952,2017)the Basic Research Project of Henan Eye Hospital,China(No.20JCQN005,2020).
文摘There are many complex eye diseases which are the leading causes of blindness,however,the pathogenesis of the complex eye diseases is not fully understood,especially the underlying molecular mechanisms of N6-methyladenosine(m6A)RNA methylation in the eye diseases have not been extensive clarified.Our review summarizes the latest advances in the studies of m6A modification in the pathogenesis of the complex eye diseases,including cornea disease,cataract,diabetic retinopathy,age-related macular degeneration,proliferative vitreoretinopathy,Graves’disease,uveal melanoma,retinoblastoma,and traumatic optic neuropathy.We further discuss the possibility of developing m6A modification signatures as biomarkers for the diagnosis of the eye diseases,as well as potential therapeutic approaches.
基金This work was supported by the N ational Natural Science Foundation of C hina(No.91963109)the Fundamental Research Funds for the C entral Universities(No.2172019kfyRCPY100).The authors thank the Analytical and Testing Center of HUST for allowing the use of its help and facilities for XRD and XPSThis research used resources of the UCIM RI facilities and the Center for Functional Nanomaterials,which is a U.S.DOE Office of Science Facility,at Brookhaven National Laboratory under Contract No.DE-SC0012704.
文摘Developing highly efficient non-R catalysts for fuel cells and metal-air batteries is highly desirable but still challenging due to the sluggish oxygen reduction reaction(ORR).Herein,a facile and efficient strategy is demonstrated to prepare N-doped carbon encapsulated ordered Pd-Fe intermetallic(O-Pd-Fe@NC/C)nanoparticles via a one-step thermal annealing method.The obtained O-Pd-Fe@NC/C nanoparticles show enhanced ORR activity,durability and anti-poisoning capacity in both acid and alkaline medium.When O-Pd-Fe@NC/C serving as cathode catalyst for Zn-air battery,it exhibits higher voltage platform and superior cycling performance with respect to the Zn-air battery based on the mixture of Pt/C and Ir/C catalysts.The enhanced electrocatalytic performance can be ascribed to the formation of face-centered tetragonal(fct)Pd-Fe nanoparticles,the protective action of the N-doped carbon layer and the interface confinement effect between them.The in situ formed N-doped carbon shell not only restrains the Pd-Fe ordered intermetallics from aggregating effectively during the thermal annealing process,but also provides a strong anchoring effect to avoid the detachment of Pd-Fe nanoparticles from the carbon support during the potential cycling.This facile carbon encapsulation strategy may also be extended to the preparation of a wide variety of N-doped carbon encapsulated intermetallic compounds for fuel cell application.
