With the first rays of dawn peeking through the rainforest at Shiti Village,Dehong Dai and Jingpo Autonomous Prefecture,Yunnan Province,Xu Xiaolong,a bird-watching guide from the Jingpo ethnic group,led a German bird-...With the first rays of dawn peeking through the rainforest at Shiti Village,Dehong Dai and Jingpo Autonomous Prefecture,Yunnan Province,Xu Xiaolong,a bird-watching guide from the Jingpo ethnic group,led a German bird-watching group into the jungle.His great-grandfather made a living by hunting“weird-looking birds”in the mountains.Today,the birds(Great Hornbill)are attracting tourist dollars from other parts of the world without dodging bullets.In Shiti Village,bird-watchers can enjoy the chirping of Great Hornbills and feel the rumbling in the air as the birds fly past.The village on the Chinese border with Myanmar was formerly poverty-stricken,with an average annual income of barely 2,000 yuan(US$305)per household 10 years ago.Today,the average annual income has grown to 150,000 yuan(US$23,075).It is a shining example of the successful practice of the notion that“lucid waters and lush mountains are invaluable assets.”展开更多
The development of cost-effective catalysts for hydrogen evolution reaction(HER)and hydrogen oxidation reaction(HOR)is the key to realizing alkaline fuel cells and water electrolytic cells applications.Early reports h...The development of cost-effective catalysts for hydrogen evolution reaction(HER)and hydrogen oxidation reaction(HOR)is the key to realizing alkaline fuel cells and water electrolytic cells applications.Early reports have shown that surface modification of Pt-based catalysts with highly oxygenophilic metals can significantly enhance their HOR/HER activity.Here,we successfully synthesized uniform trimetallic PdPtNi hollow nanocages(PdPtNi HNCs)with excellent HER and HOR activity under alkaline media via hydrothermal deposition of oxygenophilic Ni on PdPt HNCs.Moreover,the PdPtNi HNCs exhibit superior HER/HOR durability and excellent CO-tolerance in HOR,compared with commercial Pt/C catalyst.The theoretical calculations confirm that the introduced Ni enriched the electronic and balanced the interactions of the adsorbed intermediates(OHad and Had)on the catalyst’s surface,thus promoting the HER and HOR activity.This work provides a promising approach for designing and synthesizing bifunctional and highly efficient catalysts.展开更多
运用HoR(House of Reliability)思想,将故障树分析(FTA)、失效模式影响及危害性分析(FMECA)整合于质量功能配置(QFD)中,建立可靠性配置流程:对系统可靠性指标进行分配,解决了传统方法过度依赖于主观打分的问题;在此基础上,建立以顾客可...运用HoR(House of Reliability)思想,将故障树分析(FTA)、失效模式影响及危害性分析(FMECA)整合于质量功能配置(QFD)中,建立可靠性配置流程:对系统可靠性指标进行分配,解决了传统方法过度依赖于主观打分的问题;在此基础上,建立以顾客可靠性满意度最大和配置成本最低为目标的模型,将可靠性指标配置到具体的工程技术特征上。并以数控车床电主轴为例,对模型的有效性进行了验证。展开更多
OBJECTIVE:To evaluate the effects of electric acupoint stimulation on gastrointestinal hormones and motility among geriatric postoperative patients with gastrointestinal tumors,and to explore an efficient and noninvas...OBJECTIVE:To evaluate the effects of electric acupoint stimulation on gastrointestinal hormones and motility among geriatric postoperative patients with gastrointestinal tumors,and to explore an efficient and noninvasive method for postoperative recovery of bowel functions.METHODS:Forty patients were randomly and evenly assigned into a regular nursing care group(RNC) and an acupoint electric stimulation group(AES).Patients in the RNC group received regular nursing care and patients in the AES group received regular nursing care plus electric stimulation of acupoints.The serum levels of gastrin(GAS),motilin(MOT),and cholecystokinin(CCK),and an electrogastrogram(EGG) of all the patients were evaluated on the first,third,and fifth day after surgery.The time to first flatus after surgery and the number of patients with side effects such as abdominal pain,abdominal distention,and diarrhea were recorded.RESULTS:There were significant differences between the two groups in GAS,MOT,EGG,time to first flatus,abdominal pain,abdominal distention,and diarrhea(P < 0.05).CONCLUSION:Electric stimulation on acupoints could increase levels of GAS and MOT,promote the recovery of gastrointestinal functions,and decrease complications among postoperative senile patients with gastrointestinal tumors.展开更多
Exploring platinum-group-metal(PGM)free electrocatalysts for hydrogen oxidation reaction(HOR)in alkaline media is essential to the progress of anion exchange membrane fuel cells(AEMFCs).In this work,a Ni/MoO_(2) heter...Exploring platinum-group-metal(PGM)free electrocatalysts for hydrogen oxidation reaction(HOR)in alkaline media is essential to the progress of anion exchange membrane fuel cells(AEMFCs).In this work,a Ni/MoO_(2) heterostructure catalyst with comparable HOR activity in alkaline electrolyte with PGM catalyst was prepared by a simple hydrothermal-reduction method.Remarkably,the Ni/MoO_(2) presents a mass kinetic current density of 38.5 mA mgNi^(-1) at the overpotential of 50 mV,which is higher than that of the best PGM free HOR catalyst reported by far.Moreover,the HOR performance of Ni/MoO_(2) under 100 ppm CO shows negligible fading,together with the superior durability,render it significant potential for application in AEMFCs.A particular mechanistic study indicates that the excellent HOR performance is ascribed to the accelerated Volmer step by the incorporation of MoO_(2).The function of MoO_(2) was further confirmed by CO striping experiment on Pt/C-MoO_(2) that MoO_(2) can facilitated OH adsorption thus accelerate the HOR process.On account of the high performance and low cost,the Ni/MoO_(2) electrocatalyst encourages the establishment of high performance PGM free catalyst and shows significant potential for application in AEMFCs.展开更多
Journal of Materials Sciences & Technology is a monthly journal for the rapid dissemination of new, important results in material and related fields. Submission Electronic files of MS Word and PDF are acceptable. ...Journal of Materials Sciences & Technology is a monthly journal for the rapid dissemination of new, important results in material and related fields. Submission Electronic files of MS Word and PDF are acceptable. Please visit http://www.jmst.org and submit online. Submission of a manuscript must be the original work of the author(s) and has not been published elsewhere or under consideration for another publication, or a substantially similar form in any language.展开更多
Enabling the conversion of chemical energy of fuels directly into electricity without combustion,fuel cells are arousing great interest in both academia and industry.A typical case is the proton exchange membrane fuel...Enabling the conversion of chemical energy of fuels directly into electricity without combustion,fuel cells are arousing great interest in both academia and industry.A typical case is the proton exchange membrane fuel cell(PEMFC),already commercialized by automobile giants.For mass popularization,however,three major criteria must be balanced:performance,durability and cost.The electrocatalysts used in both the anode and cathode are the kernel of PEMFCs,being essential for efficient operation.First in the firing‐line is the oxygen reduction reaction(ORR)at the cathode,which is normally very sluggish:over six orders of magnitude slower than the anode hydrogen oxidation reaction(HOR)[1].Thus,considerable efforts have been made to improve the cathode ORR.Identifying the main active sites is key to the design of optimum materials for enhanced ORR.Considering the complex balance of preparation,performance and cost,the active sites of metal‐nitrogen‐carbon(M‐N‐C)catalysts are particularly promising.Coupled with the single metal atom(SMA)catalysts[2–5],two excellent M‐N‐C catalysts were recently reported[6,7].New insights were thereby gained into the delicate architecture of carbon‐based SMA catalysts for ORR.展开更多
39 mol% SiC of ceramic pellets ZrB<sub>2</sub>-αSiC and TiB<sub>2</sub>-αSiC were synthesized by the reactive hot pressure RHP process at 1850°C under 40 Mpa in vacuum. The XR diffrac...39 mol% SiC of ceramic pellets ZrB<sub>2</sub>-αSiC and TiB<sub>2</sub>-αSiC were synthesized by the reactive hot pressure RHP process at 1850°C under 40 Mpa in vacuum. The XR diffraction displays the absence of other reagents apart from ZrB<sub>2</sub>, SiC and TiB<sub>2</sub> confirming the purity of the pellets. The cathodic exploitation of both of them through electrochemical study shows that TiB<sub>2</sub>-αSiC is the most active for Hydrogen Evolution Reaction (HER) and Hydrogen Oxidation Reaction (HOR) in 0.5 M of H<sub>2</sub>SO<sub>4</sub> solution at room temperature. Moreover, the kinetic exploitation shows that for both pellets the system is controlled by mass transport when they are used as HER. However, in the case of HOR, the system is controlled by the electron transfer.展开更多
Ruthenium(Ru)is a promising electrocatalyst for hydrogen oxidation reaction(HOR)due to the similar metal hydrogen bond energy to Pt.However,Ru is easily deactivated or dissolved under an oxidation potential,which make...Ruthenium(Ru)is a promising electrocatalyst for hydrogen oxidation reaction(HOR)due to the similar metal hydrogen bond energy to Pt.However,Ru is easily deactivated or dissolved under an oxidation potential,which makes it unavailable in proton exchange membrane fuel cells.In this work,ultrastable Ru-based electrocatalysts for HOR in high-temperature polymer electrolyte membrane fuel cells(HTPEMFCs)were developed by Mo doping.Under the operation conditions of HT-PEMFCs,thermal reduction inhibited the production of amorphous Ru oxide(RuO_(2))in the Ru-based electrocatalysts during the HOR.Mo doping significantly improved the stability of the electrocatalyst by decreasing the reduction temperature of RuO_(2)and accelerating the HOR by reducing the adsorption of H*.RuMo/C exhibited excellent HOR activity at high temperatures due to thermal reduction inhibition of electrooxidation;the fabricated HT-PEMFCs exhibited long-term stability and a 1050 mW cm^(−2)peak power density,comparable to the commercial Pt catalyst.This work provides a novel strategy for designing electrocatalysts by combining material intrinsic properties and work conditions,which could promote the development of advanced electrocatalysts for HT-PEMFCs.展开更多
本文通过对众多最近才出版的非常重要的西藏医学文献的简要调查,探讨了西藏医学几个方面的问题。传统的西藏医学是本土的、印度的、汉地的和近东的有关身体和疾病、诊断学、治疗学理论的结合,但为什么印语的医学传统明显影响最大?萨霍...本文通过对众多最近才出版的非常重要的西藏医学文献的简要调查,探讨了西藏医学几个方面的问题。传统的西藏医学是本土的、印度的、汉地的和近东的有关身体和疾病、诊断学、治疗学理论的结合,但为什么印语的医学传统明显影响最大?萨霍尔之地,今天的孟加拉国,在它的构成中也发挥了作用,尽管作用小一些。本文作为明显是由一位萨霍尔国王所写的几个相对简要的医学教法的前言,同时也希冀能够为几位重要的西藏医生如宇妥·云丹衮布(12世纪早期)、拉杰·金巴·才旺(16世纪)和西藏医学章替派的一些成员提供更为充足的断代依据。最后,非常初步地、表面地调查了(一位)萨霍尔王直接或间接发挥作用的教法的论述,即《拳头十万》(Khu tshur’bum)和《十万拳头》(’Bum khu tshur),并厘定传记的细节,这些包括哈若恰(拉)杜,他的家族与异源教法文集有着密切的联系。展开更多
Single-atom catalysts(SACs),which contain a single metal atom supported on a well-confined substrate,are among the most promising heterogeneous catalysts owing to their unique advantages,such as high intrinsic activit...Single-atom catalysts(SACs),which contain a single metal atom supported on a well-confined substrate,are among the most promising heterogeneous catalysts owing to their unique advantages,such as high intrinsic activity and selectivity,tunable bonds and coordination,abundant metal-containing active sites,and atomic economy.Since metal-support interactions(MSIs)in SACs exert a substantial influence on the catalytic properties,gaining a profound understanding and recognition of catalytic reactions depends greatly on investigating MSIs both experimentally and computationally.Hence,the engineer-ing and modulation of MSIs are regarded as one of the most efficient methods to rationally design SACs with disruptively enhanced catalytic properties.In this review,we track the recent advances in SACs from an MSI perspective.We then discuss the existing MSIs in SACs and elucidate the significant role of strong MSIs in catalytic properties and mechanisms.The chal-lenges hindering the rational design of supported SACs with strong MSIs,which are currently still far from being completely understood and overcome,are described.In addition,the correlation between strong MSIs and electrocatalytic activities in SACs,including an outlook to increase our understanding of MSIs,is discussed.Finally,the present review provides some perspectives and an in-depth understanding of strong MSIs to advance high-performing SACs.展开更多
To achieve the goals of the peak carbon dioxide emissions and carbon neutral,the development and utilization of sustainable clean energy are extremely important.Hydrogen fuel cells are an important system for converti...To achieve the goals of the peak carbon dioxide emissions and carbon neutral,the development and utilization of sustainable clean energy are extremely important.Hydrogen fuel cells are an important system for converting hydrogen energy into electrical energy.However,the slow hydrogen oxidation reaction(HOR)kinetics under alkaline conditions has limited its development.Therefore,elucidating the catalytic mechanism of HOR in acidic and alkaline media is of great significance for the construction of highly active and stable catalysts.In terms of practicality,Pt is still the primary choice for commercialization of fuel cells.On the above basis,we first introduced the hydrogen binding energy theory and bifunctional theory used to describe the HOR activity,as well as the pH dependence.After that,the rational design strategies of Pt-based HOR catalysts were systematically classified and summarized from the perspective of activity descriptors.In addition,we further emphasized the importance of theoretical simulations and in situ characterization in revealing the HOR mechanism,which is crucial for the rational design of catalysts.Moreover,the practical application of Pt-based HOR catalysts in fuel cells was also presented.In closing,the current challenges and future development directions of HOR catalysts were discussed.This review will provide a deep understanding for exploring the mechanism of highly efficient HOR catalysts and the development of fuel cells.展开更多
In this paper the electrochemical properties of some platinum-based nanoalloys are reviewed.The revision is centered on electrocatalytic materials generated via the carbonyl chemical route(CCR).In considering the effe...In this paper the electrochemical properties of some platinum-based nanoalloys are reviewed.The revision is centered on electrocatalytic materials generated via the carbonyl chemical route(CCR).In considering the effects of segregation in these bimetals,the reaction of the hydrogen oxidation(HOR)and oxygen reduction(ORR)in the alkaline medium was investigated.The reaction kinetics of these electrochemical processes in the alkaline electrolyte is still a challenge.For the design of high-performance platinum-based electrocatalysts,it is of importance to know that the kinetics of HOR and ORR also depends on the Pt adsorbate.The electrochemical analysis,based on the study of Pt nanoalloyed surfaces with different Pt-adsorbate interactions,was taken into account.A clear trend in the HOR as well as the ORR activity,in the alkaline electrolyte,was established,revealing that the activity changes in the order PtSn/C<PtCr/C<Pt/C(JM)<PtCo/C<PtNi/C for the former,and for the latter Pt/C(Tek)<Pt/C(JM)<PtCr/C<PtNi/C.The decisive effect of the Pt-H_(ad)energy on the HOR kinetics on Pt surfaces apparently depends on the oxophilicity role of the metal to favor M-OH_(ad).The apparent electronic effect is not evident on these materials,except if a strong metal interaction is induced per se with either the carbon or oxide supports,e.g.,the Pt/SnO_(2)-C interface in acidic media.Favorable effects of Pt-H_(ad)energy on HOR kinetics were found with the oxophilicity of the sp^(2)domains of carbon that serve as anchoring or nucleation sites for platinum atoms.These results were compared with the literature data,and it turns out that this type of strong metal support interaction(SMSI)modification is favorably induced by UV–VIS irradiation and outperforms Pt-Mmaterials to some extent.Either for HOR or ORR,it is shown that non-noble metals not only act as a surrogate metal for Pt utilization by inducing a compressive stress effect between the Pt atoms in the outermost layer but also participate in the electrocatalytic reaction.This information is important to understand and develop structures with the Pt/C catalyst for the manufacture of electrode materials in the alkaline medium.展开更多
文摘With the first rays of dawn peeking through the rainforest at Shiti Village,Dehong Dai and Jingpo Autonomous Prefecture,Yunnan Province,Xu Xiaolong,a bird-watching guide from the Jingpo ethnic group,led a German bird-watching group into the jungle.His great-grandfather made a living by hunting“weird-looking birds”in the mountains.Today,the birds(Great Hornbill)are attracting tourist dollars from other parts of the world without dodging bullets.In Shiti Village,bird-watchers can enjoy the chirping of Great Hornbills and feel the rumbling in the air as the birds fly past.The village on the Chinese border with Myanmar was formerly poverty-stricken,with an average annual income of barely 2,000 yuan(US$305)per household 10 years ago.Today,the average annual income has grown to 150,000 yuan(US$23,075).It is a shining example of the successful practice of the notion that“lucid waters and lush mountains are invaluable assets.”
基金supported by the National Natural Science Foundation of China(Nos.52171145,52472302,22105146,52331009,and 52272088).
文摘The development of cost-effective catalysts for hydrogen evolution reaction(HER)and hydrogen oxidation reaction(HOR)is the key to realizing alkaline fuel cells and water electrolytic cells applications.Early reports have shown that surface modification of Pt-based catalysts with highly oxygenophilic metals can significantly enhance their HOR/HER activity.Here,we successfully synthesized uniform trimetallic PdPtNi hollow nanocages(PdPtNi HNCs)with excellent HER and HOR activity under alkaline media via hydrothermal deposition of oxygenophilic Ni on PdPt HNCs.Moreover,the PdPtNi HNCs exhibit superior HER/HOR durability and excellent CO-tolerance in HOR,compared with commercial Pt/C catalyst.The theoretical calculations confirm that the introduced Ni enriched the electronic and balanced the interactions of the adsorbed intermediates(OHad and Had)on the catalyst’s surface,thus promoting the HER and HOR activity.This work provides a promising approach for designing and synthesizing bifunctional and highly efficient catalysts.
文摘运用HoR(House of Reliability)思想,将故障树分析(FTA)、失效模式影响及危害性分析(FMECA)整合于质量功能配置(QFD)中,建立可靠性配置流程:对系统可靠性指标进行分配,解决了传统方法过度依赖于主观打分的问题;在此基础上,建立以顾客可靠性满意度最大和配置成本最低为目标的模型,将可靠性指标配置到具体的工程技术特征上。并以数控车床电主轴为例,对模型的有效性进行了验证。
基金Supported by the National Natural Science Foundation Project of China(Transcutaneous Electrical Acupoint Stimulation Prevents the Deep Vein Thrombosis:the Role of Endothelium Modulation,No.81202750)
文摘OBJECTIVE:To evaluate the effects of electric acupoint stimulation on gastrointestinal hormones and motility among geriatric postoperative patients with gastrointestinal tumors,and to explore an efficient and noninvasive method for postoperative recovery of bowel functions.METHODS:Forty patients were randomly and evenly assigned into a regular nursing care group(RNC) and an acupoint electric stimulation group(AES).Patients in the RNC group received regular nursing care and patients in the AES group received regular nursing care plus electric stimulation of acupoints.The serum levels of gastrin(GAS),motilin(MOT),and cholecystokinin(CCK),and an electrogastrogram(EGG) of all the patients were evaluated on the first,third,and fifth day after surgery.The time to first flatus after surgery and the number of patients with side effects such as abdominal pain,abdominal distention,and diarrhea were recorded.RESULTS:There were significant differences between the two groups in GAS,MOT,EGG,time to first flatus,abdominal pain,abdominal distention,and diarrhea(P < 0.05).CONCLUSION:Electric stimulation on acupoints could increase levels of GAS and MOT,promote the recovery of gastrointestinal functions,and decrease complications among postoperative senile patients with gastrointestinal tumors.
基金financially supported by the National Natural Science Foundation(91963109)the Fundamental Research Funds for the Central Universities(2172019kfy RCPY100)。
文摘Exploring platinum-group-metal(PGM)free electrocatalysts for hydrogen oxidation reaction(HOR)in alkaline media is essential to the progress of anion exchange membrane fuel cells(AEMFCs).In this work,a Ni/MoO_(2) heterostructure catalyst with comparable HOR activity in alkaline electrolyte with PGM catalyst was prepared by a simple hydrothermal-reduction method.Remarkably,the Ni/MoO_(2) presents a mass kinetic current density of 38.5 mA mgNi^(-1) at the overpotential of 50 mV,which is higher than that of the best PGM free HOR catalyst reported by far.Moreover,the HOR performance of Ni/MoO_(2) under 100 ppm CO shows negligible fading,together with the superior durability,render it significant potential for application in AEMFCs.A particular mechanistic study indicates that the excellent HOR performance is ascribed to the accelerated Volmer step by the incorporation of MoO_(2).The function of MoO_(2) was further confirmed by CO striping experiment on Pt/C-MoO_(2) that MoO_(2) can facilitated OH adsorption thus accelerate the HOR process.On account of the high performance and low cost,the Ni/MoO_(2) electrocatalyst encourages the establishment of high performance PGM free catalyst and shows significant potential for application in AEMFCs.
文摘Journal of Materials Sciences & Technology is a monthly journal for the rapid dissemination of new, important results in material and related fields. Submission Electronic files of MS Word and PDF are acceptable. Please visit http://www.jmst.org and submit online. Submission of a manuscript must be the original work of the author(s) and has not been published elsewhere or under consideration for another publication, or a substantially similar form in any language.
基金Support by the Jilin Province/Jilin University co-Construction Project-Funds for New Materials (SXGJSF2017-3, Branch-2/440050316A36)the National Key R&D Program of China (2016YFA0200400)+3 种基金the NSFC (51372095)the Program for JLU Science and Technology Innovative Research Team (JLUSTIRT)"Double-First Class" Discipline for Materials Science & Engineeringthe Special Funding for Academic Leaders~~
文摘Enabling the conversion of chemical energy of fuels directly into electricity without combustion,fuel cells are arousing great interest in both academia and industry.A typical case is the proton exchange membrane fuel cell(PEMFC),already commercialized by automobile giants.For mass popularization,however,three major criteria must be balanced:performance,durability and cost.The electrocatalysts used in both the anode and cathode are the kernel of PEMFCs,being essential for efficient operation.First in the firing‐line is the oxygen reduction reaction(ORR)at the cathode,which is normally very sluggish:over six orders of magnitude slower than the anode hydrogen oxidation reaction(HOR)[1].Thus,considerable efforts have been made to improve the cathode ORR.Identifying the main active sites is key to the design of optimum materials for enhanced ORR.Considering the complex balance of preparation,performance and cost,the active sites of metal‐nitrogen‐carbon(M‐N‐C)catalysts are particularly promising.Coupled with the single metal atom(SMA)catalysts[2–5],two excellent M‐N‐C catalysts were recently reported[6,7].New insights were thereby gained into the delicate architecture of carbon‐based SMA catalysts for ORR.
文摘39 mol% SiC of ceramic pellets ZrB<sub>2</sub>-αSiC and TiB<sub>2</sub>-αSiC were synthesized by the reactive hot pressure RHP process at 1850°C under 40 Mpa in vacuum. The XR diffraction displays the absence of other reagents apart from ZrB<sub>2</sub>, SiC and TiB<sub>2</sub> confirming the purity of the pellets. The cathodic exploitation of both of them through electrochemical study shows that TiB<sub>2</sub>-αSiC is the most active for Hydrogen Evolution Reaction (HER) and Hydrogen Oxidation Reaction (HOR) in 0.5 M of H<sub>2</sub>SO<sub>4</sub> solution at room temperature. Moreover, the kinetic exploitation shows that for both pellets the system is controlled by mass transport when they are used as HER. However, in the case of HOR, the system is controlled by the electron transfer.
基金The Top ten Technological Breakthrough Projects in Hunan Province(grant no.2023GK1050),the National Key R&D Program of China(grant no.2021YFA1500900)the National Natural Science Foundation of China(NSFC+9 种基金grant nos.22102053,21825201,22172047,and U19A2017)the Provincial Natural Science Foundation of Hunan,China(grant nos.2024JJ2012,2019GK2031,2016TP1009,2020JJ5045,and 2021JJ30089)the Science and Technology Innovation Program of Hunan Province,China(grant nos.2020RC2020 and 2022RC1036)Shenzhen Science and Technology Program,China(grant no.JCYJ20210324122209025)Changsha Municipal Natural Science Foundation,China(grant no.kq2007009)Changsha Municipal Natural Science Foundation,China(grant no.kq2007009)Basic and Applied Basic Research Foundation of Guangdong Province-Regional joint fund project,China(grant no.2021B1515120024)Guangdong Basic and Applied Basic Research Foundation,China(grant no.2024A1515012889)Shenzhen Science and Technology Program,China(grant no.JCYJ20210324122209025)Major Program of the Natural Science Foundation of Hunan Province,China(grant no.2021JC0006).
文摘Ruthenium(Ru)is a promising electrocatalyst for hydrogen oxidation reaction(HOR)due to the similar metal hydrogen bond energy to Pt.However,Ru is easily deactivated or dissolved under an oxidation potential,which makes it unavailable in proton exchange membrane fuel cells.In this work,ultrastable Ru-based electrocatalysts for HOR in high-temperature polymer electrolyte membrane fuel cells(HTPEMFCs)were developed by Mo doping.Under the operation conditions of HT-PEMFCs,thermal reduction inhibited the production of amorphous Ru oxide(RuO_(2))in the Ru-based electrocatalysts during the HOR.Mo doping significantly improved the stability of the electrocatalyst by decreasing the reduction temperature of RuO_(2)and accelerating the HOR by reducing the adsorption of H*.RuMo/C exhibited excellent HOR activity at high temperatures due to thermal reduction inhibition of electrooxidation;the fabricated HT-PEMFCs exhibited long-term stability and a 1050 mW cm^(−2)peak power density,comparable to the commercial Pt catalyst.This work provides a novel strategy for designing electrocatalysts by combining material intrinsic properties and work conditions,which could promote the development of advanced electrocatalysts for HT-PEMFCs.
文摘本文通过对众多最近才出版的非常重要的西藏医学文献的简要调查,探讨了西藏医学几个方面的问题。传统的西藏医学是本土的、印度的、汉地的和近东的有关身体和疾病、诊断学、治疗学理论的结合,但为什么印语的医学传统明显影响最大?萨霍尔之地,今天的孟加拉国,在它的构成中也发挥了作用,尽管作用小一些。本文作为明显是由一位萨霍尔国王所写的几个相对简要的医学教法的前言,同时也希冀能够为几位重要的西藏医生如宇妥·云丹衮布(12世纪早期)、拉杰·金巴·才旺(16世纪)和西藏医学章替派的一些成员提供更为充足的断代依据。最后,非常初步地、表面地调查了(一位)萨霍尔王直接或间接发挥作用的教法的论述,即《拳头十万》(Khu tshur’bum)和《十万拳头》(’Bum khu tshur),并厘定传记的细节,这些包括哈若恰(拉)杜,他的家族与异源教法文集有着密切的联系。
基金supported by the National Natural Science Foundation of China(Grant No.21771030)the Natural Science Foundation of Liaoning Province(2020-MS-113).
文摘Single-atom catalysts(SACs),which contain a single metal atom supported on a well-confined substrate,are among the most promising heterogeneous catalysts owing to their unique advantages,such as high intrinsic activity and selectivity,tunable bonds and coordination,abundant metal-containing active sites,and atomic economy.Since metal-support interactions(MSIs)in SACs exert a substantial influence on the catalytic properties,gaining a profound understanding and recognition of catalytic reactions depends greatly on investigating MSIs both experimentally and computationally.Hence,the engineer-ing and modulation of MSIs are regarded as one of the most efficient methods to rationally design SACs with disruptively enhanced catalytic properties.In this review,we track the recent advances in SACs from an MSI perspective.We then discuss the existing MSIs in SACs and elucidate the significant role of strong MSIs in catalytic properties and mechanisms.The chal-lenges hindering the rational design of supported SACs with strong MSIs,which are currently still far from being completely understood and overcome,are described.In addition,the correlation between strong MSIs and electrocatalytic activities in SACs,including an outlook to increase our understanding of MSIs,is discussed.Finally,the present review provides some perspectives and an in-depth understanding of strong MSIs to advance high-performing SACs.
基金support of this research by the National Natural Science Foundation of China(Nos.22179034 and 22279030)the Natural Science Foundation of Heilongjiang Province(No.ZD2023B002).
文摘To achieve the goals of the peak carbon dioxide emissions and carbon neutral,the development and utilization of sustainable clean energy are extremely important.Hydrogen fuel cells are an important system for converting hydrogen energy into electrical energy.However,the slow hydrogen oxidation reaction(HOR)kinetics under alkaline conditions has limited its development.Therefore,elucidating the catalytic mechanism of HOR in acidic and alkaline media is of great significance for the construction of highly active and stable catalysts.In terms of practicality,Pt is still the primary choice for commercialization of fuel cells.On the above basis,we first introduced the hydrogen binding energy theory and bifunctional theory used to describe the HOR activity,as well as the pH dependence.After that,the rational design strategies of Pt-based HOR catalysts were systematically classified and summarized from the perspective of activity descriptors.In addition,we further emphasized the importance of theoretical simulations and in situ characterization in revealing the HOR mechanism,which is crucial for the rational design of catalysts.Moreover,the practical application of Pt-based HOR catalysts in fuel cells was also presented.In closing,the current challenges and future development directions of HOR catalysts were discussed.This review will provide a deep understanding for exploring the mechanism of highly efficient HOR catalysts and the development of fuel cells.
基金The study was financially supported by the European Union(ERDF),“Region Nouvelle Aquitaine”.
文摘In this paper the electrochemical properties of some platinum-based nanoalloys are reviewed.The revision is centered on electrocatalytic materials generated via the carbonyl chemical route(CCR).In considering the effects of segregation in these bimetals,the reaction of the hydrogen oxidation(HOR)and oxygen reduction(ORR)in the alkaline medium was investigated.The reaction kinetics of these electrochemical processes in the alkaline electrolyte is still a challenge.For the design of high-performance platinum-based electrocatalysts,it is of importance to know that the kinetics of HOR and ORR also depends on the Pt adsorbate.The electrochemical analysis,based on the study of Pt nanoalloyed surfaces with different Pt-adsorbate interactions,was taken into account.A clear trend in the HOR as well as the ORR activity,in the alkaline electrolyte,was established,revealing that the activity changes in the order PtSn/C<PtCr/C<Pt/C(JM)<PtCo/C<PtNi/C for the former,and for the latter Pt/C(Tek)<Pt/C(JM)<PtCr/C<PtNi/C.The decisive effect of the Pt-H_(ad)energy on the HOR kinetics on Pt surfaces apparently depends on the oxophilicity role of the metal to favor M-OH_(ad).The apparent electronic effect is not evident on these materials,except if a strong metal interaction is induced per se with either the carbon or oxide supports,e.g.,the Pt/SnO_(2)-C interface in acidic media.Favorable effects of Pt-H_(ad)energy on HOR kinetics were found with the oxophilicity of the sp^(2)domains of carbon that serve as anchoring or nucleation sites for platinum atoms.These results were compared with the literature data,and it turns out that this type of strong metal support interaction(SMSI)modification is favorably induced by UV–VIS irradiation and outperforms Pt-Mmaterials to some extent.Either for HOR or ORR,it is shown that non-noble metals not only act as a surrogate metal for Pt utilization by inducing a compressive stress effect between the Pt atoms in the outermost layer but also participate in the electrocatalytic reaction.This information is important to understand and develop structures with the Pt/C catalyst for the manufacture of electrode materials in the alkaline medium.
