The epitaxial heterostructure can be rationally designed based on the in situ growth of two compatible phases with lattice similarity,in which the modulated electronic states and tuned adsorption behaviors are conduci...The epitaxial heterostructure can be rationally designed based on the in situ growth of two compatible phases with lattice similarity,in which the modulated electronic states and tuned adsorption behaviors are conducive to the enhancement of electrocatalytic activity.Herein,theoretical simulations first disclose the charge transfer trend and reinforced inherent electron conduction around the epitaxial heterointerface between Ru clusters and Ni_(3)N substrate(cRu-Ni_(3)N),thus leading to the optimized adsorption behaviors and reduced activation energy barriers.Subsequently,the defectrich nanosheets with the epitaxially grown cRu-Ni_(3)N heterointerface are successfully constructed.Impressively,by virtue of the superiority of intrinsic activity and reaction kinetics,such unique epitaxial heterostructure exhibits remarkable bifunctional catalytic activity toward electrocatalytic OER(226 mV@20 mA cm^(−2))and HER(32 mV@10 mA cm^(−2))in alkaline media.Furthermore,it also shows great application prospect in alkaline freshwater and seawater splitting,as well as solar-to-hydrogen integrated system.This work could provide beneficial enlightenment for the establishment of advanced electrocatalysts with epitaxial heterointerfaces.展开更多
过渡金属电催化剂因其优良的电催化性能、低廉的成本,以及在电解水、燃料电池、锌空电池等领域展现出极大的应用潜力,逐渐成为人们的研究热点。其中,过渡金属氮化物(Transition Metal Nitrides,TMNs)因氮化过程能使金属的d带收缩变窄,...过渡金属电催化剂因其优良的电催化性能、低廉的成本,以及在电解水、燃料电池、锌空电池等领域展现出极大的应用潜力,逐渐成为人们的研究热点。其中,过渡金属氮化物(Transition Metal Nitrides,TMNs)因氮化过程能使金属的d带收缩变窄,填充态发生改变,从而调节金属-氢的键能,达到提高导电性及催化活性的目的,近来备受学者们的关注。因此,本文综述了TMNs纳米电催化剂的最新研究进展,包括借助d带理论讨论了氮元素对其结构及活性的影响;评述了TMNs的物理、化学等合成方法及掺杂、复合等改性方法;列举了其在析氢反应、析氧反应、氧还原反应等电催化领域中的重要应用;最后,指出了TMNs在现阶段所面临的挑战和问题,并对其今后发展作出展望。展开更多
Hydrogen,a renewable and outstanding energy carrier with zero carbon dioxide emission,is regarded as the best alternative to fossil fuels.The most preferred route to large-scale production of hydrogen is by water elec...Hydrogen,a renewable and outstanding energy carrier with zero carbon dioxide emission,is regarded as the best alternative to fossil fuels.The most preferred route to large-scale production of hydrogen is by water electrolysis from the intermittent sources(e.g.,wind,solar,hydro,and tidal energy).However,the efficiency of water electrolysis is very much dependent on the activity of electrocatalysts.Thus,designing high-effective,stable,and cheap materials for hydrogen evolution reaction(HER)could have a substantial impact on renewable energy technologies.Recently,single-atom catalysts(SACs)have emerged as a new frontier in catalysis science,because SACs have maximum atom-utilization efficiency and excellent catalytic reaction activity.Various synthesis methods and analytical techniques have been adopted to prepare and characterize these SACs.In this review,we discuss recent progress on SACs synthesis,characterization methods,and their catalytic applications.Particularly,we highlight their unique electrochemical characteristics toward HER.Finally,the current key challenges in SACs for HER are pointed out and some potential directions are proposed as well.展开更多
In this article, we study positive solutions to the system{Aαu（x） = Cn,αPV∫Rn（a1（x-y）（u（x）-u（y）））/（｜x-y｜n＋α）dy = f（u（x）, Bβv（x） = Cn,βPV ∫Rn（a2（x-y）（v（x）-v（y））/（｜x-y｜n＋β）dy ...In this article, we study positive solutions to the system{Aαu（x） = Cn,αPV∫Rn（a1（x-y）（u（x）-u（y）））/（｜x-y｜n＋α）dy = f（u（x）, Bβv（x） = Cn,βPV ∫Rn（a2（x-y）（v（x）-v（y））/（｜x-y｜n＋β）dy = g（u（x）,v（x））.To reach our aim, by using the method of moving planes, we prove a narrow region principle and a decay at infinity by the iteration method. On the basis of these results, we conclude radial symmetry and monotonicity of positive solutions for the problems involving the weighted fractional system on an unit ball and the whole space. Furthermore, non-existence of nonnegative solutions on a half space is given.展开更多
In this paper,we prove the existence of positive solutions to the following weighted fractional system involving distinct weighted fractional Laplacians with gradient terms:{(−Δ)_(a/1)^(α/2)u1(x)=u_(1)^(q11)(x)+u_(2...In this paper,we prove the existence of positive solutions to the following weighted fractional system involving distinct weighted fractional Laplacians with gradient terms:{(−Δ)_(a/1)^(α/2)u1(x)=u_(1)^(q11)(x)+u_(2)^(q12)(x)+h_(1)(x,u_(1)(x),u_(2)(x),∇u_(1)(x),∇u_(2)(x)),x∈Ω,(−Δ)_(a2)^(β/2)u2(x)=u_(1)^(q21)(x)+u_(2)^(q22)(x)+h_(2)(x,u_(1)(x),u_(2)(x),∇u_(1)(x),∇u_(2)(x)),x∈Ω,u_(1)(x)=0,u_(2)(x)=0,x∈R^(n)∖Ω.Here(−Δ)_(a1)^(α/2) and(−Δ)_(a2)^(β/2) denote weighted fractional Laplacians andΩ⊂R^(n) is a C^(2) bounded domain.It is shown that under some assumptions on h_(i)(i=1,2),the problem admits at least one positive solution(u_(1)(x),u_(2)(x)).We first obtain the{a priori}bounds of solutions to the system by using the direct blow-up method of Chen,Li and Li.Then the proof of existence is based on a topological degree theory.展开更多
Designing synergistic heterogeneous catalytic interfaces is the key to developing highly compatible pH-universal electrocatalysts for complex chemical environments.Our theoretical calculation results demonstrate that ...Designing synergistic heterogeneous catalytic interfaces is the key to developing highly compatible pH-universal electrocatalysts for complex chemical environments.Our theoretical calculation results demonstrate that the Ru-Ru2P heterointerface can not only promote the redistribution of charges,but also reduce the d-band center,and then enhances the adsorption capacity of the key intermediate.However,in situ and facile synthesis of Ru-Ru2P heterostructures is severely limited by thermodynamic obstacles.Herein,we propose a molten salt-assisted catalytic synthesis scheme,and successfully build a series of homologous metallic Ru-Ru2P heterostructure catalysts with different molar ratios of Ru to P under atmospheric pressure and low-temperature(400C).The resultant Ru-Ru2P with rich heterostructures show the Pt-like HER performance in different pH media.Particularly,it is prominent under alkaline conditions(18 mV@10 mA cm^(2)),which outperforms the Pt catalyst(37 mV@10 mA cm^(2)).Furthermore,Ru-Ru2P heterostructures also show certain potential in the electrolysis of seawater to produce hydrogen.This work represents a significant supplement of high-efficiency pH-universal HER catalysts,and provides a new light on interface engineering in energy technology fields and beyond.展开更多
The Democratic Republic of Congo (DRC) is suffering from the world’s second largest and most prolonged Ebola virus disease (EVD) epidemic on record (Figure 1). The current prevalence of EVD in the DRC makes this the ...The Democratic Republic of Congo (DRC) is suffering from the world’s second largest and most prolonged Ebola virus disease (EVD) epidemic on record (Figure 1). The current prevalence of EVD in the DRC makes this the 10th (and largest) EVD epidemic in the DRC since the first discovery of the Zaire Ebola virus in 1976 (Ilunga Kalenga, 2019).Globally, it is the second worst outbreak in the history of Ebola epidemics.展开更多
Designing hierarchical heterostructure to optimize the adsorption of hydrogen intermediate(H*)is impressive for hydrogen evolution reaction(HER)catalysis.Herein,we show that vertically mounting two-dimensional(2D)laye...Designing hierarchical heterostructure to optimize the adsorption of hydrogen intermediate(H*)is impressive for hydrogen evolution reaction(HER)catalysis.Herein,we show that vertically mounting two-dimensional(2D)layered molybdenum disulfide(MoS_(2))nanosheets on 2D nonlayered dimolybdenum carbide(Mo_(2)C)nanomeshes to form a hierarchical heterostructure largely accelerates the HER kinetics in acidic electrolyte due to the weakening adsorption strength of H*on 2D Mo_(2)C nanomeshes.Our hierarchical MoS2/Mo2C heterostructure therefore gives a decrease of overpotential for up to 500 mV at-10 mA·cm^(-2)and an almost 200-fold higher kinetics current density compared with the pristine Mo2C nanomeshes and maintains robust stability with a small drop of overpotential for only 16 mV upon 5,000 cycles.We further rationalize this finding by theoretical calculations and find an optimized adsorption free energy of H*,identifying that the MoS_(2)featuring strong H*desorption plays a key role in weakening the strong binding of Mo_(2)C with H*and therefore improves the intrinsic HER activity on active C sites of Mo_(2)C.This present finding shines the light on the rational design of heterostructured catalysts with synergistic geometry.展开更多
基金financially sponsored by the National Natural Science Foundation of China(Grant No.22075223,22179104)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology)(2021-ZD-4)the Fundamental Research Funds for the Central Universities(No.2020-YB-012)。
文摘The epitaxial heterostructure can be rationally designed based on the in situ growth of two compatible phases with lattice similarity,in which the modulated electronic states and tuned adsorption behaviors are conducive to the enhancement of electrocatalytic activity.Herein,theoretical simulations first disclose the charge transfer trend and reinforced inherent electron conduction around the epitaxial heterointerface between Ru clusters and Ni_(3)N substrate(cRu-Ni_(3)N),thus leading to the optimized adsorption behaviors and reduced activation energy barriers.Subsequently,the defectrich nanosheets with the epitaxially grown cRu-Ni_(3)N heterointerface are successfully constructed.Impressively,by virtue of the superiority of intrinsic activity and reaction kinetics,such unique epitaxial heterostructure exhibits remarkable bifunctional catalytic activity toward electrocatalytic OER(226 mV@20 mA cm^(−2))and HER(32 mV@10 mA cm^(−2))in alkaline media.Furthermore,it also shows great application prospect in alkaline freshwater and seawater splitting,as well as solar-to-hydrogen integrated system.This work could provide beneficial enlightenment for the establishment of advanced electrocatalysts with epitaxial heterointerfaces.
文摘过渡金属电催化剂因其优良的电催化性能、低廉的成本,以及在电解水、燃料电池、锌空电池等领域展现出极大的应用潜力,逐渐成为人们的研究热点。其中,过渡金属氮化物(Transition Metal Nitrides,TMNs)因氮化过程能使金属的d带收缩变窄,填充态发生改变,从而调节金属-氢的键能,达到提高导电性及催化活性的目的,近来备受学者们的关注。因此,本文综述了TMNs纳米电催化剂的最新研究进展,包括借助d带理论讨论了氮元素对其结构及活性的影响;评述了TMNs的物理、化学等合成方法及掺杂、复合等改性方法;列举了其在析氢反应、析氧反应、氧还原反应等电催化领域中的重要应用;最后,指出了TMNs在现阶段所面临的挑战和问题,并对其今后发展作出展望。
基金financially supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)Institut National de la Recherche Scientifique(INRS)the National Natural Science Foundation of China(516722040)
文摘Hydrogen,a renewable and outstanding energy carrier with zero carbon dioxide emission,is regarded as the best alternative to fossil fuels.The most preferred route to large-scale production of hydrogen is by water electrolysis from the intermittent sources(e.g.,wind,solar,hydro,and tidal energy).However,the efficiency of water electrolysis is very much dependent on the activity of electrocatalysts.Thus,designing high-effective,stable,and cheap materials for hydrogen evolution reaction(HER)could have a substantial impact on renewable energy technologies.Recently,single-atom catalysts(SACs)have emerged as a new frontier in catalysis science,because SACs have maximum atom-utilization efficiency and excellent catalytic reaction activity.Various synthesis methods and analytical techniques have been adopted to prepare and characterize these SACs.In this review,we discuss recent progress on SACs synthesis,characterization methods,and their catalytic applications.Particularly,we highlight their unique electrochemical characteristics toward HER.Finally,the current key challenges in SACs for HER are pointed out and some potential directions are proposed as well.
基金Supported by National Natural Science Foundation of China(11771354)
文摘In this article, we study positive solutions to the system{Aαu（x） = Cn,αPV∫Rn（a1（x-y）（u（x）-u（y）））/（｜x-y｜n＋α）dy = f（u（x）, Bβv（x） = Cn,βPV ∫Rn（a2（x-y）（v（x）-v（y））/（｜x-y｜n＋β）dy = g（u（x）,v（x））.To reach our aim, by using the method of moving planes, we prove a narrow region principle and a decay at infinity by the iteration method. On the basis of these results, we conclude radial symmetry and monotonicity of positive solutions for the problems involving the weighted fractional system on an unit ball and the whole space. Furthermore, non-existence of nonnegative solutions on a half space is given.
文摘In this paper,we prove the existence of positive solutions to the following weighted fractional system involving distinct weighted fractional Laplacians with gradient terms:{(−Δ)_(a/1)^(α/2)u1(x)=u_(1)^(q11)(x)+u_(2)^(q12)(x)+h_(1)(x,u_(1)(x),u_(2)(x),∇u_(1)(x),∇u_(2)(x)),x∈Ω,(−Δ)_(a2)^(β/2)u2(x)=u_(1)^(q21)(x)+u_(2)^(q22)(x)+h_(2)(x,u_(1)(x),u_(2)(x),∇u_(1)(x),∇u_(2)(x)),x∈Ω,u_(1)(x)=0,u_(2)(x)=0,x∈R^(n)∖Ω.Here(−Δ)_(a1)^(α/2) and(−Δ)_(a2)^(β/2) denote weighted fractional Laplacians andΩ⊂R^(n) is a C^(2) bounded domain.It is shown that under some assumptions on h_(i)(i=1,2),the problem admits at least one positive solution(u_(1)(x),u_(2)(x)).We first obtain the{a priori}bounds of solutions to the system by using the direct blow-up method of Chen,Li and Li.Then the proof of existence is based on a topological degree theory.
基金National Natural Science Foundation of China,Grant/Award Numbers:22075223,22179104State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology),Grant/Award Number:2021-ZD-4。
文摘Designing synergistic heterogeneous catalytic interfaces is the key to developing highly compatible pH-universal electrocatalysts for complex chemical environments.Our theoretical calculation results demonstrate that the Ru-Ru2P heterointerface can not only promote the redistribution of charges,but also reduce the d-band center,and then enhances the adsorption capacity of the key intermediate.However,in situ and facile synthesis of Ru-Ru2P heterostructures is severely limited by thermodynamic obstacles.Herein,we propose a molten salt-assisted catalytic synthesis scheme,and successfully build a series of homologous metallic Ru-Ru2P heterostructure catalysts with different molar ratios of Ru to P under atmospheric pressure and low-temperature(400C).The resultant Ru-Ru2P with rich heterostructures show the Pt-like HER performance in different pH media.Particularly,it is prominent under alkaline conditions(18 mV@10 mA cm^(2)),which outperforms the Pt catalyst(37 mV@10 mA cm^(2)).Furthermore,Ru-Ru2P heterostructures also show certain potential in the electrolysis of seawater to produce hydrogen.This work represents a significant supplement of high-efficiency pH-universal HER catalysts,and provides a new light on interface engineering in energy technology fields and beyond.
文摘The Democratic Republic of Congo (DRC) is suffering from the world’s second largest and most prolonged Ebola virus disease (EVD) epidemic on record (Figure 1). The current prevalence of EVD in the DRC makes this the 10th (and largest) EVD epidemic in the DRC since the first discovery of the Zaire Ebola virus in 1976 (Ilunga Kalenga, 2019).Globally, it is the second worst outbreak in the history of Ebola epidemics.
基金The authors thank the supports from the Fundamental Research Funds for the Central Universities(No.40120631)the Zhejiang Provincial Natural Science Foundation(Nos.LQ22B060003 and LY20E020004)+1 种基金the Fundamental Research Funds for the Provincial Universities of Zhejiang(No.2020YQ005)the Research Foundation of Talented Scholars of Zhejiang A&F University(No.2020FR069).
文摘Designing hierarchical heterostructure to optimize the adsorption of hydrogen intermediate(H*)is impressive for hydrogen evolution reaction(HER)catalysis.Herein,we show that vertically mounting two-dimensional(2D)layered molybdenum disulfide(MoS_(2))nanosheets on 2D nonlayered dimolybdenum carbide(Mo_(2)C)nanomeshes to form a hierarchical heterostructure largely accelerates the HER kinetics in acidic electrolyte due to the weakening adsorption strength of H*on 2D Mo_(2)C nanomeshes.Our hierarchical MoS2/Mo2C heterostructure therefore gives a decrease of overpotential for up to 500 mV at-10 mA·cm^(-2)and an almost 200-fold higher kinetics current density compared with the pristine Mo2C nanomeshes and maintains robust stability with a small drop of overpotential for only 16 mV upon 5,000 cycles.We further rationalize this finding by theoretical calculations and find an optimized adsorption free energy of H*,identifying that the MoS_(2)featuring strong H*desorption plays a key role in weakening the strong binding of Mo_(2)C with H*and therefore improves the intrinsic HER activity on active C sites of Mo_(2)C.This present finding shines the light on the rational design of heterostructured catalysts with synergistic geometry.
