Nanocarbons are of progressively increasing importance in energy electrocatalysis, including oxygen reduction, oxygen evolution, hydrogen evolution, COreduction, etc. Precious-metal-free or metal-free nanocarbon-based...Nanocarbons are of progressively increasing importance in energy electrocatalysis, including oxygen reduction, oxygen evolution, hydrogen evolution, COreduction, etc. Precious-metal-free or metal-free nanocarbon-based electrocatalysts have been revealed to potentially have effective activity and remarkable durability, which is promising to replace precious metals in some important energy technologies,such as fuel cells, metal–air batteries, and water splitting. In this review, rather than overviewing recent progress completely, we aim to give an in-depth digestion of present achievements, focusing on the different roles of nanocarbons and material design principles. The multifunctionalities of nanocarbon substrates(accelerating the electron and mass transport, regulating the incorporation of active components,manipulating electron structures, generating confinement effects, assembly into 3 D free-standing electrodes) and the intrinsic activity of nanocarbon catalysts(multi-heteroatom doping, hierarchical structure,topological defects) are discussed systematically, with perspectives on the further research in this rising research field. This review is inspiring for more insights and methodical research in mechanism understanding, material design, and device optimization, leading to a targeted and high-efficiency development of energy electrocatalysis.展开更多
The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water sp...The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water splitting cells. Layered double hydroxides(LDHs) and their derivatives(e.g., transition metal alloys, oxides, sulfides, nitrides and phosphides) have been adopted as catalysts for various electrochemical reactions, such as oxygen reduction, oxygen evolution, hydrogen evolution, and COreduction, which show excellent activity and remarkable durability in electrocatalytic process. In this review, the synthesis strategies, structural characters and electrochemical performances for the LDHs and their derivatives are described. In addition, we also discussed the effect of electronic and geometry structures to their electrocatalytic activity. The further development of high-performance electrocatalysts based on LDHs and their derivatives is covered by both a short summary and future outlook from the viewpoint of the material design and practical application.展开更多
Hetero-structure induced high performance catalyst for oxygen evolution reaction(OER)in the water splitting reaction has received increased attention.Herein,we demonstrated a novel catalyst system of NiSe_(2)-CoSe_(2)...Hetero-structure induced high performance catalyst for oxygen evolution reaction(OER)in the water splitting reaction has received increased attention.Herein,we demonstrated a novel catalyst system of NiSe_(2)-CoSe_(2) consisting of nanorods and nanoparticles for the efficient OER in the alkaline electrolyte.This catalyst system can be easily fabricated via a low-temperature selenization of the solvothermal synthesized NiCo(OH)x precursor and the unique morphology of hybrid nanorods and nanoparticles was found by the electron microscopy analysis.The high valence state of the metal species was indicated by X-ray photoelectron spectroscopy study and a strong electronic effect was found in the NiSe_(2)-CoSe_(2) catalyst system compared to their counterparts.As a result,NiSe_(2)-CoSe_(2) exhibited high catalytic performance with a low overpotential of 250 mV to reach 10 mA·cm^(-2) for OER in the alkaline solution.Furthermore,high catalytic stability and catalytic kinetics were also observed.The superior performance can be attributed to the high valence states of Ni and Co and their strong synergetic coupling effect between the nanorods and nanoparticles,which could accelerate the charge transfer and offer abundant electrocatalytic active sites.The current work offers an efficient hetero-structure catalyst system for OER,and the results are helpful for the catalysis understanding.展开更多
Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and ...Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and low intrinsic activity limit their practical application.To date,improvement of the intrinsic activity and stability of NiFe-LDHs through the introduction of heteroatoms or its combination with other conductive substrates to enhance their water-splitting performance has drawn increasing attention.In this study,vertically interlaced ternary phosphatised nickel/iron hybrids grown on the surface of titanium carbide flakes(NiFe P/MXene)were successfully synthesised through a hydrothermal reaction and phosphating calcination process.The optimised NiFe P/MXene exhibited a low overpotential of 286 m V at 10 m A cm^(-2) and a Tafel slope of 35 m V dec^(-1) for the OER,which exceeded the performance of several existing NiFe-based catalysts.NiFe P/MXene was further used as a water-splitting anode in an alkaline electrolyte,exhibiting a cell voltage of only 1.61 V to achieve a current density of 10 m A cm^(-2).Density functional theory(DFT)calculations revealed that the combination of MXene acting as a conductive substrate and the phosphating process can effectively tune the electronic structure and density of the electrocatalyst surface to promote the energy level of the d-band centre,resulting in an enhanced OER performance.This study provides a valuable guideline for designing high-performance MXenesupported NiFe-based OER catalysts.展开更多
This work unraveled the synergistic effects of crystal structure and oxygen vacancy on the photocatalytic activity of Bi2O3 polymorphs at an atomic level for the first time. The artificial oxygen vacancy is introduced...This work unraveled the synergistic effects of crystal structure and oxygen vacancy on the photocatalytic activity of Bi2O3 polymorphs at an atomic level for the first time. The artificial oxygen vacancy is introduced into α-Bi2O3 and β-Bi2O3 via a facile method to engineer the band structures and transportation of carriers and redox reaction for highly enhanced photocatalysis. After the optimization, the photocatalytic NO removal ratio on defective β-Bi2O3 was increased from 25.2% to 52.0% under visible light irradiation.On defective a-Bi2O3, the NO removal ratio is just increased from 7.3% to 20.1%. The difference in the activity enhancement is associated with the different structure of crystal phase and oxygen vacancy.The density functional theory(DFT) calculation and experimental results confirm that the oxygen vacancy in a-Bi2O3 and β-Bi2O3 could promote the activation of reactants and intermediate as active centers. The crystal structure and oxygen vacancy could synergistically regulate the electrons transfer pathway. On defective β-Bi2O3 with tunnel structure, the reactants activation and charge transfer were more efficient than that on α-Bi2O3 with zigzag-type configuration because the defect structures on the surface of a-Bi2O3 and β-Bi2O3 were different. Moreover, the in situ FT-IR revealed the mechanisms of photocatalytic NO oxidation. The photocatalytic NO conversion pathway on α-Bi2O3 and β-Bi2O3 can be tuned by the different surface defect structures. This work could provide a novel strategy to regulate the photocatalytic activity and conversion pathway via the synergistic effects of crystal structure and oxygen vacancy.展开更多
Gaining insight into the structure evolution of transition-metal phosphides during anodic oxidation is significant to understand their oxygen evolution reaction(OER) mechanism, and then design highefficiency transitio...Gaining insight into the structure evolution of transition-metal phosphides during anodic oxidation is significant to understand their oxygen evolution reaction(OER) mechanism, and then design highefficiency transition metal-based catalysts. Herein, NiCo_2P_x nanowires(NWs) vertically grown on Ni foam were adopted as the target to explore the in-situ morphology and chemical component reconstitution during the anodic oxidation. The major factors causing the transformation from NiCo_2P_x into the hierarchical NiCo_2P_x@CoNi(OOH)_x NWs are two competing reactions: the dissolution of NiCo_2P_x NWs and the oxidative re-deposition of dissolved Co^(2+) and Ni^(2+) ions, which is based primarily on the anodic bias applied on NiCo2 Px NWs. The well balance of above competing reactions, and local pH on the surface of NiCo_2P_x NW modulated by the anodic oxidation can serve to control the anodic electrodeposition and rearrangement of metal ions on the surface of NiCo_2P_x NWs, and the immediate conversion into CoNi(OOH)_x. Consequently, the regular hexagonal CoNi(OOH)_x nanosheets grew around NiCo_2P_x NWs.Benefiting from the active catalytic sites on the surface and the sufficient conductivity, the resultant NiCo_2P_x@CoNi(OOH)_x arrays also display good OER activity, in terms of the fast kinetics process, the high energy conversion efficiency, especially the excellent durability. The strategy of in-situ structure reconstitution by electrochemical reaction described here offers a reliable and valid way to construct the highly active systems for various electrocatalytic applications.展开更多
Oxygen,iron,and polyunsaturated fatty acids(PUFAs;fatty acids containing more than one double bond)are all beneficial to our cellular lives.Incorporation of these components into cellular processes,however,comes at a ...Oxygen,iron,and polyunsaturated fatty acids(PUFAs;fatty acids containing more than one double bond)are all beneficial to our cellular lives.Incorporation of these components into cellular processes,however,comes at a cost:the bis-allylic structure of PUFAs and the enrichment of cellular environments with iron and oxygen render PUFA-containing phospholipids(PUFA-PLs)particularly susceptible to peroxidation(Yang and Stockwell,2016).展开更多
Air cathode performance is essential for rechargeable zinc–air batteries(ZABs).In this study,we develop a self-templated synthesis technique for fabricating bimetallic alloys(FeNi_(3)),bimetallic nitrides(FeNi_(3)N)a...Air cathode performance is essential for rechargeable zinc–air batteries(ZABs).In this study,we develop a self-templated synthesis technique for fabricating bimetallic alloys(FeNi_(3)),bimetallic nitrides(FeNi_(3)N)and heterostructured FeNi_(3)/FeNi_(3)N hollow nanotubes.Owing to its structural and compositional advantages,FeNi_(3)/FeNi_(3)N exhibits remarkable bifunctional oxygen electrocatalytic performance with an extremely small potential gap of 0.68V between the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR).Theoretical calculations reveal reduced Gibbs free energy for the rate-limiting O–O bond formation during OER due to the self-adaptive surface reconfiguration,which induces a synergistic effect between Fe(Ni)OOH developed in situ on the surface and the inner FeNi_(3)/FeNi_(3)N.ZAB fabricated using the FeNi_(3)/FeNi_(3)N catalyst shows high power density,small charge/discharge voltage gap and excellent cycling stability.In addition to its excellent battery performance,the corresponding quasi-solid-state ZAB shows robust flexibility and integrability.The synthesis method is extended to prepare a CoFe/CoFeN oxygen electrocatalyst,demonstrating its applicability to other iron-group elements.展开更多
Water-based rechargeable metal-air batteries play an important role in the storage and conversion of renewable electric energy.However,the sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution re...Water-based rechargeable metal-air batteries play an important role in the storage and conversion of renewable electric energy.However,the sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have limited the practical application of rechargeable metal-air batteries.Most of reviews were focused on single functional electrocatalysts while few on bifunctional electrocatalysts.It is indispensable but challenging to design a bifunctional electrocatalyst that is active and stable to the two reactions.Recently,attempts to develop high active bifunctional electrocatalysts for both ORR and OER increase rapidly.Much work is focused on the micro-nano design of advanced structures to improve the performance of bifunctional electrocatalyst.Transition-metal materials,carbon materials and composite materials,and the methods developed to prepare micro-nano structures,such as electrochemical methods,chemical vapor deposition,hydrothermal methods and template methods are reported in literatures.Additionally,many strategies,such as adjustments of electronic structures,oxygen defects,metal-oxygen bonds,interfacial strain,nano composites,heteroatom doping etc.,have been used extensively to design bifunctional electrocatalysts.To well understand the achievements in the recent literatures,this review focuses on the micro-nano structural design of materials,and the related methods and strategies are classed into two groups for the improvement of intrinsic and apparent activities.The fine adjustment of nano structures and an in-depth understanding of the reaction mechanism are also discussed briefly.展开更多
基金supported by the National Key Research and Development Program (Nos. 2016YFA0202500 and 2016YFA0200102)the Natural Scientific Foundation of China (No. 21561130151)Royal Society for the award of a Newton Advanced Fellowship (Ref: NA140249)
文摘Nanocarbons are of progressively increasing importance in energy electrocatalysis, including oxygen reduction, oxygen evolution, hydrogen evolution, COreduction, etc. Precious-metal-free or metal-free nanocarbon-based electrocatalysts have been revealed to potentially have effective activity and remarkable durability, which is promising to replace precious metals in some important energy technologies,such as fuel cells, metal–air batteries, and water splitting. In this review, rather than overviewing recent progress completely, we aim to give an in-depth digestion of present achievements, focusing on the different roles of nanocarbons and material design principles. The multifunctionalities of nanocarbon substrates(accelerating the electron and mass transport, regulating the incorporation of active components,manipulating electron structures, generating confinement effects, assembly into 3 D free-standing electrodes) and the intrinsic activity of nanocarbon catalysts(multi-heteroatom doping, hierarchical structure,topological defects) are discussed systematically, with perspectives on the further research in this rising research field. This review is inspiring for more insights and methodical research in mechanism understanding, material design, and device optimization, leading to a targeted and high-efficiency development of energy electrocatalysis.
基金supported by the National Natural Science Foundation of China(Nos.U146211821601011)+2 种基金the 973 Program(Grant No.2014CB932102)the Fundamental Research Funds for the Central Universities(buctrc201506PYCC1704)
文摘The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water splitting cells. Layered double hydroxides(LDHs) and their derivatives(e.g., transition metal alloys, oxides, sulfides, nitrides and phosphides) have been adopted as catalysts for various electrochemical reactions, such as oxygen reduction, oxygen evolution, hydrogen evolution, and COreduction, which show excellent activity and remarkable durability in electrocatalytic process. In this review, the synthesis strategies, structural characters and electrochemical performances for the LDHs and their derivatives are described. In addition, we also discussed the effect of electronic and geometry structures to their electrocatalytic activity. The further development of high-performance electrocatalysts based on LDHs and their derivatives is covered by both a short summary and future outlook from the viewpoint of the material design and practical application.
基金The work is supported by the National Natural Science Foundation of China(21972124)the Priority Academic Program Development of Jiangsu Higher Education Institution.the support of the Six Talent Peaks Project of Jiangsu Province(XCL-070-2018)。
文摘Hetero-structure induced high performance catalyst for oxygen evolution reaction(OER)in the water splitting reaction has received increased attention.Herein,we demonstrated a novel catalyst system of NiSe_(2)-CoSe_(2) consisting of nanorods and nanoparticles for the efficient OER in the alkaline electrolyte.This catalyst system can be easily fabricated via a low-temperature selenization of the solvothermal synthesized NiCo(OH)x precursor and the unique morphology of hybrid nanorods and nanoparticles was found by the electron microscopy analysis.The high valence state of the metal species was indicated by X-ray photoelectron spectroscopy study and a strong electronic effect was found in the NiSe_(2)-CoSe_(2) catalyst system compared to their counterparts.As a result,NiSe_(2)-CoSe_(2) exhibited high catalytic performance with a low overpotential of 250 mV to reach 10 mA·cm^(-2) for OER in the alkaline solution.Furthermore,high catalytic stability and catalytic kinetics were also observed.The superior performance can be attributed to the high valence states of Ni and Co and their strong synergetic coupling effect between the nanorods and nanoparticles,which could accelerate the charge transfer and offer abundant electrocatalytic active sites.The current work offers an efficient hetero-structure catalyst system for OER,and the results are helpful for the catalysis understanding.
基金supported by the National Natural Science Foundation of China(21875048)the Outstanding Youth Project of Guangdong Natural Science Foundation(2020B1515020028)+1 种基金the Yangcheng Scholars Research Project of Guangzhou(201831820)the Science and Technology Research Project of Guangzhou(202002010007)。
文摘Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and low intrinsic activity limit their practical application.To date,improvement of the intrinsic activity and stability of NiFe-LDHs through the introduction of heteroatoms or its combination with other conductive substrates to enhance their water-splitting performance has drawn increasing attention.In this study,vertically interlaced ternary phosphatised nickel/iron hybrids grown on the surface of titanium carbide flakes(NiFe P/MXene)were successfully synthesised through a hydrothermal reaction and phosphating calcination process.The optimised NiFe P/MXene exhibited a low overpotential of 286 m V at 10 m A cm^(-2) and a Tafel slope of 35 m V dec^(-1) for the OER,which exceeded the performance of several existing NiFe-based catalysts.NiFe P/MXene was further used as a water-splitting anode in an alkaline electrolyte,exhibiting a cell voltage of only 1.61 V to achieve a current density of 10 m A cm^(-2).Density functional theory(DFT)calculations revealed that the combination of MXene acting as a conductive substrate and the phosphating process can effectively tune the electronic structure and density of the electrocatalyst surface to promote the energy level of the d-band centre,resulting in an enhanced OER performance.This study provides a valuable guideline for designing high-performance MXenesupported NiFe-based OER catalysts.
基金supported by the National Natural Science Foundation of China (21822601, 21777011, and 21501016)the Innovative Research Team of Chongqing (CXQT19023)+2 种基金the Natural Science Foundation of Chongqing (cstc2017jcyj BX0052)the Plan for “National Youth Talents” of the Organization Department of the Central Committee, the Innovative Project from Chongqing Technology and Business University (yjscxx2019-101-67)the Fundamental Research Funds for the Central Universities (ZYGX2019Z021)。
文摘This work unraveled the synergistic effects of crystal structure and oxygen vacancy on the photocatalytic activity of Bi2O3 polymorphs at an atomic level for the first time. The artificial oxygen vacancy is introduced into α-Bi2O3 and β-Bi2O3 via a facile method to engineer the band structures and transportation of carriers and redox reaction for highly enhanced photocatalysis. After the optimization, the photocatalytic NO removal ratio on defective β-Bi2O3 was increased from 25.2% to 52.0% under visible light irradiation.On defective a-Bi2O3, the NO removal ratio is just increased from 7.3% to 20.1%. The difference in the activity enhancement is associated with the different structure of crystal phase and oxygen vacancy.The density functional theory(DFT) calculation and experimental results confirm that the oxygen vacancy in a-Bi2O3 and β-Bi2O3 could promote the activation of reactants and intermediate as active centers. The crystal structure and oxygen vacancy could synergistically regulate the electrons transfer pathway. On defective β-Bi2O3 with tunnel structure, the reactants activation and charge transfer were more efficient than that on α-Bi2O3 with zigzag-type configuration because the defect structures on the surface of a-Bi2O3 and β-Bi2O3 were different. Moreover, the in situ FT-IR revealed the mechanisms of photocatalytic NO oxidation. The photocatalytic NO conversion pathway on α-Bi2O3 and β-Bi2O3 can be tuned by the different surface defect structures. This work could provide a novel strategy to regulate the photocatalytic activity and conversion pathway via the synergistic effects of crystal structure and oxygen vacancy.
基金supported by the National Natural Science Foundation of China (21631004, 21371053,and 21573062)the Science Fund for Distinguished Young Scholar of Heilongjiang University (JCL201501)the Fundamental Research Funds for the Heilongjiang University of Heilongjiang Province of China(HDRCCX2016202)
文摘Gaining insight into the structure evolution of transition-metal phosphides during anodic oxidation is significant to understand their oxygen evolution reaction(OER) mechanism, and then design highefficiency transition metal-based catalysts. Herein, NiCo_2P_x nanowires(NWs) vertically grown on Ni foam were adopted as the target to explore the in-situ morphology and chemical component reconstitution during the anodic oxidation. The major factors causing the transformation from NiCo_2P_x into the hierarchical NiCo_2P_x@CoNi(OOH)_x NWs are two competing reactions: the dissolution of NiCo_2P_x NWs and the oxidative re-deposition of dissolved Co^(2+) and Ni^(2+) ions, which is based primarily on the anodic bias applied on NiCo2 Px NWs. The well balance of above competing reactions, and local pH on the surface of NiCo_2P_x NW modulated by the anodic oxidation can serve to control the anodic electrodeposition and rearrangement of metal ions on the surface of NiCo_2P_x NWs, and the immediate conversion into CoNi(OOH)_x. Consequently, the regular hexagonal CoNi(OOH)_x nanosheets grew around NiCo_2P_x NWs.Benefiting from the active catalytic sites on the surface and the sufficient conductivity, the resultant NiCo_2P_x@CoNi(OOH)_x arrays also display good OER activity, in terms of the fast kinetics process, the high energy conversion efficiency, especially the excellent durability. The strategy of in-situ structure reconstitution by electrochemical reaction described here offers a reliable and valid way to construct the highly active systems for various electrocatalytic applications.
基金Research in the authors'lab has been supported by The University of Texas MD Anderson Cancer Center,National Institutes of Health grants R01CA181196,R01CA190370,R01CA244144,and R01CA247992(to BG)a CPRIT Research Training Grant(RP170067)+1 种基金the Dr.John J.Kopchick Research Award from The Un iversity of Texas MD Anders on Cancer Center UTHealth Graduate School of Biomedical Sciences(to PK)This work was also supported in part by Cancer Center Support(Core)Grant P30 CA016672 from the National Cancer Institute,to The University of Texas MD Anderson Cancer Center.
文摘Oxygen,iron,and polyunsaturated fatty acids(PUFAs;fatty acids containing more than one double bond)are all beneficial to our cellular lives.Incorporation of these components into cellular processes,however,comes at a cost:the bis-allylic structure of PUFAs and the enrichment of cellular environments with iron and oxygen render PUFA-containing phospholipids(PUFA-PLs)particularly susceptible to peroxidation(Yang and Stockwell,2016).
基金supported by the National Natural Science Foundation of China(22072107,21872105)the Science&Technology Commission of Shanghai Municipality(19DZ2271500)the Fundamental Research Funds for the Central Universities.
文摘Air cathode performance is essential for rechargeable zinc–air batteries(ZABs).In this study,we develop a self-templated synthesis technique for fabricating bimetallic alloys(FeNi_(3)),bimetallic nitrides(FeNi_(3)N)and heterostructured FeNi_(3)/FeNi_(3)N hollow nanotubes.Owing to its structural and compositional advantages,FeNi_(3)/FeNi_(3)N exhibits remarkable bifunctional oxygen electrocatalytic performance with an extremely small potential gap of 0.68V between the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR).Theoretical calculations reveal reduced Gibbs free energy for the rate-limiting O–O bond formation during OER due to the self-adaptive surface reconfiguration,which induces a synergistic effect between Fe(Ni)OOH developed in situ on the surface and the inner FeNi_(3)/FeNi_(3)N.ZAB fabricated using the FeNi_(3)/FeNi_(3)N catalyst shows high power density,small charge/discharge voltage gap and excellent cycling stability.In addition to its excellent battery performance,the corresponding quasi-solid-state ZAB shows robust flexibility and integrability.The synthesis method is extended to prepare a CoFe/CoFeN oxygen electrocatalyst,demonstrating its applicability to other iron-group elements.
基金the financial supports from the National Natural Science Foundation of China(91545202,U1508203)the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB17000000)+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciencesthe Liaoning Revitalization Talents Program(XLYC1807066)~~
文摘Water-based rechargeable metal-air batteries play an important role in the storage and conversion of renewable electric energy.However,the sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have limited the practical application of rechargeable metal-air batteries.Most of reviews were focused on single functional electrocatalysts while few on bifunctional electrocatalysts.It is indispensable but challenging to design a bifunctional electrocatalyst that is active and stable to the two reactions.Recently,attempts to develop high active bifunctional electrocatalysts for both ORR and OER increase rapidly.Much work is focused on the micro-nano design of advanced structures to improve the performance of bifunctional electrocatalyst.Transition-metal materials,carbon materials and composite materials,and the methods developed to prepare micro-nano structures,such as electrochemical methods,chemical vapor deposition,hydrothermal methods and template methods are reported in literatures.Additionally,many strategies,such as adjustments of electronic structures,oxygen defects,metal-oxygen bonds,interfacial strain,nano composites,heteroatom doping etc.,have been used extensively to design bifunctional electrocatalysts.To well understand the achievements in the recent literatures,this review focuses on the micro-nano structural design of materials,and the related methods and strategies are classed into two groups for the improvement of intrinsic and apparent activities.The fine adjustment of nano structures and an in-depth understanding of the reaction mechanism are also discussed briefly.