As the bridge between basic principles and applications of nanotechnology,nanofabrication methods play significant role in supporting the development of nanoscale science and engineering,which is changing and improvin...As the bridge between basic principles and applications of nanotechnology,nanofabrication methods play significant role in supporting the development of nanoscale science and engineering,which is changing and improving the production and lifestyle of the human.Photo lithography and other alternative technologies,such as nanoimprinting,electron beam lithography,focused ion beam cutting,and scanning probe lithography,have brought great progress of semiconductor industry,IC manufacturing and micro/nanoelectromechanical system(MEMS/NEMS)devices.However,there remains a lot of challenges,relating to the resolution,cost,speed,and so on,in realizing high-quality products with further development of nanotechnology.None of the existing techniques can satisfy all the needs in nanoscience and nanotechnology at the same time,and it is essential to explore new nanofabrication methods.As a newly developed scanning probe microscope(SPM)-based lithography,friction-induced nanofabrication provides opportunities for maskless,flexible,low-damage,low-cost and environment-friendly processing on a wide variety of materials,including silicon,quartz,glass surfaces,and so on.It has been proved that this fabrication route provides with a broad application prospect in the fabrication of nanoimprint templates,microfluidic devices,and micro/nano optical structures.This paper hereby involved the principals and operations of friction-induced nanofabrication,including friction-induced selective etching,and the applications were reviewed as well for looking ahead at opportunities and challenges with nanotechnology development.The present review will not only enrich the knowledge in nanotribology,but also plays a positive role in promoting SPM-based nanofabrication.展开更多
Silver nanocubes enriched with {100} facets have been extensively used for surface-enhanced Raman scattering. Herein, we report a new water-phase synthesis method for weU-defined Ag nanocubes with tunable sizes via a ...Silver nanocubes enriched with {100} facets have been extensively used for surface-enhanced Raman scattering. Herein, we report a new water-phase synthesis method for weU-defined Ag nanocubes with tunable sizes via a two-step procedure at room temperature. First, irregularly shaped Ag nanoparticles （INPs） were prepared by reducing silver ammonia solution using ethylal. Second, the agglomerated INPs were selectively etched with HNO3 and C1- to yield {100} facet-rich mesoporous Ag nanocubes. The mechanism of Ag-nanocube formation and growth was investigated in detail by elucidating the involved chemical reactions and physical changes at each step during the synthesis. The addition of C1- anions was responsible for facilitating Ag nanoparticle growth by removing surface-adsorbed Ag＋ species, thereby eliminating inter-particle repulsive forces. This agglomeration was found crucial for the subsequent selective oxidation of Ag nanoparticles because the protective agent used, polyvinylpyrrolidone （PVP）, was the most effective one for adsorption on the surfaces of Ag nanoparticles of size greater than approximately 50 nm. Importantly mesopores were found inside the Ag nanocubes; this can be attributed to the unavoidable imperfect packing during the agglomeration of INPs. The newly prepared Ag nanocubes were further used to enhance the Raman signal of rhodamine 6G, which is capable of reducing the detection limitation to 10-16 mol·L-1.展开更多
Surface reconstruction yields real active species in electrochemical oxygen evolution reaction(OER)conditions;however,rationally regulating reconstruction in a targeted manner for constructing highly active OER electr...Surface reconstruction yields real active species in electrochemical oxygen evolution reaction(OER)conditions;however,rationally regulating reconstruction in a targeted manner for constructing highly active OER electrocatalysts remains a formidable challenge.Here,an electrochemical activation strategy with selective etching was utilized to guide the reconstruction process of a hybrid cobalt-molybdenum oxide(CoMoO_(4)/Co_(3)O_(4)@CC)in a favorable direction to improve the OER performance.Both in-situ Raman and multiple ex-situ characterization tools demonstrate that controlled surface reconstruction can be easily achieved through Mo etching,with the formation of a dynamically stable amorphous-crystalline heterostructure.Theoretical calculations together with experimental results reveal that the synergistic effects between amorphous CoOOH and crystalline Co_(3)O_(4) are crucial in enhancing the catalytic performance.Consequently,the reconstructed CoMoO_(4)/Co_(3)O_(4)@CC exhibits a low overpotential of 250 mV to achieve a current density of 10 mA cm^(-2) in 1 M KOH,and more importantly it can be practiced in electrolytic water splitting and rechargeable zinc-air batteries devices,achieving ultra-long stability for over 500 and 1200 h,respectively.This work provides a promising route for the construction of high-performance electrocatalysts.展开更多
The water-gas shift(WGS) reaction is an essential industrial reaction for upgrading hydrogen(H2) by removing carbon monoxide(CO), while highly efficient platinum(Pt)-based catalysts for WGS with simultaneously high ac...The water-gas shift(WGS) reaction is an essential industrial reaction for upgrading hydrogen(H2) by removing carbon monoxide(CO), while highly efficient platinum(Pt)-based catalysts for WGS with simultaneously high activity and stability are still yet to be developed due to the poisoning issue during the reaction. Herein, we report on the porous PtPb peanut nanocrystals(porous PtPb PNCs) and porous PtPb octahedron nanocrystals(porous PtPb ONCs) with controllable ratios of Pt/Pb as extremely active and stable catalysts towards WGS reaction. It exhibits the composition-dependent activity with porous PtPb PNCs-40/ZnO being the most active for WGS to H_2, 16.9 times higher than that of the commercial Pt/C. The porous PtPb PNCs-40/ZnO also display outstanding durability with barely activity decay and negligible structure and composition changes after ten successive reaction cycles. X-ray photoelectron spectroscopy(XPS) results reveal that the suitable binding energy of Pt 4f_(7/2) and the high ratio of Pt(0)to Pt(II) in porous PtPb PNCs/ZnO and porous PtPb ONCs/ZnO are crucial for the enhanced WGS activity.The CO stripping results indicate the optimized CO adsorption strength on the Pt surface ensure the excellent WGS activity and the outstanding durability. The present work demonstrates an important advance in tuning the porous metal nanomaterials as highly efficient and durable catalysts for catalysis,energy conversion and beyond.展开更多
We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the c...We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51775462,51991373).
文摘As the bridge between basic principles and applications of nanotechnology,nanofabrication methods play significant role in supporting the development of nanoscale science and engineering,which is changing and improving the production and lifestyle of the human.Photo lithography and other alternative technologies,such as nanoimprinting,electron beam lithography,focused ion beam cutting,and scanning probe lithography,have brought great progress of semiconductor industry,IC manufacturing and micro/nanoelectromechanical system(MEMS/NEMS)devices.However,there remains a lot of challenges,relating to the resolution,cost,speed,and so on,in realizing high-quality products with further development of nanotechnology.None of the existing techniques can satisfy all the needs in nanoscience and nanotechnology at the same time,and it is essential to explore new nanofabrication methods.As a newly developed scanning probe microscope(SPM)-based lithography,friction-induced nanofabrication provides opportunities for maskless,flexible,low-damage,low-cost and environment-friendly processing on a wide variety of materials,including silicon,quartz,glass surfaces,and so on.It has been proved that this fabrication route provides with a broad application prospect in the fabrication of nanoimprint templates,microfluidic devices,and micro/nano optical structures.This paper hereby involved the principals and operations of friction-induced nanofabrication,including friction-induced selective etching,and the applications were reviewed as well for looking ahead at opportunities and challenges with nanotechnology development.The present review will not only enrich the knowledge in nanotribology,but also plays a positive role in promoting SPM-based nanofabrication.
文摘Silver nanocubes enriched with {100} facets have been extensively used for surface-enhanced Raman scattering. Herein, we report a new water-phase synthesis method for weU-defined Ag nanocubes with tunable sizes via a two-step procedure at room temperature. First, irregularly shaped Ag nanoparticles （INPs） were prepared by reducing silver ammonia solution using ethylal. Second, the agglomerated INPs were selectively etched with HNO3 and C1- to yield {100} facet-rich mesoporous Ag nanocubes. The mechanism of Ag-nanocube formation and growth was investigated in detail by elucidating the involved chemical reactions and physical changes at each step during the synthesis. The addition of C1- anions was responsible for facilitating Ag nanoparticle growth by removing surface-adsorbed Ag＋ species, thereby eliminating inter-particle repulsive forces. This agglomeration was found crucial for the subsequent selective oxidation of Ag nanoparticles because the protective agent used, polyvinylpyrrolidone （PVP）, was the most effective one for adsorption on the surfaces of Ag nanoparticles of size greater than approximately 50 nm. Importantly mesopores were found inside the Ag nanocubes; this can be attributed to the unavoidable imperfect packing during the agglomeration of INPs. The newly prepared Ag nanocubes were further used to enhance the Raman signal of rhodamine 6G, which is capable of reducing the detection limitation to 10-16 mol·L-1.
基金supported by the financial support of the Guangxi Science and Technology Major Projects(Guike AA23023033)。
文摘Surface reconstruction yields real active species in electrochemical oxygen evolution reaction(OER)conditions;however,rationally regulating reconstruction in a targeted manner for constructing highly active OER electrocatalysts remains a formidable challenge.Here,an electrochemical activation strategy with selective etching was utilized to guide the reconstruction process of a hybrid cobalt-molybdenum oxide(CoMoO_(4)/Co_(3)O_(4)@CC)in a favorable direction to improve the OER performance.Both in-situ Raman and multiple ex-situ characterization tools demonstrate that controlled surface reconstruction can be easily achieved through Mo etching,with the formation of a dynamically stable amorphous-crystalline heterostructure.Theoretical calculations together with experimental results reveal that the synergistic effects between amorphous CoOOH and crystalline Co_(3)O_(4) are crucial in enhancing the catalytic performance.Consequently,the reconstructed CoMoO_(4)/Co_(3)O_(4)@CC exhibits a low overpotential of 250 mV to achieve a current density of 10 mA cm^(-2) in 1 M KOH,and more importantly it can be practiced in electrolytic water splitting and rechargeable zinc-air batteries devices,achieving ultra-long stability for over 500 and 1200 h,respectively.This work provides a promising route for the construction of high-performance electrocatalysts.
基金supported by the Ministry of Science and Technology of China (2016YFA0204100, 2017YFA0208200)the National Natural Science Foundation of China (21571135)+2 种基金Young Thousand Talented Programthe Natural Science Foundation of Jiangsu Higher Education Institutions (17KJB150032)the Start-up Supports from Soochow Universitythe Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘The water-gas shift(WGS) reaction is an essential industrial reaction for upgrading hydrogen(H2) by removing carbon monoxide(CO), while highly efficient platinum(Pt)-based catalysts for WGS with simultaneously high activity and stability are still yet to be developed due to the poisoning issue during the reaction. Herein, we report on the porous PtPb peanut nanocrystals(porous PtPb PNCs) and porous PtPb octahedron nanocrystals(porous PtPb ONCs) with controllable ratios of Pt/Pb as extremely active and stable catalysts towards WGS reaction. It exhibits the composition-dependent activity with porous PtPb PNCs-40/ZnO being the most active for WGS to H_2, 16.9 times higher than that of the commercial Pt/C. The porous PtPb PNCs-40/ZnO also display outstanding durability with barely activity decay and negligible structure and composition changes after ten successive reaction cycles. X-ray photoelectron spectroscopy(XPS) results reveal that the suitable binding energy of Pt 4f_(7/2) and the high ratio of Pt(0)to Pt(II) in porous PtPb PNCs/ZnO and porous PtPb ONCs/ZnO are crucial for the enhanced WGS activity.The CO stripping results indicate the optimized CO adsorption strength on the Pt surface ensure the excellent WGS activity and the outstanding durability. The present work demonstrates an important advance in tuning the porous metal nanomaterials as highly efficient and durable catalysts for catalysis,energy conversion and beyond.
基金Supported by the National Basic Research Program of China under Grant No 2012CB921804the National Natural Science Foundation of China under Grant Nos 11204236 and 61308006the Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated.
