The electrochemical reduction of CO2 is a promising solution for sustainable energy research and carbon emissions.However,this solution has been challenged by the lack of active and selective catalysts.Here,we report ...The electrochemical reduction of CO2 is a promising solution for sustainable energy research and carbon emissions.However,this solution has been challenged by the lack of active and selective catalysts.Here,we report a two-step synthesis of 3D ordered mesoporous Cu sphere arrays,which is fabricated by a dual template method using a poly methyl methacrylate(PMMA) inverse opal and the nonionic surfactant Brij 58 to template the mesostructure within the regular voids of a colloidal crystal.Therefo re,the well-ordered 3D interconnected bi-continuous mesopore s structure has advantages of abundant exposed catalytically active sites,efficient mass transport,and high electrical conductivity,which result in excellent electrocatalytic CO2 RR perfo rmance.The prepared 3D ordered mesoporous Cu sphere array(3 D-OMCuSA) exhibits a low onset potential of-0.4 V at a 1 mA cm^-2 electrode current density,a low Tafel slope of 109.6 mV per decade and a long-term durability in 0.1 M potassium bicarbonate.These distinct features of 3 D-OMCuSA render it a promising method for the further develo p ment of advanced electrocatalytic materials for CO2 reduction.展开更多
In situ scanning tunneling microscopy (STM) and cyclic voltammetry were employed to investigate the adsorption structures of three semi-crown ligands on an Au(111) surface under the potential control. It is found that...In situ scanning tunneling microscopy (STM) and cyclic voltammetry were employed to investigate the adsorption structures of three semi-crown ligands on an Au(111) surface under the potential control. It is found that all the molecules formed ordered arrays in 0.1 mol/L HClO4 solution, although their geometric structures are complex and asymmetric. The driving force was supposed to come from the balance between intermolecular and molecule-substrate interactions. High resolution STM images revealed internal molecular structures, orientations and packing arrangements in the ordered adlayers. The results are useful for preparing ordered arrays of transition metal-mediated nanostructures.展开更多
When a perpendicular magnetic field penetrates a thin slab of a type-Ⅱ superconductor it produces vortices,with one vortex per flux quantum,h/2e.The vortices interact repulsively and form an ordered array(Abrikosov l...When a perpendicular magnetic field penetrates a thin slab of a type-Ⅱ superconductor it produces vortices,with one vortex per flux quantum,h/2e.The vortices interact repulsively and form an ordered array(Abrikosov lattice)in clean systems,while strong disorder changes the lattice into a vortex glass.The collective vortex dynamics is extremely vulnerable to external perturbations.Consequently,although of great importance,experimental observation is limited.Here we investigate type-Ⅱ superconducting films(PdBi_(2)and NbSe_(2))with surface acoustic waves(SAWs)at mK temperature.When sweeping the magnetic field at an extremely slow rate,we observe a series of spikes in the attenuation and velocity of the SAW,on average separated in field by approximately Hc1.We propose the following scenario:The vortex-free region at the edges of the film produces an edge barrier across which the vortices can enter or leave.When the applied field changes,the induced supercurrents flowing along this edge region lowers this barrier until there is an instability.At that point,vortices avalanche into(or out of)the bulk and change the vortex crystal,suggested by the sharp jump in each such spike.The vortices then gradually relax to a new stable pinned configuration,leading to a~30 s relaxation after the jump.Our observation enriches the limited experimental evidence on the important topic of real-time vortex dynamics in superconductors.展开更多
基金This work was supported by the NSFC grant number21607113the Natural Science Foundation of Tianjin grant number 17JCQNJC07700。
文摘The electrochemical reduction of CO2 is a promising solution for sustainable energy research and carbon emissions.However,this solution has been challenged by the lack of active and selective catalysts.Here,we report a two-step synthesis of 3D ordered mesoporous Cu sphere arrays,which is fabricated by a dual template method using a poly methyl methacrylate(PMMA) inverse opal and the nonionic surfactant Brij 58 to template the mesostructure within the regular voids of a colloidal crystal.Therefo re,the well-ordered 3D interconnected bi-continuous mesopore s structure has advantages of abundant exposed catalytically active sites,efficient mass transport,and high electrical conductivity,which result in excellent electrocatalytic CO2 RR perfo rmance.The prepared 3D ordered mesoporous Cu sphere array(3 D-OMCuSA) exhibits a low onset potential of-0.4 V at a 1 mA cm^-2 electrode current density,a low Tafel slope of 109.6 mV per decade and a long-term durability in 0.1 M potassium bicarbonate.These distinct features of 3 D-OMCuSA render it a promising method for the further develo p ment of advanced electrocatalytic materials for CO2 reduction.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.20025308&20177025)National Key Project on Basic Research(Grant No.G2000077501)and the Chinese Academy of Sciences.
文摘In situ scanning tunneling microscopy (STM) and cyclic voltammetry were employed to investigate the adsorption structures of three semi-crown ligands on an Au(111) surface under the potential control. It is found that all the molecules formed ordered arrays in 0.1 mol/L HClO4 solution, although their geometric structures are complex and asymmetric. The driving force was supposed to come from the balance between intermolecular and molecule-substrate interactions. High resolution STM images revealed internal molecular structures, orientations and packing arrangements in the ordered adlayers. The results are useful for preparing ordered arrays of transition metal-mediated nanostructures.
基金supported by the National Key Research Program of China(Grant Nos.2021YFA1401900,2022YFA1403300,and 2020YFA0309100)the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0302602 and 2024ZD0300103)+1 种基金the National Natural Science Foundation of China(Grant No.12074073)for samplefabrication and measurementthe support by the The Basic Research Program of the Chinese Academy of Sciences Based on Major Scientific Infrastructures(Grant No.JZHKYPT-2021-08).
文摘When a perpendicular magnetic field penetrates a thin slab of a type-Ⅱ superconductor it produces vortices,with one vortex per flux quantum,h/2e.The vortices interact repulsively and form an ordered array(Abrikosov lattice)in clean systems,while strong disorder changes the lattice into a vortex glass.The collective vortex dynamics is extremely vulnerable to external perturbations.Consequently,although of great importance,experimental observation is limited.Here we investigate type-Ⅱ superconducting films(PdBi_(2)and NbSe_(2))with surface acoustic waves(SAWs)at mK temperature.When sweeping the magnetic field at an extremely slow rate,we observe a series of spikes in the attenuation and velocity of the SAW,on average separated in field by approximately Hc1.We propose the following scenario:The vortex-free region at the edges of the film produces an edge barrier across which the vortices can enter or leave.When the applied field changes,the induced supercurrents flowing along this edge region lowers this barrier until there is an instability.At that point,vortices avalanche into(or out of)the bulk and change the vortex crystal,suggested by the sharp jump in each such spike.The vortices then gradually relax to a new stable pinned configuration,leading to a~30 s relaxation after the jump.Our observation enriches the limited experimental evidence on the important topic of real-time vortex dynamics in superconductors.
