Single-atom site(SA)catalysts on N-doped carbon(CN)materials exhibit prominent performance for their active sites being M-Nx.Due to the commonly random doping behaviors of N species in these CN,it is a tough issue to ...Single-atom site(SA)catalysts on N-doped carbon(CN)materials exhibit prominent performance for their active sites being M-Nx.Due to the commonly random doping behaviors of N species in these CN,it is a tough issue to finely regulate their doping types and clarify their effect on the catalytic property of such catalysts.Herein,we report that the N-doping type in CN can be dominated as pyrrolic-N and pyridinic-N respectively through compounding with different metal oxides.It is found that the proportion of distinct doped N species in CN depends on the acidity and basicity of compounded metal oxide host.Owing to the coordination by pyrrolic-N,the SA Cu catalyst displays an enhanced activity(two-fold)for transfer hydrogenation of quinoline to access the valuable molecule tetrahydroquinoline with a good selectivity(99%)under mild conditions.The higher electron density of SA Cu species induced by the predominate pyrrolic-N coordination benefits the hydrogen transfer process and reduces the energy barrier of the hydrogenation pathway,which accounts for the improved catalytic effeciency.展开更多
针对无线电能传输(wireless power transfer,WPT)系统处于不同负载、耦合系数和频率的运行状况进行分析,基于T型等效电路和二端口网络,得到了SS、LCL和LCC3种谐振网络的传递函数模型。将3种谐振网络的传输特性进行分析,实验结果表明3种...针对无线电能传输(wireless power transfer,WPT)系统处于不同负载、耦合系数和频率的运行状况进行分析,基于T型等效电路和二端口网络,得到了SS、LCL和LCC3种谐振网络的传递函数模型。将3种谐振网络的传输特性进行分析,实验结果表明3种谐振网络均为恒流输出,其中LCC网络具有随负载和耦合系数变化呈单调增的关系,有效地解决SS和LCL网络中存在传输功率过小等问题,并抑制系统处于偏谐振或低耦合状态下出现功率过载的情况。最后搭建了一台基于移相全桥(phase shift full bridge, PSFB)控制的LCC型WPT实验样机,能适应宽负载变化范围,当逆变器处于不同的移相角下均能保持零相角(zero phase angle, ZPA)的条件,使得系统具有较高的传输效率。展开更多
The van der Waals heterostructures have evolved as novel materials for complementing the Si-based semiconductor technologies.Group-10 noble metal dichalcogenides(e.g.,PtS_(2),PtSe_(2),PdS_(2),and PdSe_(2))have been li...The van der Waals heterostructures have evolved as novel materials for complementing the Si-based semiconductor technologies.Group-10 noble metal dichalcogenides(e.g.,PtS_(2),PtSe_(2),PdS_(2),and PdSe_(2))have been listed into two-dimensional(2D)materials toolkit to assemble van der Waals heterostructures.Among them,PdSe_(2) demonstrates advantages of high stability in air,high mobility,and wide tunable bandgap.However,the regulation of p-type doping of PdSe_(2) remains unsolved problem prior to fabricating p–n junction as a fundamental platform of semiconductor physics.Besides,a quantitative method for the controllable doping of PdSe_(2) is yet to be reported.In this study,the doping level of PdSe_(2) was correlated with the concentration of Lewis acids,for example,SnCl_(4),used for soaking.Considering the transfer characteristics,the threshold voltage(the gate voltage corresponding to the minimum drain current)increased after SnCl_(4) soaking treatment.PdSe_(2) transistors were soaked in SnCl_(4) solutions with five different concentrations.The threshold voltages from the as-obtained transfer curves were extracted for linear fitting to the threshold voltage versus doping concentration correlation equation.This study provides in-depth insights into the controllable p-type doping of PdSe_(2).It may also push forward the research of the regulation of conductivity behaviors of 2D materials.展开更多
基金supported by the National Key R&D Program of China(Nos.2018YFA0702003 and 2016YFA0202801)the National Natural Science Foundation of China(Nos.21890383,21671117,21871159,and 21901135)+2 种基金the National Postdoctoral Program for Innovative Talents,the Shuimu Tsinghua Scholar,Science and Technology Key Project of Guangdong Province of China(No.2020B010188002)Beijing Municipal Science&Technology Commission(No.Z191100007219003)We thank the BL14W1 station in Shanghai Synchrotron Radiation Facility(SSRF)and 1W1B station for XAFS measurement in Beijing Synchrotron Radiation Facility(BSRF).
文摘Single-atom site(SA)catalysts on N-doped carbon(CN)materials exhibit prominent performance for their active sites being M-Nx.Due to the commonly random doping behaviors of N species in these CN,it is a tough issue to finely regulate their doping types and clarify their effect on the catalytic property of such catalysts.Herein,we report that the N-doping type in CN can be dominated as pyrrolic-N and pyridinic-N respectively through compounding with different metal oxides.It is found that the proportion of distinct doped N species in CN depends on the acidity and basicity of compounded metal oxide host.Owing to the coordination by pyrrolic-N,the SA Cu catalyst displays an enhanced activity(two-fold)for transfer hydrogenation of quinoline to access the valuable molecule tetrahydroquinoline with a good selectivity(99%)under mild conditions.The higher electron density of SA Cu species induced by the predominate pyrrolic-N coordination benefits the hydrogen transfer process and reduces the energy barrier of the hydrogenation pathway,which accounts for the improved catalytic effeciency.
文摘针对无线电能传输(wireless power transfer,WPT)系统处于不同负载、耦合系数和频率的运行状况进行分析,基于T型等效电路和二端口网络,得到了SS、LCL和LCC3种谐振网络的传递函数模型。将3种谐振网络的传输特性进行分析,实验结果表明3种谐振网络均为恒流输出,其中LCC网络具有随负载和耦合系数变化呈单调增的关系,有效地解决SS和LCL网络中存在传输功率过小等问题,并抑制系统处于偏谐振或低耦合状态下出现功率过载的情况。最后搭建了一台基于移相全桥(phase shift full bridge, PSFB)控制的LCC型WPT实验样机,能适应宽负载变化范围,当逆变器处于不同的移相角下均能保持零相角(zero phase angle, ZPA)的条件,使得系统具有较高的传输效率。
基金the Natural Science Foundation of Shandong Province for Excellent Young Scholars(No.ZR2022YQ41)the fund(No.SKT2203)from the State Key Laboratories of Transducer Technology,Shanghai Institute of Microsystem and Information Technology+9 种基金Chinese Academy of Sciences for support.This work was partially supported by the National Key Research and Development Program of China(No.2022YFE0124200)the National Natural Science Foundation of China(No.U2241221)W.J.Z.thanks the Major innovation project of Shandong Province(No.2021CXGC010603)the National Natural Science Foundation of China(No.52022037)the Taishan Scholars Project Special Funds(No.TSQN201812083)The project was supported by the Foundation(No.GZKF202107)of State Key Laboratory of Biobased Material and Green PapermakingQilu University of Technology,Shandong Academy of Sciences.M.H.R.thanks the National Natural Science Foundation of China(No.52071225)the National Science Center and the Czech Republic under the ERDF program“Institute of Environmental Technology-Excellent Research”(No.CZ.02.1.01/0.0/0.0/16_019/0000853)the Sino-German Research Institute(No.GZ 1400)for supportS.X.H.thanks the National Natural Science Foundation of China(Nos.21976014 and 22276013)for funding,and thanks the Tianhe2-JK HPC for generous computer time.
文摘The van der Waals heterostructures have evolved as novel materials for complementing the Si-based semiconductor technologies.Group-10 noble metal dichalcogenides(e.g.,PtS_(2),PtSe_(2),PdS_(2),and PdSe_(2))have been listed into two-dimensional(2D)materials toolkit to assemble van der Waals heterostructures.Among them,PdSe_(2) demonstrates advantages of high stability in air,high mobility,and wide tunable bandgap.However,the regulation of p-type doping of PdSe_(2) remains unsolved problem prior to fabricating p–n junction as a fundamental platform of semiconductor physics.Besides,a quantitative method for the controllable doping of PdSe_(2) is yet to be reported.In this study,the doping level of PdSe_(2) was correlated with the concentration of Lewis acids,for example,SnCl_(4),used for soaking.Considering the transfer characteristics,the threshold voltage(the gate voltage corresponding to the minimum drain current)increased after SnCl_(4) soaking treatment.PdSe_(2) transistors were soaked in SnCl_(4) solutions with five different concentrations.The threshold voltages from the as-obtained transfer curves were extracted for linear fitting to the threshold voltage versus doping concentration correlation equation.This study provides in-depth insights into the controllable p-type doping of PdSe_(2).It may also push forward the research of the regulation of conductivity behaviors of 2D materials.
