In the present study,high-quality apatite-type La9.33Ge6O26 powders are successfully synthesized by a facile moltensalt synthesis method（MSSM） at low temperatures,using Li Cl,Li Cl/Na Cl mixture（mass ratio 1：1） a...In the present study,high-quality apatite-type La9.33Ge6O26 powders are successfully synthesized by a facile moltensalt synthesis method（MSSM） at low temperatures,using Li Cl,Li Cl/Na Cl mixture（mass ratio 1：1） as molten salt,respectively.Experimental results indicate that the optimal mass ratio between reactant and molten salt is 1：2,and Li Cl/Na Cl mixed molten-salt is more beneficial for forming high-quality La9.33Ge6O26 powders than Li Cl individual molten-salt.Comparing with the conventional solid-state reaction method（SSRM）,the synthesis temperature of apatitetype La9.33Ge6O26 powders using the MSSM decreases more than 350℃,which can effectively avoid Ge loss in the preparation process of precursor powders.Furthermore,the powders obtained by the MSSM are homogeneous,nonagglomerated and well crystallized,which are very favorable for gaining dense pellets in the premise of avoiding Ge loss.On the basis of high-quality precursor powders,the dense and pure ceramic pellets of La（9.33）Ge6O（26） are gained at a low temperature of 1100℃ for 2 h,which exhibit higher conductivities（σ850℃（Li Cl）= 2.3 × 10^-2 S·cm^-1,σ850 ℃（Li Cl/Na Cl） = 4.9 × 10^-2 S·cm^-1） and lower activation energies（Ea（Li Cl）= 1.02 e V,Ea（Li Cl/Na Cl）= 0.99 e V） than that synthesized by the SSRM.展开更多
The surface characteristics of ZnO were synthetically optimized by a self-designed simultaneous etching and W-doping hydrothermal method utilizing as-prepared ZnO nanorod(NR)array films as the template.Benefiting from...The surface characteristics of ZnO were synthetically optimized by a self-designed simultaneous etching and W-doping hydrothermal method utilizing as-prepared ZnO nanorod(NR)array films as the template.Benefiting from the etching and regrowth process and the different structural stabilities of the various faces of ZnO NRs,the uniquely etched and W-doped ZnO(EWZ)nanotube(NT)array films with larger surface area,more active sites and better energy band structure were used to improve the photoelectrochemical(PEC)performance and the loading quality of CdS quantum dots(QDs).On the basis of their better surface characteristics,the CdS QDs were uniformly loaded on EWZ NT array film with a good coverage ratio and interface connection;this effectively improved the light-harvesting ability,charge transportation and separation as well as charge injection efficiency during the PEC reaction.Therefore,all the CdS QD-sensitized EWZ NT array films exhibited significantly enhanced PEC performance.The CdS/EWZ-7 composite films exhibited the optimal photocurrent density with a value of 12 mA·cm^(-2),2.5 times higher than that of conventional CdS/ZnO-7 composite films under the same sensitization times with CdS QDs.The corresponding etching and optimizing mechanisms were also discussed.展开更多
The zinc oxide(ZnO)nanoparticles(NPs)sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide(H_(2)S)gas.The sphere-like ZnO NPs were charac...The zinc oxide(ZnO)nanoparticles(NPs)sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide(H_(2)S)gas.The sphere-like ZnO NPs were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),x-ray diffraction(XRD),energy dispersive x-ray analysis(EDX),and their H_(2)S sensing performance were measured at room temperature.Testing results indicate that the ZnO NPs exhibit excellent response to H_(2)S gas at room temperature.The response value of the optimal sample to750 ppb H_(2)S is 73.3%,the detection limit reaches to 30 ppb,and the response value is 7.5%.Furthermore,the effects of the calcining time and thickness of the film on the gas-sensing performance were investigated.Both calcining time and film thickness show a negative correlation with the H_(2)S sensing performance.The corresponding reaction mechanism of H_(2)S detection was also discussed.展开更多
Potassium-ion hybrid capacitors(PIHCs)reconcile the advantages of batteries and supercapacitors,exhibiting both good energy density and high-power density.However,the low-rate performance and poor cycle stability of b...Potassium-ion hybrid capacitors(PIHCs)reconcile the advantages of batteries and supercapacitors,exhibiting both good energy density and high-power density.However,the low-rate performance and poor cycle stability of battery-type anodes hinder their practical application.Herein,phosphorus/nitrogen co-doped hollow carbon fibers(P-HCNFs)are prepared by a facile template method.The stable grape-like structure with continuous and interconnected cavity structure is an ideal scaffold for shortening the ion transport and relieving volume expansion,while the introduction of P atoms and intrinsic N atoms can create abundant extrinsic/intrinsic defects and additional active sites,reducing the K+diffusion barrier and improving the capacitive-controlled capacity.The P-HCNFs delivers a high specific capacity of 310 mAh·g^(-1)at 0.1 A·g^(-1)with remarkable ultra-high-rate performance(140 mAh·g^(-1)at 50 A·g^(-1))and retains an impressive capacity retention of 87%after 10,000 cycles at 10 A·g^(-1).As expected,the as-assembled PIHCs present a high energy density(115.8 Wh·kg^(-1)at 378.0 W·kg^(-1))and excellent capacity retention of 91%after 20,000 cycles.This work not only shows great potential for utilizing heteroatom-doping and structural design strategies to boost potassium storage,but also paves the way for advancing the practicality of high-energy PIHCs devices.展开更多
With the advantages of metal conductivity,large specific surface area,and rich surface functional groups,two-dimensional(2D)MXenes have shown great potential in the field of gas sensing.However,gas sensors fabricated ...With the advantages of metal conductivity,large specific surface area,and rich surface functional groups,two-dimensional(2D)MXenes have shown great potential in the field of gas sensing.However,gas sensors fabricated with pristine MXenes generally suffer from several problems such as low sensitivity,poor selectivity,significant baseresistance drift,and poor environment stability.Therefore,many efforts have been devoted to overcoming these problems.In this review,we review the progress on MXenebased gas sensors and summarize several efficient strategies(including structural design,surface modification,inorganic Schottky j unction/heterojunction sensitization,polymer addition,and metal-ion intercalation)to promote the gassensing performance.In addition,the major challenges and future development directions of MXene-based gas sensors are also outlined in the present review.展开更多
基金Project supported by the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2016FB16,ZR2015AQ010,and ZR2016AQ08)the Shandong University of Technology at Zibo and Zibo City Integration Development Project,China(Grant No.2016ZBXC205)
文摘In the present study,high-quality apatite-type La9.33Ge6O26 powders are successfully synthesized by a facile moltensalt synthesis method（MSSM） at low temperatures,using Li Cl,Li Cl/Na Cl mixture（mass ratio 1：1） as molten salt,respectively.Experimental results indicate that the optimal mass ratio between reactant and molten salt is 1：2,and Li Cl/Na Cl mixed molten-salt is more beneficial for forming high-quality La9.33Ge6O26 powders than Li Cl individual molten-salt.Comparing with the conventional solid-state reaction method（SSRM）,the synthesis temperature of apatitetype La9.33Ge6O26 powders using the MSSM decreases more than 350℃,which can effectively avoid Ge loss in the preparation process of precursor powders.Furthermore,the powders obtained by the MSSM are homogeneous,nonagglomerated and well crystallized,which are very favorable for gaining dense pellets in the premise of avoiding Ge loss.On the basis of high-quality precursor powders,the dense and pure ceramic pellets of La（9.33）Ge6O（26） are gained at a low temperature of 1100℃ for 2 h,which exhibit higher conductivities（σ850℃（Li Cl）= 2.3 × 10^-2 S·cm^-1,σ850 ℃（Li Cl/Na Cl） = 4.9 × 10^-2 S·cm^-1） and lower activation energies（Ea（Li Cl）= 1.02 e V,Ea（Li Cl/Na Cl）= 0.99 e V） than that synthesized by the SSRM.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61904098 and 11904209)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2019QF018)Higher Education Research and Development Program of Shandong Province,China(Grant No.J18KA242).
文摘The surface characteristics of ZnO were synthetically optimized by a self-designed simultaneous etching and W-doping hydrothermal method utilizing as-prepared ZnO nanorod(NR)array films as the template.Benefiting from the etching and regrowth process and the different structural stabilities of the various faces of ZnO NRs,the uniquely etched and W-doped ZnO(EWZ)nanotube(NT)array films with larger surface area,more active sites and better energy band structure were used to improve the photoelectrochemical(PEC)performance and the loading quality of CdS quantum dots(QDs).On the basis of their better surface characteristics,the CdS QDs were uniformly loaded on EWZ NT array film with a good coverage ratio and interface connection;this effectively improved the light-harvesting ability,charge transportation and separation as well as charge injection efficiency during the PEC reaction.Therefore,all the CdS QD-sensitized EWZ NT array films exhibited significantly enhanced PEC performance.The CdS/EWZ-7 composite films exhibited the optimal photocurrent density with a value of 12 mA·cm^(-2),2.5 times higher than that of conventional CdS/ZnO-7 composite films under the same sensitization times with CdS QDs.The corresponding etching and optimizing mechanisms were also discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11904209 and 61904098)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2019QF018)Higher Education Research and Development Program of Shandong Province,China(Grant No.J18KA242)。
文摘The zinc oxide(ZnO)nanoparticles(NPs)sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide(H_(2)S)gas.The sphere-like ZnO NPs were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),x-ray diffraction(XRD),energy dispersive x-ray analysis(EDX),and their H_(2)S sensing performance were measured at room temperature.Testing results indicate that the ZnO NPs exhibit excellent response to H_(2)S gas at room temperature.The response value of the optimal sample to750 ppb H_(2)S is 73.3%,the detection limit reaches to 30 ppb,and the response value is 7.5%.Furthermore,the effects of the calcining time and thickness of the film on the gas-sensing performance were investigated.Both calcining time and film thickness show a negative correlation with the H_(2)S sensing performance.The corresponding reaction mechanism of H_(2)S detection was also discussed.
基金financially supported by the Youth Innovation Team of Colleges and Universities in Shandong Province(No.2022KJ223)the National Natural Science Foundation of China(Nos.22078179 and 52007110)+1 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2022JQ10 and ZR2021MA026)Taishan S cholar Foundation(No.tsqn201812063)。
文摘Potassium-ion hybrid capacitors(PIHCs)reconcile the advantages of batteries and supercapacitors,exhibiting both good energy density and high-power density.However,the low-rate performance and poor cycle stability of battery-type anodes hinder their practical application.Herein,phosphorus/nitrogen co-doped hollow carbon fibers(P-HCNFs)are prepared by a facile template method.The stable grape-like structure with continuous and interconnected cavity structure is an ideal scaffold for shortening the ion transport and relieving volume expansion,while the introduction of P atoms and intrinsic N atoms can create abundant extrinsic/intrinsic defects and additional active sites,reducing the K+diffusion barrier and improving the capacitive-controlled capacity.The P-HCNFs delivers a high specific capacity of 310 mAh·g^(-1)at 0.1 A·g^(-1)with remarkable ultra-high-rate performance(140 mAh·g^(-1)at 50 A·g^(-1))and retains an impressive capacity retention of 87%after 10,000 cycles at 10 A·g^(-1).As expected,the as-assembled PIHCs present a high energy density(115.8 Wh·kg^(-1)at 378.0 W·kg^(-1))and excellent capacity retention of 91%after 20,000 cycles.This work not only shows great potential for utilizing heteroatom-doping and structural design strategies to boost potassium storage,but also paves the way for advancing the practicality of high-energy PIHCs devices.
基金financially supported by the National Natural Science Foundation of China(Nos.11904209 and 61904098)the Natural Science Foundation of Shandong Province(No.ZR2019QF018)the Higher Education Research and Development Program of Shandong Province(No.J18KA242)
文摘With the advantages of metal conductivity,large specific surface area,and rich surface functional groups,two-dimensional(2D)MXenes have shown great potential in the field of gas sensing.However,gas sensors fabricated with pristine MXenes generally suffer from several problems such as low sensitivity,poor selectivity,significant baseresistance drift,and poor environment stability.Therefore,many efforts have been devoted to overcoming these problems.In this review,we review the progress on MXenebased gas sensors and summarize several efficient strategies(including structural design,surface modification,inorganic Schottky j unction/heterojunction sensitization,polymer addition,and metal-ion intercalation)to promote the gassensing performance.In addition,the major challenges and future development directions of MXene-based gas sensors are also outlined in the present review.
