The effects of Ce doping on the structure,optical,oxidation,thermal and magnetic properties of ZnS:Ce nanorods synthesized by a chemical co-precipitation method were reported.The crystalline phase transformation from ...The effects of Ce doping on the structure,optical,oxidation,thermal and magnetic properties of ZnS:Ce nanorods synthesized by a chemical co-precipitation method were reported.The crystalline phase transformation from cubic to hexagonal structure was observed upon doping ZnS with Ce.Magnetic measurements showed the existence of room temperature ferromagnetism in Ce-doped ZnS nanorods.X-ray photoelectron spectroscopic(XPS)measurements provided evidence for Zn-S bonds and oxidation state of Ce in the near-surface region.Raman spectrum provided evidence for the presence of defects as well as hexagonal structure of 5 wt.%Ce doped ZnS nanorods.Ce substitution induced shape evolution was studied by using TEM.DRS spectra further validated the incorporation of Ce^3+ions.The present study reveals that Ce doped ZnS nanorods may find applications in spintronic devices.展开更多
MoS_(2)is a promising electrocatalyst because of its natural abundance and outstanding electrochemical stability.However,the poor conductivity and low activity limit its catalytic performance;furthermore,MoS_(2)is una...MoS_(2)is a promising electrocatalyst because of its natural abundance and outstanding electrochemical stability.However,the poor conductivity and low activity limit its catalytic performance;furthermore,MoS_(2)is unable to satisfy the requirements of most industrial applications.In this study,to obtain a P-doped MoS_(2)catalyst with S vacancy defects,P is inserted into the MoS_(2)matrix via a solid phase ion exchange at room temperature.The optimal P-doping amount is 11.4 wt%,and the resultant catalyst delivers excellent electrocatalytic properties for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)with the corresponding overpotentials of 93 and 316 mV at 10 mA cm^(-2) in an alkaline solution;these values surpass the overpotentials of most previously reported MoS_(2)-based materials.Theoretical calculations and results demonstrate that the synergistic effect of the doped P,which forms active centers in the basal plane of MoS_(2),and S vacancy defects caused by P doping intensifies the intrinsic electronic conductivity and electrocatalytic activity of the catalyst.Density functional theory calculations demonstrate that P optimizes the free energy of the MoS_(2)matrix for hydrogen adsorption,thereby considerably increasing the intrinsic activity of the doped catalyst for the HER compared with that observed from pristine MoS_(2).The enhanced catalytic activity of P-doped MoS_(2)for the OER is attributed to the ability of the doped P which facilitates the adsorption of hydroxyl and hydroperoxy intermediates and reduces the reaction energy barrier.This study provides a new environmentally friendly and convenient solid-phase ion exchange method to improve the electrocatalytic capability of two-dimensional transition-metal dichalcogenides in largescale applications.展开更多
文摘The effects of Ce doping on the structure,optical,oxidation,thermal and magnetic properties of ZnS:Ce nanorods synthesized by a chemical co-precipitation method were reported.The crystalline phase transformation from cubic to hexagonal structure was observed upon doping ZnS with Ce.Magnetic measurements showed the existence of room temperature ferromagnetism in Ce-doped ZnS nanorods.X-ray photoelectron spectroscopic(XPS)measurements provided evidence for Zn-S bonds and oxidation state of Ce in the near-surface region.Raman spectrum provided evidence for the presence of defects as well as hexagonal structure of 5 wt.%Ce doped ZnS nanorods.Ce substitution induced shape evolution was studied by using TEM.DRS spectra further validated the incorporation of Ce^3+ions.The present study reveals that Ce doped ZnS nanorods may find applications in spintronic devices.
基金supported by the National Natural Science Foundation of China(52072196)the Major Basic Research Program of the Natural Science Foundation of Shandong Province(ZR2020ZD09)。
文摘MoS_(2)is a promising electrocatalyst because of its natural abundance and outstanding electrochemical stability.However,the poor conductivity and low activity limit its catalytic performance;furthermore,MoS_(2)is unable to satisfy the requirements of most industrial applications.In this study,to obtain a P-doped MoS_(2)catalyst with S vacancy defects,P is inserted into the MoS_(2)matrix via a solid phase ion exchange at room temperature.The optimal P-doping amount is 11.4 wt%,and the resultant catalyst delivers excellent electrocatalytic properties for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)with the corresponding overpotentials of 93 and 316 mV at 10 mA cm^(-2) in an alkaline solution;these values surpass the overpotentials of most previously reported MoS_(2)-based materials.Theoretical calculations and results demonstrate that the synergistic effect of the doped P,which forms active centers in the basal plane of MoS_(2),and S vacancy defects caused by P doping intensifies the intrinsic electronic conductivity and electrocatalytic activity of the catalyst.Density functional theory calculations demonstrate that P optimizes the free energy of the MoS_(2)matrix for hydrogen adsorption,thereby considerably increasing the intrinsic activity of the doped catalyst for the HER compared with that observed from pristine MoS_(2).The enhanced catalytic activity of P-doped MoS_(2)for the OER is attributed to the ability of the doped P which facilitates the adsorption of hydroxyl and hydroperoxy intermediates and reduces the reaction energy barrier.This study provides a new environmentally friendly and convenient solid-phase ion exchange method to improve the electrocatalytic capability of two-dimensional transition-metal dichalcogenides in largescale applications.
