The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate the...The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate them to analyze their selectivity in ethanol oxidation reaction(EOR).Here,Pt1Au1alloy supported on the commercial carbon material(Pt_(1)Au_(1)/C)is employed as a typical example to investigate its d-band center shift of surface Pt,and as electrocatalysts to study its selectivity towards EOR.Significantly,a highly reliable in situ Fourier-transform infrared spectroscopy CO-probe strategy is developed to characterize the d-band center shift of surface Pt.The modified electronic effect and site effect of Pt_(1)Au_(1)/C dictated the adsorption configuration of intermediate species and the OH species coverage,thereby influencing its selectivity.More importantly,we developed a universal cyclic voltammetry peak differentiation fitting method as an electrochemical analysis technique to investigate CO_(2)selectivity,which is potentially extendable to other Pt-based electrocatalysts.展开更多
Nano structured LiFexMn1-xPO4 （x=0, 0.2, 0.4） materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials w...Nano structured LiFexMn1-xPO4 （x=0, 0.2, 0.4） materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials were characterized by X-ray diffraction （XRD）, field emission scanning electron microscopy （FESEM） and transmission electron microscopy （TEM）. The electrochemical properties of the materials were investigated by galvanostatic cycling, cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS）. It was found that the materials consisted of nanorods with a diameter of 50 nm and a length of 500 nm. Galvanostatic cycling showed that the capacity of LiMnPO4 could be largely increased by Fe2＋ substitution. At a current rate of C/20, the capacity of the three samples （x=0, 0.2, 0.4） were 47, 107 and 150 mA-h.g-1, respectively. CV result showed that the Fe2＋ substitution could decrease the polarization during charging/discharging, ac- celerating the electrochemical process. EIS result showed that the Fe2＋ substitution could decrease the charge transfer resistance between the electrode and electrolyte, as well as increase the Li-ion diffusion coefficient in the bulk material, resulting in an improved electrochemical performance.展开更多
基金granted by the National Natural Science Foundation of China(22172134,22288102,22279011)Fundamental Research Funds for the Central Universities(2022CDJXY-003)。
文摘The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate them to analyze their selectivity in ethanol oxidation reaction(EOR).Here,Pt1Au1alloy supported on the commercial carbon material(Pt_(1)Au_(1)/C)is employed as a typical example to investigate its d-band center shift of surface Pt,and as electrocatalysts to study its selectivity towards EOR.Significantly,a highly reliable in situ Fourier-transform infrared spectroscopy CO-probe strategy is developed to characterize the d-band center shift of surface Pt.The modified electronic effect and site effect of Pt_(1)Au_(1)/C dictated the adsorption configuration of intermediate species and the OH species coverage,thereby influencing its selectivity.More importantly,we developed a universal cyclic voltammetry peak differentiation fitting method as an electrochemical analysis technique to investigate CO_(2)selectivity,which is potentially extendable to other Pt-based electrocatalysts.
基金supported by Zijin Program of Zhejiang University, Chinathe Fundamental Research Funds for the Central Universities (No. 2010QNA4003)+3 种基金the Ph.D.Programs Foundation of Ministry of Education of China(No. 20100101120024)the Foundation of Education Office of Zhejiang Province, China (No. Y201016484)the Qianjiang Talents Project of Science Technology Department of Zhejiang Province, China (No. 2011R10021)the National Natural Science Foundation of China (No.51101139)
文摘Nano structured LiFexMn1-xPO4 （x=0, 0.2, 0.4） materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials were characterized by X-ray diffraction （XRD）, field emission scanning electron microscopy （FESEM） and transmission electron microscopy （TEM）. The electrochemical properties of the materials were investigated by galvanostatic cycling, cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS）. It was found that the materials consisted of nanorods with a diameter of 50 nm and a length of 500 nm. Galvanostatic cycling showed that the capacity of LiMnPO4 could be largely increased by Fe2＋ substitution. At a current rate of C/20, the capacity of the three samples （x=0, 0.2, 0.4） were 47, 107 and 150 mA-h.g-1, respectively. CV result showed that the Fe2＋ substitution could decrease the polarization during charging/discharging, ac- celerating the electrochemical process. EIS result showed that the Fe2＋ substitution could decrease the charge transfer resistance between the electrode and electrolyte, as well as increase the Li-ion diffusion coefficient in the bulk material, resulting in an improved electrochemical performance.
