This paper presents a new method of surface modification on LaNi5 hydr ogen storage alloy. The hydrogen alloy was treated in the acid CuSO4 solution co ntaining HF. The effect of HF on surface state of alloy was studi...This paper presents a new method of surface modification on LaNi5 hydr ogen storage alloy. The hydrogen alloy was treated in the acid CuSO4 solution co ntaining HF. The effect of HF on surface state of alloy was studied and the elec trochemical properties of modified alloy were investigated. Electrochemical impe dance spectra (EIS) was also applied to analyze the resistance property of alloy electrode after modification. SEM and XRD results showed that HF had corrosive effect on hydrogen alloy, which help copper grain to precipitate on alloy surfac e. EIS analysis showed that modified alloy had lower contact resistance and elec trochemical polarization, which resulted in a higher conductivity and electroche mical activation. Electrochemical testing showed modified alloy had better activ ation behavior and excellent large current discharge ability. Thus it could well satisfy the requirement of the application as power sources on electric vehicle s.展开更多
The Pd-Pb catalyst supported on Al2O3 was prepared by the two-step impregnation method.The oxidative esterification of methacrolein （MAL） to methyl methacrylate （MMA） was carried out in a stainless bubble autoclav...The Pd-Pb catalyst supported on Al2O3 was prepared by the two-step impregnation method.The oxidative esterification of methacrolein （MAL） to methyl methacrylate （MMA） was carried out in a stainless bubble autoclave over the catalyst.The influences of the reaction conditions on catalytic activity were investigated in detail.The optimal reaction conditions were as follows: T=80℃, P=0.3 MPa, methanol∶MAL=8∶1 （ molar ratio ）, catalyst mass concentration in the reaction system 3.84%, pH of the reaction system 7—8, oxygen flux rate 30 ml·min -1 .Under the above conditions,MAL conversion and MMA selectivity reached 91% and 84%, respectively.The catalyst was recycled for seven times and still kept good selectivity.展开更多
文摘This paper presents a new method of surface modification on LaNi5 hydr ogen storage alloy. The hydrogen alloy was treated in the acid CuSO4 solution co ntaining HF. The effect of HF on surface state of alloy was studied and the elec trochemical properties of modified alloy were investigated. Electrochemical impe dance spectra (EIS) was also applied to analyze the resistance property of alloy electrode after modification. SEM and XRD results showed that HF had corrosive effect on hydrogen alloy, which help copper grain to precipitate on alloy surfac e. EIS analysis showed that modified alloy had lower contact resistance and elec trochemical polarization, which resulted in a higher conductivity and electroche mical activation. Electrochemical testing showed modified alloy had better activ ation behavior and excellent large current discharge ability. Thus it could well satisfy the requirement of the application as power sources on electric vehicle s.
文摘The Pd-Pb catalyst supported on Al2O3 was prepared by the two-step impregnation method.The oxidative esterification of methacrolein （MAL） to methyl methacrylate （MMA） was carried out in a stainless bubble autoclave over the catalyst.The influences of the reaction conditions on catalytic activity were investigated in detail.The optimal reaction conditions were as follows: T=80℃, P=0.3 MPa, methanol∶MAL=8∶1 （ molar ratio ）, catalyst mass concentration in the reaction system 3.84%, pH of the reaction system 7—8, oxygen flux rate 30 ml·min -1 .Under the above conditions,MAL conversion and MMA selectivity reached 91% and 84%, respectively.The catalyst was recycled for seven times and still kept good selectivity.
