银纳米线的制备及电催化还原氧性能研究

Synthesis of Silver Nanowires and Studies on its Electrocatalytic Activity of Oxygen Electroreduction

分别以聚乙烯基吡咯烷酮(PVP),乙二醇作为软模板和还原剂,采用不同晶种(AgCl、Ag)快速合成了银纳米线.通过SEM和TEM表征,证明合成银纳米线材料形貌均一,颗粒含量很少.并且发现以AgCl为晶种合成的银纳米线长径比为200左右(SNWH),而以Ag为晶种合成的长径比为30左右(SNWL).以银纳米线作为电催化氧气还原反应(ORR)的催化剂.通过循环伏安法测定,发现银纳米线对氧还原具有显著的活性,反应起始还原电压为-0.17 V左右,还原峰电压为-0.45V左右,并且反应受O2扩散的控制.研究表明两种长径比的银纳米线均对醇类有一定的抵抗力.如对于SNWH,当甲醇含量为2.0 mol/L或乙醇含量为0.5 mol/L时,电催化ORR仍具有较高的活性.比较不同的醇类对于银纳米线电催化ORR,发现醇类对反应的影响的顺序如下:甲醇<乙醇<异丙醇.

The paper focuses on the easy and fast synthesis of silver nanowires,and the catalysis activity of for oxygen electroreduction reaction.AgCl,PVP,and ethylene glycol（EG） were used as soft-template,and reducing agent,respectively.And different aspect ratios of silver nanowires were synthesized with different seeds（AgCl and Ag）.By the characterization of SEM,TEM and others,a large quantity of nanowire with a little of nanoparticles was achieved.It was found the aspect ratios of silver nanowires were about 200（SNWH） with AgCl,and the others were 30（SNWL） with Ag.It was found the catalysis activity of silver nanowires was obviously and the onset reduction potentials at about-0.17 V and the reduction peaks at about-0.45 V were observed from cyclic voltammetry curves.The current values of reduction peaks on SNWH and SNWL were 3.01×10-5A and 2.42×10-5A,and the slope data of Tafel curves were 94 and 96 mV/dec respectively.Those above results implied that the activity of SNWH was better than that of SNWL for ORR.The difference of the activity might be due to the different specific surface area of both silver nanowires.The result indicated that both silver nanowires were alcohol-tolerant for ORR.The effects of alcohol on the loss of ORR activity for silver nanowires follow the order： iso-propanol ethanol methanol.