聚乙二醇对二氧化铅电沉积机理的影响

Effects of PEG on PbO_2 electrodeposition mechanism

为研究有机添加剂聚乙二醇(PEG)对电沉积PbO_2的影响,在含有PEG的硝酸盐体系中,制备了Ti/PbO_2电极材料。利用XRD,SEM,研究了PbO_2电极材料的物相组成及镀层形貌;利用循环伏安法和计时电流法,结合Scharifker-Hill(SH)三维成核模型,研究了PEG对PbO_2电沉积行为及电结晶动力学过程的影响。结果表明:制备的镀层为β-PbO_2,PEG可改变晶面择优生长取向,但不改变晶型;PbO_2晶粒的长大遵循"广义电化学综合生长机理",PEG可细化PbO_2晶粒,消除镀层缺陷;PEG不仅提高了PbO_2在基体上的沉积量,而且加强了PbO_2自身的催化效果,促进其进一步沉积;PEG的加入提高了Pb^(2+)的扩散系数,有利于Pb^(2+)向电极界面的扩散;PEG使PbO_2电结晶由连续成核转变为瞬时成核,同时,也使二氧化铅形核速率加快,但其成核量却显著减少。

Abstract：The Ti/PbO2anodes were prepared in nitrate solution in the presence of PEG to study the effects of PEG on PbO2 electro-deposition. The XRD and SEM were used to analyze the phase composition and the microstructure of PbO2 ;The effects of PEG on PbO2 electrodeposition behavior and kinetics process of PbO2 electrocrystallization were studied by cyclic voltammetry, chronoamper - ometry and Scharifker-Hills（SH） mechanism. The results indicate that： The coating was composed by p-PbO2, and PEG did not change the crystal form but led to perferred growth of PbO2 crystal face ; the grow t h of Pb0 2 crystals w e r e followed Generalized E l e c -trochemical Aggregative Growth Mechanism, and PEG can make the PbO2 crystal grains refined, besides, remove the flaws on coating surface;Not only PEG incresed the quantity of electrodeposition PbO2 on Pt substrates,but also reinforce the self-catalytic ability of PbO2,and promoted the further electrodeposition of PbO2;The diffusion coefficient of Pb^2＋ in solution was increased by PEG,which was favorable for diffusing of Pb^2＋ towards electrode. The PbO2 The nucleation mode shifted from progressive nucleation towards in-stantaneous in the presence of PEG, moreover, the PbO2 nucleation rate increased and the quantity of nucleation was reduced by PEG