ZrOCl2掺杂的磷硅酸盐凝胶的机械化学合成

摘要

纯磷硅酸盐干凝胶在潮湿环境下存放会使磷酸从中析出,导致其质子电导率显著下降.为此,人们通常采用化学改性处理的方式以解决其化学耐久性差的问题.利用ZrOCl2·8H2O通过溶胶凝胶法对磷硅酸盐进行掺杂,我们发现掺杂量为0.97%时,所得凝胶的质子电导率最高.基于此,本文利用高能球磨技术研究了磷硅酸盐凝胶的ZrOCl2掺杂.研究结果表明:机械研磨能够提高原料混合物的质子电导率,当研磨时间为10 h时,所得材料的质子电导率最大,σ130=2.4 S·m-1.这一数值与利用溶胶-凝胶法制备的同样化学成分的样品相同.但前者的质子传导激活能高于后者,造成这一差别的主要原因是两者内部的组织结构存在一定差别.31P NMR(Nuclear Magnetic Resonance核磁共振)谱测试结果表明:机械研磨处理的样品(尤其MM10 h)化学耐久性较好.%Proton conductivity of phosphosilicate gels was greatly decreased due to precipitation of H3PO4 during holding under humid conditions.Therefore, modification to the gels by doping was frequently adopted for the purpose of increasing their chemical durability.Our researches revealed that doping of ZrOCl2 could improve proton conductivity of the phosphosilicate gel by sol-gel process, and that maximum proton conductivity was reached at a ZrOCl2·8H2O content of 0.97％.Based on this, this paper reported preparation of the ZrOCl2-doped phosphosilicate gel by mechanical milling.Our results proved that mechanical milling could increase proton conductivity of the mixture of starting materials, and that the maximum proton conductivity, σ130=2.4 S·m-1, was obtained at the milling time of 10 h.This value was the same as that of the sol-gel-prepared one with same compositions.However, proton conduction activation energy of the former was higher than that of the latter, main reason for this was that there existed some difference in microstructure.31P NMR measurements indicated that the ball-milled samples, especially the MM10 h one, showed good chemical durability.