化学还原法中制备条件对超细银粉形貌的影响

The effect of reaction factors on the morphology of silver particles prepared by chemical reduction method

以AgNO3为原料,抗坏血酸为还原剂,明胶或油酸为高分子保护剂,通过化学还原法制备超细银粉。考察了酸碱度pH值、保护剂种类、催化剂等反应条件对超细银粉形貌的影响。结果表明,反应酸碱度条件对银粉颗粒形貌有决定性影响。当pH值为2时,银粉颗粒为片状;pH值为4时,银粉颗粒为树枝状;pH值为7时,银粉颗粒为类球形。明胶的加入可促进银离子的还原,也更有利于得到形状规则的球形银粉。NH4OH作为催化剂对银粉颗粒的形貌也有一定的影响。

Ultra-fine silver particles were prepared using the chemical reduction reaction of silver nitride with ascorbic acid as reductant gelatin or oleic acid as a protection agent,and ammonia as catalyst.The effect of the reaction factors such as pH value,protective agent,and catalyst on the morphology of silver particles was studied.As the results showing,the effect of pH value on the shape of silver particles is crucial： the flake silver particles can be prepared when pH value is 2;the dendritic silver particles can be prepared when pH value is 4;the quasi-spherical silver particles can be prepared when pH value is 7.Gelatin can promote the nucleation of the metallic silver particles,thus it＇s beneficial to availability of the spherical silver particles.Moreover,as catalyst,ammonia also can influence the shape and size of silver particles.