甘油基电解液中阴离子对阳极氧化TiO_2纳米管生长的影响

Effect of Anions on the Electrochemical Formation of TiO_2 Nanotube Arrays in a Glycerol Based Electrolyte

在NH4F-甘油-水电解液中,采用阳极氧化法,在纯Ti基底上制备了高度取向的TiO2纳米管阵列,考察了阴离子种类、阳极氧化时间及NaAc浓度对纳米管阵列生长的影响.结果表明,TiO2纳米管的生长速率和长度强烈依赖于阴离子的种类和浓度.NaNO3和NaCl的加入能增大阳极氧化时的电流密度,提高TiO2纳米管底部的腐蚀速率,提高管的生长速率及增加管的长度;而NaAc的加入更大程度上抑制了已生成的TiO2纳米管顶部的溶解,提高了纳米管的净生长速率,得到较长的纳米管阵列.

The formation of titania nanotubes was achieved by electrochemical anodization in glycerol based electrolytes. We investigated the effect of three anionic species, anodic time and NaAc concentration on the formation of TiO2 nanotubes. The choice of anion was found to be a key parameter influencing both the nanotube growth rate and the resultant nanotube length. Longer tube lengths were obtained by adding NaNO3 and NaCl, by increasing the current density and by increasing the electrochemical etching rate at tube＇s bottom. The current density and the electrochemical etching rate at the tube＇s bottom decreased with added NaAc. Electrolytes with added NaAc were much more efficient at producing longer nanotubes, by effectively slowing the chemical dissolution rate at the top of the tube.