Abstract Control of crystal growth leads to highly functional materials with desired morphologies. In this study, the relationship between select additives and the crystal growth of rutile-type titania under hydrothermal conditions using α-hydroxy acids, carboxylic acids, or alcohols as additives was systematically investigated. Without additives, rod-like rutile crystals with average dimensions of 295 nm × 67 nm were formed. Acceleration of the crystal growth was observed and the aspect ratios of the resulting rod-like crystals were found to increase in the presence of the additives. Alcohols promoted crystal growth along the c-axis, but not in the direction to perpendicular to [001]. Carboxylic acids accelerated the overall crystal growth and this increase was more enhanced along the c-axis than that along others. Both effects were observed using α-hydroxy acids. In addition, the present results implied that the size of the hydrocarbon groups in alcohols and α-hydroxy acids appeared to be related to the acceleration of crystal growth along the c-axis. Hydroxy groups may reduce the surface energy of the crystal facets perpendicular to the c-axis by their adsorption on those facets, resulting in the formation of rod-like crystals with high aspect ratio.

中文翻译：

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羟基和羧基对水热条件下金红石型二氧化钛各向异性生长的影响

摘要 晶体生长的控制导致具有所需形态的高功能材料。在这项研究中，系统研究了选择添加剂与使用 α-羟基酸、羧酸或醇作为添加剂的水热条件下金红石型二氧化钛晶体生长之间的关系。在没有添加剂的情况下，形成了平均尺寸为 295 nm × 67 nm 的棒状金红石晶体。观察到晶体生长加速并且发现所得棒状晶体的纵横比在添加剂存在下增加。醇促进沿 c 轴的晶体生长，但不促进垂直于 [001] 的方向。羧酸加速了整体晶体的生长，这种增加沿着 c 轴比沿着其他轴增加得更多。使用α-羟基酸观察到这两种效果。此外，目前的结果表明醇和α-羟基酸中烃基的大小似乎与沿 c 轴的晶体生长加速有关。羟基可以通过吸附在垂直于 c 轴的晶面上降低表面能，导致形成具有高纵横比的棒状晶体。