溶液pH对液相沉积氢氧化镍薄膜的影响

采用液相沉积法在不同pH值溶液中制备了多孔氢氧化镍(Ni(OH)₂)薄膜. 当溶液pH值在7.5～8.8之间变化时, 能在基片上形成均匀连续的由Ni(OH)₂纳米棒搭接组成的多孔薄膜, 主要晶型为β-Ni(OH)₂. 溶液pH值的微小变化会引起薄膜中棒状Ni(OH)₂尺寸的显著改变: 当pH=7.5时, Ni(OH)₂纳米棒的长度约为80nm, 直径约为50nm; 当pH=7.8时, Ni(OH)₂纳米棒的长度增大到180nm, 直径约为60nm; 当pH=8.0时, Ni(OH)₂纳米棒的长度显著增大约为300nm, 直径约为70nm. 然而, 当pH=8.3时, Ni(OH)₂纳米棒的长度减小约为230nm, 直径约为80nm; 当pH=8.8时, 纳米棒长度迅速减小约为110nm, 直径减小约为55nm. 结合Ni(OH)₂成核、生长过程和β-Ni(OH)₂晶体结构特点讨论了溶液pH值对Ni(OH)₂薄膜微观形态的影响机制.

Influence of Solution pH on Nickel Hydroxide Thin Films Prepared by Liquid Phase Deposition

Nickel hydroxide (Ni(OH)₂) thin films were deposited from a variety of solutions with different pH values by liquid phase deposition. Continuous Ni(OH)₂ thin films were obtained within the pH ranging from 7.5 to 8.8. The nucleation and growth process of Ni(OH)₂, and β-Ni(OH)₂ crystallization were used to discuss the influence of solution pH on the microstructures of the Ni(OH)2 films. The thin films are made of Ni(OH)₂ nanorods mainly with β-Ni(OH)₂ crystallinity and there are a lot of open pores between the nanorods in the Ni(OH)₂ films. The dimensions of Ni(OH)₂ nanorods change remarkably with the pH of reactive solutions. When solution’s pH is 7.5, the length of nanorods is about 80nm and the diameter is about 50nm. When solution’s pH increases to 7.8, the length of nanorods increases to about 180nm and the diameter is about 60nm. When solution’s pH increases to 8.0, the length of nanorods sharply increases to about 300nm and the diameter is about 70nm. However, when solution’s pH increases to 8.3, the length of nanorods decreases to about 230nm and the diameter is about 80nm. When solution’s pH increases to 8.8, the length of nanorods sharply decreases to about 110nm and the diameter is about 55nm.