Optical measurements of oxidation behavior of silver nanometer particle within pores of silica host
Optical measurements of oxidation behavior of silver nanometer particle within pores of silica host
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DOI：
10.1063/1.366888
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发表时间：
1998-02-01
影响因子：
3.2
通讯作者：
Zhang, LD
中科院分区：
文献类型：
--
作者：
Cai, WP;Zhong, HC;Zhang, LD
用光吸收法研究了银(Ag)纳米粒子(直径约3 nm)在环境空气(298K)中的氧化行为。热力学分析表明，银纳米粒子在室温下可以在空气中被氧化。暴露在空气中会导致吸收边随时间蓝移，这归因于银纳米粒子的表面氧化。在此基础上，我们提出了一种新的方法来研究纳米银的氧化过程。进一步的实验表明，在空气中，在室温下，氧化发生在银颗粒的表层，形成致密的Ag2O薄膜。一旦形成致密的薄膜，进一步的氧化就会受到抑制。空气中的高相对湿度会导致表面快速氧化。在室温相对湿度为80%的空气中，2小时即可形成致密的薄膜。
The oxidation behavior of silver (Ag) nanometer particles (about 3 nm in diameter) within pores of a silica host in ambient air (298 K) was investigated from optical absorption measurements. Thermodynamic analysis indicates that Ag nanoparticles can be oxidized in air at room temperature. Exposure to air results in a blueshift of the absorption edge with time, which is attributed to the surface oxidation of Ag nanoparticles. On this basis, we present a new method to investigate the oxidation process of Ag nanoparticles. Further experiments show that in air at room temperature oxidation occurs in surface layers of Ag particles in the form of a dense Ag2O film. Once the dense film is formed, further oxidation is restrained. A high relative humidity in the air results in fast surface oxidation. In air with a relative humidity 80% at room temperature, a dense film can be formed in 2 h. When the relative humidity is