Optical study of redox process of Ag nanoparticles at high temperature
Optical study of redox process of Ag nanoparticles at high temperature
复制标题
DOI：
10.1063/1.1518147
复制
发表时间：
2002-11
影响因子：
3.2
通讯作者：
H. Bi;W. Cai;C. Kan;Lide Zhang;D. Martín;F. Träger
中科院分区：
文献类型：
--
作者：
H. Bi;W. Cai;C. Kan;Lide Zhang;D. Martín;F. Träger
通过将颗粒加载到整体介孔二氧化硅的孔中，对银纳米颗粒的氧化还原进行了光学研究。在不同气氛下退火后测量银纳米颗粒的光吸收。已经发现，如通常预期的那样，在 H2 或 N2 中处理会诱导强烈的表面等离子体共振 (SPR)，但空气退火会导致这种 SPR 消失。在空气和 H2（或 N2）中交替退火会导致 SPR 吸收交替消失和出现，显示出光学变化的可逆性。通过额外考虑颗粒的表面和曲率效应，对银纳米颗粒的氧化进行了热力学分析。与块状金属银不同，银颗粒在 200 °C 以上的空气中稳定且不会被氧化，对于球形银颗粒而言，存在氧化的临界尺寸（例如，500 °C 时为 2 nm）。当粒径小于临界值时，在200℃以上甚至700℃的空气中就会发生氧化...
An optical study of the redox of Ag nanoparticles was carried out by loading the particles into the pores of monolithic mesoporous silica. The optical absorption of silver nanoparticles was measured after annealing in different atmospheres. It has been found that treatment in H2 or N2 induces a strong surface plasmon resonance (SPR) as usually expected, but air-annealing results in disappearance of such SPR. Alternate annealing in air and H2 (or N2) induces alternant disappearance and appearance of the SPR absorption, showing reversibility of optical changes. By additionally considering the surface and curvature effects of a particle, thermodynamic analysis for the oxidation of a Ag nanoparticle was conducted. Unlike bulk metal silver, which is stable and not oxidized in air at above 200 °C, for spherical Ag particle there exists a critical size for the oxidation (say, 2 nm at 500 °C). When the particle size is smaller than the critical value, oxidation could occur in air at above 200 °C and even at 700 °...