High temperature oxidation event of gelatin nanoskin-coated copper fine particles observed by in situ TEM

Takashi Narushima,Hiroki Tsukamoto,Tetsu Yonezawa

doi:10.1063/1.4759498

Abstract

Metallic copper fine particles were prepared using CuO slurry by hydrazine reduction in the presence of gelatin. To observe a behavior of these particles at high temperature, in situ heating TEM observations were carried out. Oxygen gas was introduced and the pressure of the TEM column was kept at 10−3 Pa, corresponding the pressure around the sample at 10−1 Pa. The gelatin, which acts as a protective nanoskin on the particle surface was gradually decomposed. Around approximately 140 °C, it was observed that Cu2O dots formed on the surface of the copper particle. This result is well consistent with the behavior of the TG-DTA curve of the copper fine particles under ambient conditions, and provides key information of oxidative behavior of copper fine particles.

Highlights

INTRODUCTIONMetal nano- and fine particles were widely used for various fields of science and technology, because of their unique physical and chemical properties depending on their size and shapes.[1,2,3,4]
Metal nano- and fine particles were widely used for various fields of science and technology, because of their unique physical and chemical properties depending on their size and shapes.[1,2,3,4]In particular, copper attracts much attention because of its high electro-conductivity, relatively low cost, and its many prospects
In our previous report,[17] copper fine particles were prepared from CuO in ethanol/water mixed solvent (water : ethanol = 1 : 1) in order to avoid the formation of foams during reduction and obtained particles were collected by suction filtration

Summary

INTRODUCTION

Metal nano- and fine particles were widely used for various fields of science and technology, because of their unique physical and chemical properties depending on their size and shapes.[1,2,3,4]. We firstly report the direct observation of the oxidation behavior of gelatinstabilized copper fine particles, which were prepared by the reduction of CuO by hydrazine, with which we obtained in situ heating TEM under 10−3 Pa level oxygen partial pressure. This was higher than the previous reports. We compared the oxidation phenomenon with the TG-DTA results at ambient condition

Materials

Synthesis of copper fine particles

Characterization

TG-DTA

In situ heating TEM observation

CONCLUSIONS