题目：

Reduced GeO₂ Nanoparticles: Electronic Structure of a Nominal GeOx Complex and Its Stability under H₂ Annealing

作者：

Jia Zhao, Linju Yang, John A. McLeod & Lijia Liu

单位：

Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano and Soft Materials (FUNSOM),

Soochow University-Western University Center for Synchrotron Radiation Research, Soochow University, Suzhou, Jiangsu, 215123 China.

摘要：

A nominal GeOx (x ≤  2) compound contains mixtures of Ge, Ge suboxides, and GeO₂, but the detailed composition and crystallinity could vary from material to material. In this study, we synthesize GeOx nanoparticles by chemical reduction of GeO₂, and comparatively investigate the freshly prepared sample and the sample exposed to ambient conditions. Although both compounds are nominally GeOx, they exhibit different X-ray diffraction patterns. X-ray absorption fie structure (XAFS) is utilized to analyse the detailed structure of GeOx. We find that the two initial GeOx compounds have entirely different compositions: the fresh GeOx contains large amorphous Ge clusters connected by GeOx, while after air exposure; the Ge clusters are replaced by a GeO₂-GeOx composite. In addition, the two GeOx products undergo different structural rearrangement under H₂ annealing, producing different intermediate phases before ultimately turning into metallic Ge. In the fresh GeOx, the amorphous Ge remains stable, with the GeOx being gradually reduced to Ge, leading to a final structure of crystalline Ge grains connected by GeOx. The air-exposed GeOx on the other hand, undergoes a GeO₂→GeOx→Ge transition, in which H₂ induces the creation of oxygen vacancies at intermediate stage. A complete removal of oxides occurs at high temperature.

影响因子：

5.578

分区情况：

2区

链接：

http://www.nature.com/articles/srep17779