Revealing Dominant Oxidative Species in Reactive Oxygen Species-Driven Rapid Chemical Etching.

Reactive oxygen species (ROS) widely participate in a variety of chemical reactions in biological and chemical applications. However, due to the extremely short lifetime of most ROS, conventional ROS-detecting techniques cannot show real-time dynamic changes of ROS-driven chemical reactions and identify the actual role of individual reactive species in these reactions. Herein, using in situ liquid cell TEM complemented by ex situ experiments, we directly visualize ROS-driven rapid etching of Prussian bule (PB) in real time and identify the dominant reactive species in etching processes. The results reveal that highly oxidative •OH is the dominant reactive radical in ROS-driven rapid chemical etching and hollow mesoporous PB nanoparticles can be synthesized on a minute-level time scale via •OH-dominated rapid etching. This work provides insight into ROS-related oxidation, which can continuously improve our understanding of ROS chemistry and make ROS more widely applicable in advanced chemical etching.

Controllable fabrication of hollow In2O3 nanoparticles by electron beam irradiation.

A growth strategy is presented for controllable fabrication of hollow In2O3 nanoparticles (NPs) via oxidation of In nanocrystals under electron beam irradiation. The morphology of the NPs can be tailored by changing the electron beam energy and current density. Yolk-shell NPs are preferentially formed under 200 keV electron beam irradiation, while hollow NPs are preferentially formed at 300 keV. This work confirms that electron beam irradiation is a valuable method for the engineering and modification of nanomaterials.

In Situ Atomic-Scale Observation of Silver Oxidation Triggered by Electron Beam Irradiation.

Understanding the mechanism of metal oxidation processes is critical for maintaining the desired properties of metals and catalysts, as well as for designing advanced materials. In this work, we investigate the electron beam induced oxidation of silver using in situ transmission electron microscopy. The additions of Ag-O columns on {111} and {110} planes were captured with atomic resolution. Interestingly, oscillatory growth on {110} planes was observed, which resulted from the double effect of electron beam irradiation. It was found that not only thermodynamic factors but also kinetic factors played significant roles in morphology evolutions. These results can facilitate the fundamental understanding of the oxidation process of Ag and provide a promising approach for the fabrication of desired nanostructures.