Wuhan University of Technology

About: Wuhan University of Technology is a education organization based out in Wuhan, China. It is known for research contribution in the topics: Microstructure & Photocatalysis. The organization has 40384 authors who have published 36724 publications receiving 575695 citations. The organization is also known as: WUT.

The stability of P2-layered sodium transition metal oxides in ambient atmospheres

Abstract: Air-stability is one of the most important considerations for the practical application of electrode materials in energy-harvesting/storage devices, ranging from solar cells to rechargeable batteries. The promising P2-layered sodium transition metal oxides (P2-NaxTmO2) often suffer from structural/chemical transformations when contacted with moist air. However, these elaborate transitions and the evaluation rules towards air-stable P2-NaxTmO2 have not yet been clearly elucidated. Herein, taking P2-Na0.67MnO2 and P2-Na0.67Ni0.33Mn0.67O2 as key examples, we unveil the comprehensive structural/chemical degradation mechanisms of P2-NaxTmO2 in different ambient atmospheres by using various microscopic/spectroscopic characterizations and first-principle calculations. The extent of bulk structural/chemical transformation of P2-NaxTmO2 is determined by the amount of extracted Na+, which is mainly compensated by Na+/H+ exchange. By expanding our study to a series of Mn-based oxides, we reveal that the air-stability of P2-NaxTmO2 is highly related to their oxidation features in the first charge process and further propose a practical evaluating rule associated with redox couples for air-stable NaxTmO2 cathodes. Air-stability is a critical challenge faced by layered sodium transition metal oxide cathodes. Here, the authors depict a general and in-depth model of the structural/chemical evolution of P2-type layered oxides in air and propose an evaluation rule for the air-stability of layered sodium cathodes.

Single‐Component TiO2 Tubular Microengines with Motion Controlled by Light‐Induced Bubbles

Abstract: In this work, light-controlled bubble-propelled single-component metal oxide tubular microengines have for the first time been demonstrated. For such a simple single-component TiO2 tubular microengine in H2O2 aqueous solution under UV irradiation, when the inner diameter and length of the tube are regulated, the O2 molecules will nucleate and grow into bubbles preferentially on the inner concave surface rather than on the outer surface, resulting in a vital propulsion of the microengine. More importantly, the motion state and speed can be modulated reversibly, fast (the response time is less than 0.2 s) and wirelessly by adjusting UV irradiation. Consequently, the as-developed TiO2 tubular microengine promises potential challenged applications related to photocatalysis, such as "on-the-fly" photocatalytic degradation of organic pollutes and photocatalytic inactivation of bacteria due to the low cost, single component, and simple structure, as well as the facile fabrication in a large-scale.