Hierarchical WO₃ nanomesh, assembled from single-crystalline WO₃ nanowires, is prepared via a hydrothermal method using thiourea (Tu) as the morphology-controlling agent. Formation of the hierarchical architecture comprising of WO₃ nanowires takes place via Ostwald ripening mechanism with the growth orientation. The sensor based on WO₃ nanomesh has good electrical conductivity and is therefore suitable as NO₂ sensing material. The WO₃ nanomesh sensor exhibited high response, short response and recovery time, and excellent selectivity towards ppb-level NO₂ at low temperature of 160 ℃. The superior gas performance of the sensor was attributed to the high-purity hexagonal WO₃ with high specific surface area, which gives rise to enhanced surface adsorption sites for gas adsorption. The electron depletion theory was used for explaining the NO₂-sensing mechanism by the gas adsorption/desorption and charge transfer happened on the surface of WO₃ nanomesh.

Studying on the anode materials with high energy densities for next-generation lithium-ion batteries (LIBs) is the key for the wide application for electrochemical energy storage devices. Ti-based compounds as promising anode materials are known for their outstanding high-rate capacity and cycling stability as well as improved safety over graphite. However, Ti-based materials still suffer from the low capacity, thus largely limiting their commercialized application. Here, we present an overview of the recent development of Ti-based anode materials in LIBs, and special emphasis is placed on capacity enhancement by rational design of hybrid nanocomposites with conversion-/ alloying-type anodes. This review is expected to provide a guidance for designing novel Ti-based materials for energy storage and conversion.