Cr-Doped Urchin-Like WO3 Hollow Spheres: The Cooperative Modulation of Crystal Growth and Energy-Band Structure for High-Sensitive Acetone Detection. - Qiongling Ding; Yanrong Wang; Pengqian Guo; Jianjun Li; Chen Chen; Ting Wang; Kai Sun; Deyan He (Sensors, 2020)