Shunhang Wei,Rong Wu,Xiaoxiang Xu,Jikang Jian,Haixia Wang,Yanfei Sun
Black core-shelled anatase titania were successfully prepared using a simple one-step synthetic method by calcining colloid titania precursor in N 2 flow under atmospheric pressure. The physicochemical properties of the as-prepared samples were characterized by various techniques such as X-ray diffraction, high resolution transmission electron microcopy, etc. The samples demonstrate a unique core-shelled structure and electron paramagnetic resonance spectra reveal the presence of high concentration of Ti 3+ and oxygen vacancies at the surface, which accounts for their black appearance. A possible mechanism for the formation of such core–shell structure is proposed based on the results (X-ray photoelectron spectra, etc) of products prepared under different ration between urea and hydrochloric acid. Ethanol absolute is found to have critical effect in preventing phase transition of titania (from anatase to rutile) upon elevated temperatures. The black appearance of the sample powder (high visible light absorption) as well as slow electron/hole recombination rate after introducing oxygen vacancies/N species signify the core-shelled anatase titania as an efficient visible light active photocatalyst.
In this study, a one-pot sintering process incorporating sol–gel preparation route and in-situ carbon coating was proposed for the synthesis of carbon-coated nanosized LiTi 2 (PO 4 ) 3 . Experimental results show that the prepared LiTi 2 (PO 4 ) 3 particles are of high crystallinity and well-coated by turbostratic carbon. Attributed to nanosized particles and enhanced conductivity provided by turbostratic carbon coating, the carbon-coated LiTi 2 (PO 4 ) 3 showed high rate performance and good cycling life in aqueous electrolyte. Particularly, the carbon-coated LiTi 2 (PO 4 ) 3 exhibited initial specific capacities of 103 and 89 mAh g −1 , and retained 80.6% and 97% of the initial capacities after 120 cycles at 1C and 10C in aqueous electrolyte, respectively. The high rate performance and good cycling life of carbon-coated LiTi 2 (PO 4 ) 3 in aqueous electrolyte reveal its potential as negative electrode in aqueous lithium-ion batteries for electric vehicles and industrial-scale energy storage systems .
危险品化学品经营许可证（带存储）