Carbon spheres（CSs） have attracted great attention given their wide applications in bio-diagnostics, photonic band-gap crystals and drug delivery, etc. The morphology and size of CSs greatly affect their performance...Carbon spheres（CSs） have attracted great attention given their wide applications in bio-diagnostics, photonic band-gap crystals and drug delivery, etc. The morphology and size of CSs greatly affect their performances and applications. Herein, we report a green and catalyst-free hydrothermal carbonization（HTC） method to synthesize CSs with glucose as carbon precursor. The diameter of CSs can be tuned within a wide range from 450 to 40 nm by controlling the glucose concentration, reaction time and temperature.Using the obtained CSs as template, hollow TiO2 nanospheres（HTNSs） with controllable diameters are prepared via a sol-gel method. As photocatalysts for hydrogen generation, the photoactivity of the HTNSs shows strong dependence upon size,and is much higher than that of solid TiO2. With particle size decreasing, the photoactivity of the obtained HTNSs gradually increases. Without any co-catalyst, the highest photocatalytic hydrogen generation activity is obtained with HTNSs of 40 nm in diameter, which exceeds that of solid TiO2 and commercial P25 by 64 times and 3 times, respectively.展开更多
基金supported by the National Natural Science Foundation of China (51672210, 51323011 and 51236007)the Natural Science Foundation of Shaanxi Province (2014KW07-02)+2 种基金supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China (201335)the National Program for Support of Top-notch Young Professionalsthe ‘‘Fundamental Research Funds for the Central Universities’’
文摘Carbon spheres（CSs） have attracted great attention given their wide applications in bio-diagnostics, photonic band-gap crystals and drug delivery, etc. The morphology and size of CSs greatly affect their performances and applications. Herein, we report a green and catalyst-free hydrothermal carbonization（HTC） method to synthesize CSs with glucose as carbon precursor. The diameter of CSs can be tuned within a wide range from 450 to 40 nm by controlling the glucose concentration, reaction time and temperature.Using the obtained CSs as template, hollow TiO2 nanospheres（HTNSs） with controllable diameters are prepared via a sol-gel method. As photocatalysts for hydrogen generation, the photoactivity of the HTNSs shows strong dependence upon size,and is much higher than that of solid TiO2. With particle size decreasing, the photoactivity of the obtained HTNSs gradually increases. Without any co-catalyst, the highest photocatalytic hydrogen generation activity is obtained with HTNSs of 40 nm in diameter, which exceeds that of solid TiO2 and commercial P25 by 64 times and 3 times, respectively.
