SCIENCE CHINA Materials, Volume 61, Issue 6: 869-877(2018) https://doi.org/10.1007/s40843-017-9183-2

A simple green approach to synthesis of sub-100 nm carbon spheres as template for TiO2 hollow nanospheres with enhanced photocatalytic activities

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  • ReceivedNov 7, 2017
  • AcceptedDec 15, 2017
  • PublishedJan 17, 2018


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.

Funded by

the Foundation for the Author of National Excellent Doctoral Dissertation of China(201335)

the National Program for Support of Top-notch Young Professionals and the ‘‘Fundamental Research Funds for the Central Universities’’.


The work was supported by the National Natural Science Foundation of China (51672210, 51323011 and 51236007), and the Natural Science Foundation of Shaanxi Province (2014KW07-02). Shen S was supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China (201335), the National Program for Support of Top-notch Young Professionals and the ‘‘Fundamental Research Funds for the Central Universities’’.

Interest statement

The authors declare no conflict of interest.

Contributions statement

Shen S and Feng X conceived the idea and supervised the project. Tan Y carried out the sample synthesis, characterizations and photocatalysis measurements. Wei D operated the SPV. Tang H conducted the TGA tests. Tan Y, Liu M and Shen S wrote the paper. All the authors discussed the results and revised the manuscript.

Author information

Yubo Tan is currently a PhD student of IRCRE, State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy & Power Engineering, Xi’an Jiaotong University. Her research interests focus on nanoparticles for photocatalytic water splitting. From Oct. 2017 to Sept. 2019, she is a visiting scholar at the University of California, Riverside, USA, under the supervision of Prof. Yadong Yin for 2 years awarded by the China Scholarship Council (CSC).

Xinjian Feng received his PhD at the Institute of Chemistry, Chinese Academy of Sciences in 2006, and then he continued his scientific research at the University of Erlangen Nurnberg in Germany (2006–2007), Pennsylvania State University (2007–2012) and Chinese Academy of Sciences (2012–2015). In 2011, he was selected as the member in the first batch of ‘‘the Thousand Talents Plan’’ of the Central Organization Department. His research focuses on the designation and preparation of the electrode material and micro-nano structure; the transmission performance of electron and material in the surface and inside of electrode; the electrode materials in solar conversion and biosensing devices. So far, nearly 50 academic papers and research reviews have been published, including Angew. Chem. Int. Ed., Nano Lett., Adv. Mater., J. Am. Chem. Soc., etc. with more than 5,000 citations.

Shaohua Shen received his PhD at Xi’an Jiaotong University in 2010, and then he continued his postdoctoral at the University of California at Berkeley from November, 2011 to October, 2012. He is currently a full professor of IRCRE, the State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy & Power Engineering, Xi’an Jiaotong University. He was the winner of the National Excellent Doctoral Dissertation, 2012. He has published more than 80 papers in Chem. Rev., Adv. Mater., Nature Photon., etc., and received more than 6,800 citations. His research interests include the synthesis of nanomaterials and development of devices for photocatalytic and photoelectrochemical solar energy conversion.


Supplementary information

Supporting data are available in the online version of the paper.


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  • Figure 1

    (a, b) Typical FESEM and TEM images of the CSs obtained via HTC method. Average diameter of CSs obtained via the defined typical synthesis process with (c) glucose concentrations varying from 0.01 to 0.16 g mL−1, (d) pH varying from 2.5 to 10.5, (e) reaction temperatures varying from 180 to 200°C, and (f) reaction times varying from 2 to 8 h. The scale bar in (a) and (b) is 100 nm.

  • Figure 2

    (a) FTIR patterns of the CSs obtained with different initial pH values (from 2.5 to 10.5); concentration: 0.08 g mL−1; reaction time: 4 h; temperature: 180°C. (b) TGA curves of CSs performed in air, heated to 600°C.

  • Figure 3

    (a) Schematic illustration of the preparation of HTNSs. (b, e and h) FESEM images of CSs with an average size of 40, 140 and 450 nm, respectively. (c, f and i) FESEM images of corresponding HTNSs (HTNS-40, HTNS-140, HTNS-450, respectively), using CSs in different particle sizes as templates. (d, g and j) TEM images of corresponding HTNSs (HTNS-40, HTNS-140, HTNS-450, respectively), using CSs in different particle sizes as templates. (k) Typical XRD patterns of HTNSs synthesized with CSs as templates. Inset shows typical XRD patterns of CSs/TiO2 core-shell structures. The scale bar in (b to g) is 100 nm, (h and i) is 1 um, (j) is 500 nm, respectively.

  • Figure 4

    SPV of different structure of photocatalysts.

  • Figure 5

    Photocatalytic performances of HTNSs in different sizes, solid TiO2 nanoparticles and P25. (a) Time courses of photocatalytic hydrogen production, (b) photocatalytic hydrogen production rates.

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