Electronic Supplementary Information
Fabrication and Photocatalytic Activities of SrTiO3
Nanofibers by Sol-Gel Assisted Electrospinning
Guorui Yang1, Wei Yan,1,2* Jianan Wang1, Qian Zhang1 and Honghui Yang1,
1
Department of Environmental Science and Engineering, Xi’an Jiaotong University, Xi’an
710049, China
2
Suzhou Academy of Xi’an Jiaotong University, Suzhou 215123, China
Scheme S1. The schematic setup of the photocatalytic reactor for hydrogen production.
Scheme S2. Schematic illustration of the mechanism in photocatalytic hydrogen production using
the nanofibers and nanoparticles.
The advantages of nanofibers over nanoparticles during the photocatalytic process have been
shown in Scheme S2. As is well known, Photocatalysts must be thick enough to absorb incident
light efficiently. Nanofibers have a long axis to absorb incident light, and orthogonally, a short
radial axis to separate charge. However, the photogenerated charge carriers in the nanoparticle
photocatalysts must undergo a relatively longer migration distance, which retard the photocatalytic
reducetion and oxidation reaction. Moreover, the boundaries between different nanoparticles also
act as recombination centers for photogenerated charge carriers, resulting the reduction of
photocatalytic efficiency. Therefore, the high boundary density in nanoparticle photocatalyst has a
negative influence on the photocatalytic water splitting and degradation over RhB.
During the photocatalytic process, hydrogen is produced (Equation 1 and Scheme S2), and the
sulfide and sulfite anions act as sacrificial reagents which is consumed by photogenerated holes
(Equations 2-5 and Scheme S2). Different reactions occur for the photogenerated electrons and
holes as follows:
2H++2eSO32- + 2OH- + 2h+
2S2- + 2h+
S22- + SO32SO32- + S2- + 2h+
H2
1
SO42- + 2H+
2
S22S2O32-+ S2S2O32-
3
4
5
As illustrated in equations 2 and 3, photoinduced holes react with SO32- and S2- to yield SO42- and
S22-, respectively. The production of S22- ions may play as a depressing electron acceptor capturing
the photoexcited electrons, so hinder the water from being reduced. This process can be
suppressed in the presence of SO32- ions by equation 4, and the anions of S2- and S2O32- are
introduced. The ions of S2O32- is colorless that can avoid the decrease of the light absorption
efficiency. More importantly, S2O32- is inactive in the reduction process, which has a little
negative effect on the reaction. Equation 5 represented the main working process of the sacrificial
reagents.
Fig. S1 SEM images of P25 with different magnifications.
Fig. S2 TG analysis of SrTiO3 precursor fibers
In order to display the decomposition process of the precursor fibers, TG analysis was carried out.
As illustrated in Fig. S2, the TG curve elucidates three obvious weight loss processes. The first
mass loss is about 11.9 % before 210 °C, which is resulted from evaporation of acetic acid, methyl
alcohol and a little water. The second obvious weight loss (ca.54.5 %) between 210 and 445 °C is
mainly ascribed to the decomposition of zinc acetate and manganese acetate and PVP. When the
temperature is higher than 450 °C, no discernible weight loss was observed indicating that the
precursor is converted to SrTiO3 nanofibers completely.