2 research outputs found
Dynamic Light Scattering and X‑ray Photoelectron Spectroscopy Characterization of PEGylated Polymer Nanocarriers: Internal Structure and Surface Properties
In this work, nanospheres and nanocapsules
are precipitated in
confined impinging jet mixers through solvent displacement and characterized.
Acetone and water are used as the solvent and antisolvent, respectively,
together with polymethoxypolyethylene glycol cyanoacrylate-<i>co</i>-hexadecylcyanoacrylate and Miglyol as the copolymer and
oil, respectively. Characterization is performed with dynamic light
scattering, with electrophoretic measurements, and for the first time
with X-ray photoelectron spectroscopy. Results show that the presence
of polyethylene glycol chains seems to be more pronounced on the surface
of nanospheres than on that of nanocapsules. The thickness of the
copolymer layer in nanocapsules ranges from 1 to 10 nm, depending
on the value of the oil:copolymer mass ratio. Fast dilution is confirmed
to have a positive effect in suppressing aggregation but can induce
further copolymer precipitation
Optimization of 1D ZnO@TiO<sub>2</sub> Core–Shell Nanostructures for Enhanced Photoelectrochemical Water Splitting under Solar Light Illumination
A fast
and low-cost sol–gel synthesis used to deposit a shell of TiO<sub>2</sub> anatase onto an array of vertically aligned ZnO nanowires
(NWs) is reported in this paper. The influence of the annealing atmosphere
(air or N<sub>2</sub>) and of the NWs preannealing process, before
TiO<sub>2</sub> deposition, on both the physicochemical characteristics
and photoelectrochemical (PEC) performance of the resulting heterostructure,
was studied. The efficient application of the ZnO@TiO<sub>2</sub> core–shells
for the PEC water-splitting reaction, under simulated solar light
illumination (AM 1.5G) solar light illumination
in basic media, is here reported for the first time. This application
has had a dual function: to enhance the photoactivity of pristine
ZnO NWs and to increase the photodegradation stability, because of
the protective role of the TiO<sub>2</sub> shell. It was found that
an air treatment induces a better charge separation and a lower carrier
recombination, which in turn are responsible for an improvement in
the PEC performance with respect to N<sub>2</sub>-treated core–shell
materials. Finally, a photocurrent of 0.40 mA/cm<sup>2</sup> at 1.23
V versus RHE (2.2 times with respect to the pristine ZnO NWs) was
obtained. This achievement can be regarded as a valuable result, considering
similar nanostructured electrodes reported in the literature for this
application