1 research outputs found
Enhanced Light Trapping in GaAs/TiO<sub>2</sub>āBased Photocathodes for Hydrogen Production
Photoelectrochemical cells (PEC) are appealing devices
for the
production of renewable energy carriers. In this context, IIIāV
semiconductors such as GaAs are very promising materials due to their
tunable band gaps, which can be appropriately adjusted for sunlight
harvesting. Because of the high cost of these semiconductors, the
nanostructuring of the photoactive layer can help to improve the device
efficiency as well as drastically reduce the amount of material needed.
IIIāV nanowire-based photoelectrodes benefit from the intrinsically
high aspect ratio of nanowires, their enhanced ability to trap light,
and their improved charge separation and collection abilities and
thus are particularly attractive for PECs. However, IIIāV semiconductors
often suffer from corrosion in aqueous electrolytes, preventing their
utilization over long periods under relevant working conditions. Here,
photocathodes of GaAs nanowires protected with thin TiO2 shells were prepared and studied under simulated sunlight irradiation
to assess their photoelectrochemical performances in correlation with
their structural degradation, highlighting the advantageous nanowire
geometry compared to its thin-film counterpart. Morphological and
electronic parameters, such as the aspect ratio of the nanowires and
their doping pattern, were found to strongly influence the photocatalytic
performances of the system. This work highlights the advantageous
combination of nanowires featuring a buried radial pān junction
with Co nanoparticles used as a hydrogen evolution catalyst. The nanostructured
photocathodes exhibit significant photocatalytic activities comparable
with previous noble-metal-based systems. This study demonstrates the
potential of a GaAs nanostructured semiconductor and its reliable
use for photodriven hydrogen production