Controlled
Design of Functional Nano-Coatings: Reduction of Loss Mechanisms in
Photoelectrochemical Water Splitting
Steve Landsmann
Yuri Surace
Matthias Trottmann
Stefan Dilger
Anke Weidenkaff
Simone Pokrant
10.1021/acsami.6b01129.s002
https://acs.figshare.com/articles/media/Controlled_Design_of_Functional_Nano_Coatings_Reduction_of_Loss_Mechanisms_in_Photoelectrochemical_Water_Splitting/3363388
Efficient water splitting
with photoelectrodes requires highly performing and stable photoactive
materials. Since there is no material known which fulfills all these
requirements because of various loss mechanisms, we present a strategy
for efficiency enhancement of photoanodes via deposition of functional
coatings in the nanometer range. Origins of performance losses in
particle-based oxynitride photoanodes were identified and specifically
designed coatings were deposited to address each loss mechanism individually.
Amorphous TiO<sub>2</sub> located at interparticle boundaries enables
high electron conductivity. A thin layer of amorphous Ta<sub>2</sub>O<sub>5</sub> can be used as protection layer for photoanodes because
of its hole conductivity and thermal and chemical stability. An amorphous
layer of NiO<sub><i>x</i></sub> and Co(OH)<sub>2</sub> reduces
photocorrosion or increases water oxidation kinetics because they
act as a hole-capture material or water oxidation catalyst, respectively.
Crystalline CoO<sub><i>x</i></sub> nanoparticles increase
photocurrent and reduce the onset potential due to enhanced charge
separation. The combination of all coatings deposited by a scalable,
mild, and reproducible step-by-step approach leads to high-performance
oxynitride-based photoanodes providing a maximum photocurrent of 2.52
mA/cm<sup>2</sup> at 1.23 V<sub>RHE</sub> under AM1.5G illumination.
2016-05-09 15:34:09
protection layer
water oxidation catalyst
chemical stability
Photoelectrochemical Water Splitting Efficient water splitting
loss mechanism
hole conductivity
Ta 2 O 5
photoactive materials
performance losses
1.23 V RHE
Loss Mechanisms
Controlled Design
electron conductivity
nanometer range
charge separation
NiO x
coating
Amorphous TiO 2
AM 1.5G illumination
photoanode
Crystalline CoO x nanoparticles increase photocurrent
interparticle boundaries
loss mechanisms
increases water oxidation kinetics
efficiency enhancement