2 research outputs found
Improving the Stability and Efficiency of CuO Photocathodes for Solar Hydrogen Production through Modification with Iron
Cupric
oxide (CuO) is considered as a promising photocathode material for
photo(electro)chemical water splitting because of its suitable band
gap, low cost related to copper earth abundancy, and straightforward
fabrication. The main challenge for the development of practical CuO-based
photocathodes for solar hydrogen evolution is to enhance its stability
against photocorrosion. In this work, stable and efficient CuO photocathodes
have been developed by using a simple and cost-effective methodology.
CuO films, composed of nanowires and prepared by chemical oxidation
of electrodeposited Cu, develop relatively high photocurrents in 1
M NaOH. However, this photocurrent appears to be partly associated
with photocorrosion of CuO. It is significant though that, even unprotected,
a faradaic efficiency for hydrogen evolution of ∼45% is attained.
The incorporation of iron through an impregnation method, followed
by a high-temperature thermal treatment for promoting the external
phase transition of the nanowires from CuO to ternary copper iron
oxide, was found to provide an improved stability at the expense of
photocurrent, which decreases to about one-third of its initial value.
In contrast, a faradaic efficiency for hydrogen evolution of ∼100%
is achieved even in the absence of co-catalysts, which is ascribable
to the favorable band positions of CuO and the iron copper ternary
oxide in the core–shell structure of the nanowires
Toward Tandem Solar Cells for Water Splitting Using Polymer Electrolytes
Tandem photoelectrochemical cells,
formed by two photoelectrodes
with complementary light absorption, have been proposed to be a viable
approach for obtaining clean hydrogen. This requires the development
of new designs that allow for upscaling, which would be favored by
the use of transparent polymer electrolyte membranes (PEMs) instead
of conventional liquid electrolytes. This article focuses on the photoelectrochemical
performance of a water-splitting tandem cell based on a phosphorus-modified
α-Fe<sub>2</sub>O<sub>3</sub> photoanode and on an iron-modified
CuO photocathode, with the employment of an alkaline PEM. Such a photoelectrochemical
cell works even in the absence of bias, although significant effort
should be directed to the optimization of the photoelectrode/PEM interface.
In addition, the results reveal that the employment of polymer electrolytes
increases the stability of the device, especially in the case of the
photocathode