Abstracts Book - IMRC 2018

• SWMC-O030
SPUTTERED BISMUTH BASED OXIDES FOR
PHOTOELECTROCHEMICAL WATER SPLITTING
Daynahi Franco 1 , Sandra Elizabeth Rodil 1
1 Universidad Nacional Autónoma de México, Instituto de Investigaciones en Materiales,
Mexico.
Photoelectrochemical (PEC) water splitting is a process that directly produces
hydrogen from water and sunlight using semiconductor materials. The
hydrogen that is produced can be easily transported, stored, and utilized as a
fuel, therefore it is a process that mimicks the natural energy production of the
photosynthesis. Despite many efforts, the ideal efficiency has not been reached
yet, being the identification of suitable semiconductors to use in the
construction of photoelectrodes the biggest challenge. Water electrolysis could
be produced using photovoltaic, however, PEC water splitting integrates both
light absorption and electrochemistry functionalities in the semiconductor,
making it a cheaper and simpler approach. The PEC water splitting process
utilizes semiconductor photoelectrodes to absorb sunlight and generate photoexcited
charge carriers (electrons and holes), which drive the water-splitting
(oxidation or reduction) reactions on its surface. However, the energetic
requirements for a single semiconductor to induce both reactions are rarely
fulfilled, so a feasible option is to tandem systems which uses a paired
photoelectrode system (photoanode combined with photocathode). Among the
possible materials used as photoelectrodes, metal oxides offer stability and a
bandgap energies in the visible range of 1.5–2.3 eV. Two promising ternary metal
oxides that have been identified as photoanode and photocathode, respectively
are Bi2CuO4 and BiVO4. This talk will exemplify our on-going interest and great
effort in developing the synthesis of both materials using magnetron sputtering,
as a large scale synthesis method for planar electrodes. The films were
deposited on transparent conductive oxides using a co-sputtering method
comprising Bi2O3 and metallic (V or Cu) targets. The results indicate that the
monoclinic BiVO4 phase, which is the attractive phase for PEC, is easily obtained
after annealing the films in air at 400 °C. However, the photocathode material,
Bi2CuO4, was more complicated, since CuOx segregated phases where formed
under the different deposition conditions.