posted on 2021-09-10, 16:43authored byAleksandra Lindberg, Oscar Diaz-Morales, Susanne Holmin, Ann Cornell
Identifying the sources
of oxygen in the chlorate process is challenging
due to the complex set of chemical and electrochemical reactions involved.
Here, two types of electrodes have been investigatedTi0.7Ru0.3Ox, and electrodes
with aimed composition Ti0.34Ru0.3Sn0.3Sb0.06Ox, both compared with
platinum anodes. The cell oxygen off-gas was analyzed employing mass
spectrometry together with ex situ UV–vis spectroscopy to quantify
the kinetic rate constants. Noteworthy is that the respective rates
of oxygen formation from anodic and chemical reactions in the presence
of hypochlorite are of the same magnitude. The addition of Sn and
Sb doubled the surface area of the electrodes and decreased oxygen
production when electrodes were used for the first time. However,
rate constants for total oxygen production with reused electrodes
follow the trend: homogeneous hypochlorite decomposition < TiRu
< TiRuSnSb to the highest value obtained by Pt. The same trend
is noticed for rate constants concerning the hypochlorite decomposition.