2 mm thick
GC (Alfa Aesar, Type1) electrodes were polished prior
to use for 1 min each with Buehler Micropolish II deagglomerated alumina
in decreasing particle size from 1.0 to 0.3 to 0.05 μm. In between,
the electrodes were sonicated for 15 min each in 18 MΩ water
(MQ water) and isopropanol (VWR Chemicals).
Electrochemical
treatment of GC was performed by sweeping the potential in a 0.5 M
H2SO4 solution between +1500 and −1000
mV vs Ag/AgCl (3 M KCl) at a scan rate of 50 mV s–1 for 30 cycles.
To prepare Cr-/Au-coated glass electrodes for
spectroscopy, glass
slides were cut into the size of 0.7 × 6.0 cm and subsequently
cleaned via sonication in the following solvents
for 15 min each: acetone (VWR Chemicals), 2% Hellmanex solution (Hellma-Analytics),
MQ water, and isopropanol. Afterward, the samples were treated for
5 min at 50 W in the oxygen plasma oven Plasma ETCH P25. In a thermal
metal evaporation chamber, 5 nm chromium followed by 80 nm of gold
was deposited at ∼10–6 mbar.
Toray
CP (Alfa Aesar, TGP-H 60) was used as received and cut into
an appropriate size of 1.0 × 3.0 cm.
GC (Alfa Aesar, Type1) electrodes were polished prior
to use for 1 min each with Buehler Micropolish II deagglomerated alumina
in decreasing particle size from 1.0 to 0.3 to 0.05 μm. In between,
the electrodes were sonicated for 15 min each in 18 MΩ water
(MQ water) and isopropanol (VWR Chemicals).
Electrochemical
treatment of GC was performed by sweeping the potential in a 0.5 M
H2SO4 solution between +1500 and −1000
mV vs Ag/AgCl (3 M KCl) at a scan rate of 50 mV s–1 for 30 cycles.
To prepare Cr-/Au-coated glass electrodes for
spectroscopy, glass
slides were cut into the size of 0.7 × 6.0 cm and subsequently
cleaned via sonication in the following solvents
for 15 min each: acetone (VWR Chemicals), 2% Hellmanex solution (Hellma-Analytics),
MQ water, and isopropanol. Afterward, the samples were treated for
5 min at 50 W in the oxygen plasma oven Plasma ETCH P25. In a thermal
metal evaporation chamber, 5 nm chromium followed by 80 nm of gold
was deposited at ∼10–6 mbar.
Toray
CP (Alfa Aesar, TGP-H 60) was used as received and cut into
an appropriate size of 1.0 × 3.0 cm.