1

Additional Material for Reviewer

Index

• To confirm that copper oxide forms on the surface in presence of low concentrations of L-Glutamic acid and high concentrations of hydrogen peroxide– Next 5 slides with photos of Cu disc, before and after

immersion in various solutions (slides 2-6)

• To evaluate the adsorption of L-glutamic acid on copper surface in the absence of peroxide– Last slide (Slide No 7)

2

Disc in water

Before After 20 mins

3

Disc in 0.01% glutamic acid

BeforeAfter 20 mins

Solution remains clear

4

Disc in 0.01% glutamic acid & 0.5% H2O2 solution

BeforeAfter 20 mins

After 5 mins, in liquid

Solution remains clear, after 20 mins

5

Disc 0.01% glutamic acid & 10% H2O2 solution

Before

In solution, after 5 mins

After 20 mins

Solution remains clear, after 20 mins

6

Disc in 1% glutamic acid & 10% H2O2 solution

Before

In solution, after 5 mins

After 20 mins

After 15 mins. Note the blue color of solution

After 20 mins.

7

To evaluate L-Glu adsorption

• Impedance equivalent circuit fit parameters

• Non Linear Least Square Fit (fminsearch function in Matlab) gives, best fit K value as 74.37 m3/mol

• This leads to G = -37.7 kJ/mol

Glu Conc (wt%)

Glu Conc (mM) R-s Q-Yo Q-n Rt W

Surface Coverage

0 0 8.325 0.001257 0.5946 56.9 0.03809 0

0.05 3.38 6.178 0.000609 0.6852 202 0.03058 0.718317

0.1 6.76 6.64 0.000521 0.7093 385.4 0.01973 0.852361

0.3 20.28 7.926 0.000472 0.7088 543.3 0.01565 0.89527

0.5 33.8 11.03 0.000205 0.6864 1343 0.00341 0.957632

1 67.6 17.63 0.00018 0.7052 1265 0.003355 0.95502