1. Speration of pH – in the absence of convection/mixing H+/OH- transport is diffusion controlled. pH gradient during electrolysis seems to be the obvious effect of limited diffusion speed. Could be it is not – but it should be calculated to check.

2. Presence of the pH gradient implies they have concentration cell. Same problem as above – before explaining potential difference by “charge separation” they should prove observed results are not effects of concentration differences.

Extraordinary claims are there, but evidence has been left behind.

Charge carrying structures doesn’t freak you out? As a rule of thumb, like charges like to get as far away from each other as possible. So they wouldn’t be taking a pony-express ride on the water structure highway they would likely be on the sides of the beaker.

The controls are not as stringent as you may imagine. The capture of CO2 into the solution is a ubiquitous problem in good electrochemistry measurements. Thus as the CO2 dissociates in water to H+ + HCO3- you now have an electrolyte. As the authors didn’t mention taking this precaution, the whole control is suspect.

C&C offered a conventional explanation which does not seem to take account of the controls (no salt, no indicator) performed by O&P. I find the reply by the original authors presents quite a good argument.