Preparation of the flexible (carbon paper)-based electrodes is shown in Scheme 1a. Laminated carbon paper-based electrodes were prepared accordingly to procedure 2.3 in Experimental Section. During lamination, melted foil has sealed pores in the carbon paper. Therefore, gold had no direct contact with the solutions, but provided an excellent electrical connection to carbon paper. This way, a flexible hand-made carbon electrodes (Scheme 1b) were fabricated.