The bottom electrode was soaked in 1 M NaHCO3 solution for 2 hours. For the 4 cm 2 electrodes, a 4.84 cm 2 filter paper was wetted with the electrolyte and used as a separator. A 4 cm 2 carbon cloth (AvCarb 1071 HCB) was used to cover the top electrode and served as a gas diffusion layer. The electrodes, separator, and gas diffusion layer were surrounded by an EPDM rubber gasket (9.5 cm × 9.5 cm outer area, 8 cm × 8 cm inside area, 0.15 cm thickness, Fuel cell store) and sandwiched between titanium 7 plates (13 cm × 13 cm, 0.95 cm thick), which served as current collectors. The resulting assembly was pressed together by evenly tightening 16 set screws connecting the Ti plates using a torque wrench to 20 in.lb of force. For 49 cm 2 electrodes, 49 cm 2 carbon cloth and 56 cm 2 filter paper was used while the dimensions of gasket and current collector stayed the same.