Figure 1: Experimental setup, electron micrograph and cyclic voltammogram of nanoporous gold.

(a) Schematics of the experimental setup for imbibition of aqueous electrolytes into nanoporous gold (NPG) under controlled electrode potential. WE, working electrode; RE, reference electrode; CE, counter electrode. (b) Scanning electron micrograph showing the microstructure of NPG. Scale bar, 100 nm. (c) Cyclic voltammogram of current density, j, versus potential, E, in 1 M KOH solution at the potential scan rate of 1 mV s−1. The reference electrode is Ag/AgCl in 3 M KCl.