Effect of the residual silver and adsorbed lead anions towards the electrocatalytic methanol oxidation on nanoporous gold in alkaline media

• Residual Au on nanoporous gold enhances the electrocatalytic activity towards methanol oxidation. Pb UPD can be used to selectively decorate and block surface sites gold. Plumbites and/or adsorbed IV species promoting MOR. Defects or wide single crystal domains are active oxidation at different potential. Nanoporous (NPG) obtained by potentiostatic dealloying of an AuAg master alloy was pulverized, filled into a cavity microelectrode its electrochemistry investigated in NaOH KOH solutions. This method yielded highly resolved undistorted voltammograms this polycrystalline material with clear evidences for segregation Ag during storage air. One cycle 0.1 M H 2 SO 4 remove most residual from as evidenced voltammetry after back transfer alkaline solution X-ray photoelectron spectroscopy (XPS). After removal surface, undergoes rephasing forming wider {111} {110} terraces underpotential deposition (UPD). By adjustment bulk concentration II species, selective partial coverage high internal area NPG could intentionally adjusted. Lead remain attached potentials positive regions either plumbates XPS. Those tools enable disentangle effects electrocatalysis reaction (MOR) potential 1 concentrations KOH. The MOR commences lower presence Ag. At very potential, promotes CO /CO 3 2- . Tafel analysis blocking specific facets shows that promote especially first step while enhance rate further steps rate-limiting higher potentials. While coverages layers plumbate anions inhibit electrooxidation, behavior electrodes low is reminiscent caused methoxide OH - adsorption overpotentials catalyzing complete bound catalytic currents increase base compared NaOH. Comparable parameters lines suggest effect result slightly stronger deprotonation