Electrodeposition of Gold on Fluorine-Doped Tin Oxide: Characterization and Application for Catalytic Oxidation of Nitrite

Sub-micrometer size gold particles were electrodeposited on a transparent fluorine-doped tin oxide (FTO) from acetonitrile solution containing AuCl4 − and tetramethylammonium tetraflouroborate (TMATFB) for detecting NO2 −. A series of two-electron (2e−) and one-electron (1e−) reductions of the AuCl4 −-AuCl2 −-Au redox systems were observed at FTO and a highly stable and homogeneous distribution of Au on FTO (Au/FTO) was obtained by stepping the potential from 0 to −0.55 V (vs. Ag/Ag+). The Au/FTO electrode exhibited sufficiently high catalytic activity toward the oxidation of NO2 − with a detection limit (S/N = 3) and sensitivity of 2.95 μM and 223.4 μA·cm−2·mM−1, respectively, under optimal conditions. It exhibited an interference-free signal for NO2 − detection with excellent recoveries from real samples. KCI Citation Count: 19