Citrate-driven modification of gold on titanium wire electrodes by the treatment in aqueous solutions of HAuCl4

The modification of titanium (Ti) wire with gold was explored using a simple treatment of Ti wire in aqueous solutions of HAuCl4. Just immersing Ti wire in the solutions of HAuCl4 could not modify Au on Ti, which was confirmed by observing cyclic voltammograms (CVs) of ferrocyanide using the treated Ti wire as a working electrode. However, the addition of trisodium citrate into aqueous solution of HAuCl4 was found to promote the Au modification of Ti wire showing sigmoidal CV responses of ferrocyanide. The modified states of Au on Ti were discussed based on the electrochemical responses. While our trial was initiated seeking possibilities of easier preparations, the pre-etching of Ti wire with HCl was clarified to be effective to promote the modification of Au on Ti. Consequently, we could observe the electrocatalytic properties for the oxidations of uric acid, ethanol and glucose depending on the degrees of Au modification of Ti. Because unmodified Ti wire electrodes were electrochemically silent for these species, the simple treatments of Ti wire in aqueous solutions containing both HAuCl4 and trisodium citrate were clarified to be effective for the preparation of Au nano-elecctrode ensembles and Au-like electrodes on Ti wire bases. [Display omitted] •Ti wire could be modified with Au by treating with HAuCl4 and trisodium citrate.•Thus-prepared Au modified Ti wire electrodes showed sigmoidal CV responses.•The pre-etching of Ti wire with HCl tuned the electrocatalytic ability of Au on Ti.