Electroreduction of nitrobenzene on titanium electrode implanted with platinum

The titanium substrates were bombarded with 5×1017 ions cm−2 of platinum. The surface composition of implanted electrode and concentration-depth profiles of various elements were measured by AES. The chemical state of Pt in titanium electrode implanted with platinum (Pt/Ti) was detected by X-ray photoelectron spectroscopy (XPS). The process and mechanism of the electroreduction of nitrobenzene (NB) in 0.1 M NaOH solution at Pt/Ti electrode have been investigated by cyclic voltammetry, rotating ring-disk electrode (RRDE) and Electron Spin Resonance (ESR) in-situ. The results indicated that the electrocatalytic activity of implanted substrates was much more active than that of the untreated ones. Meanwhile, the electrocatalytic activity of Pt/Ti electrode was also higher than that of smooth Pt. The NB anion-radical, which is the product of one-electron reduction of NB, was detected by ESR in-situ in conjunction with electrochemical methods. The results of RRDE also showed that the first stage of the electroreduction of NB in alkaline solution involves formation of an anion-radical that then can be reduced to phenylhydroxylamine successively.