Efficient nano titanium electrode via a two-step electrochemical anodization with reconstructed nanotubes: Electrochemical activity and stability

A two-step anodization method was used to prepare an efficient nano Ti electrode (ENTE), based on the nano Ti electrode (NTE) that was synthesized by the traditional anodization method. The result of FESEM showed there were many nanopores and nanoparticles on the surface of the ENTE. Compared with Ti electrode, the ENTE exhibited an increased electrochemical activity of nitrate reduction, attributing to its similar to 1.09-fold higher reduction peak current density. Values of average current efficiency towards nitrate reduction indicated that the electrochemical properties of different electrodes were raised in the order of ENTE (0.36) > NIT (0.25) > Ti electrode (0.15). The ENTE exhibited a similar to 3.33-fold higher electroactive surface area than that of Ti electrode. The higher current density throughout the 1000 s and the similar to 1.27-fold higher final current density at 1000 s suggested that the ENTE had a higher stability for nitrate electroreduction. The nitrate reduction efficiency increased with the increasing of initial nitrate-nitrogen concentration and temperature. Similar effect was obtained from current density below 50 mA cm(-2). And under the neutral condition, a higher nitrate reduction efficiency was achieved. The curved surface and higher surface area due to the nanopores of the ENTE increased the nitrate concentration in the EDL and enhanced the potential of individual nitrate ions in the diffuse layer exponentially. This research provided a new route to assess a nano-electrode with high stability and a clear reaction mechanism in EDL (C) 2018 Elsevier Ltd. All rights reserved.