2023

Reza Bilesan Mohammad; Yazdani Meghdad; Luneau Mathilde; Montserrat‐Sisó Gerard; Wickman Björn; Repo Eveliina

AbstractElectrochemical processes use expensive noble metal-based anodes which limit industrial implementation. In this study, a noble-metal-free Ti-6Al-4V anode is introduced in an advanced flow reactor. We demonstrate that the 3D additively manufactured electrode can provide a more projected surface area and facilitate anodic reactions under controlled electrolyte conditions. Alkaline NaOH and KOH electrolytes act as anodic electrolytes that are toxic compounds-free and enable corrosion control. Impedance and voltammetry responses to electrochemical reactions are studied. The electrochemical active surface area of the 4 rods scaffold geometry is 42 times higher than a flat plate anode. Therefore, improved charge transfer is achieved in the flow reactor incorporating the 3D Ti-6Al-4V electrode due to the increased surface area and wettability. The structure of almost non-conductive passivation on a flat plate anode is changed to unstable passivation due to the 3D scaffold structure. This enables effective charge transfer of 911 mA cm-2 at higher potentials up to 5 V for 1.5 m KOH in a non-flow condition. Furthermore, a 1 m KOH solution delays metal ion dissolution from the anode surface by acting as a corrosion-controlling medium. 3D Ti-6Al-4V is likely to be an affordable alternative anode in alkaline environmentally friendly electrochemical applications.