Nickel-coated 3D-printed titanium electrodes for electrochemical flow reactors

ABSTRACT Electrocatalyst-coated metallic electrodes for electrochemical flow reactors have many applications in electrosynthesis, environmental remediation and energy conversion. This work presents novel nickel-coated titanium-alloy electrodes produced by means of direct metal laser sintering and constant current electrodeposition in an additive-free Wood’s nickel strike then a Watts nickel bath. Several 3D porous architectures were created in Ti-6Al-4 V alloy and coated, their digital design being the subject of previous work. Nickel coatings were macroscopically uniform and adherent with a thickness up to 5.8 µm, depending on the surface area of the electrodes. The morphology of nickel was cauliflower-like, with crystallisation growth occurring as spherical grains, as typically found for deposits from pH buffered Watts baths. Some degree of coating porosity was observed at electrodes of large surface area, indicating the need for longer deposition times. The results open the path for further optimisation of electrodeposition parameters and the development of bath additives to tailor deposit properties.