Light-harvesting Ni/TiO2 nanotubes as photo-electrocatalyst for alcohol oxidation in alkaline media

Anodic photo-electrocatalysts comprising anodically grown TiO2 nanotubes (TiO2-NT) with an average inner diameter of 70 nm and lengths of 7, 15 and 30 μm with nanoparticulate electrodeposited Ni species (namely NiO, Ni(OH)2) were synthesized and evaluated for its use as anode for direct methanol fuel cell. The Ni deposit with an average diameter of 200 nm was obtained by cyclic voltammetry from a modified acid Watts bath. Morphology, composition, crystallinity and optical properties were investigated by SEM, EDS, XRD, Raman and diffuse reflectance spectroscopy. UV-vis irradiation coming from a Xe lamp on the anodes increased the current density by 24% in half-cell configuration. Finally, a microfluidic fuel cell was assembled and tested using methanol as fuel reached an OCP of 0.7 V. This finding suggests that such composite materials are promising alternatives for the development of a new generation of hybrid-microfluidic devices.