Influence of electrolyte composition on the formation of mixed oxide nanotube arrays for solar fuel production

• Published in: Journal of power sources 2015-04, Vol.280, p.339-346
• Main Authors: Deyab, Nourhan M., Steegstra, Patrick, Hubin, Annick, Delplancke, Marie-Paule, Rahier, Hubert, Allam, Nageh K.
• Format: Article
• Language: English
• Subjects: Anodizing; Arrays; Electrolytes; Hydrogen; Mixed oxide; Mixed oxides; Nanostructure; Nanotube; Photoanode; Solar; Sunlight; Titanium dioxide; Ti–Mo–Ni; Water splitting
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2015.01.108

Water splitting using sunlight is an important process for future energy supplies. TiO2 is widely used as photoanode, but has a limited light absorption range. Here, ternary Ti–Mo–Ni mixed oxide nanotube arrays were fabricated via electrochemical anodization of Ti–Mo–Ni alloy in formamide-ethylene glycol-based electrolytes, to extend the absorption range into visible light. The electrolyte composition and anodization time were found crucial in controlling the structural features of the nanotubes. By tuning these parameters, arrays of thin walled (∼9 nm) and ∼8 μm long nanotubes were obtained. In photoelectrochemical water splitting, the mixed oxides showed incident photon conversion efficiency (IPCE) up to 65% for wavelengths from 300 nm to 450 nm. This enhancement in the IPCE of the mixed oxide nanotubes, compared with pure titania, can be related to synergistic effects of Mo and Ni oxides as well as to the unique structural properties of the fabricated mixed oxide nanotubes. [Display omitted] •TiO2 nanotubes containing Ni and Mo were successfully produced form Ti–Ni–Mo alloy.•The electrolyte composition determined the structural features of the resulted nanotubes.•The Ti–Mo–Ni mixed oxide nanotubes exhibited visible light activity.•The Ti–Mo–Ni oxide nanotubes exhibited higher IPCE values than their pure TiO2 counterparts.