A comparative study of CuO deposition methods on titania nanotube arrays for photoelectrocatalytic ammonia degradation and hydrogen production

In this study, the deposition of CuO nanoparticles into titania nanotube arrays (TiNTAs) was prepared via two methods, i.e an in-situ anodization (AND) and a successive ionic layer adsorption reaction (SILAR). The two methods were compared in terms of their properties as efficient photoanodes in photoelectrocatalytic processes. FESEM and TEM imaging showed that the nanotubular structure was successfully generated. The bandgap energy was probed by UV-DRS analysis, revealing that CuO-TiNTAs SILAR had a lower bandgap than other samples. The photoelectrochemical responses of CuO-TiNTAs SILAR exhibit better activity compared to its counterpart. The maximum ammonia removal was achieved at 50.1% while as high as 235.7 μmol of hydrogen was generated over 120 min under Hg lamp illumination, by the use of CuO-TiNTAs SILAR. We thereby conclude that, for the given experimental conditions, CuO-TiNTAs SILAR is a better photoanode than CuO-TiNTAs AND concurrently eliminate ammonia and produce hydrogen in a photoelectrochemical setup.