Efficient Photocatalytic Hydrogen Production By Ta2O5 Nanotube Powders Sputtered Decorated with Ni Nanoparticles

Modern life requires abundant and economical energy, and the sun is the best source of energy on earth. Research into materials and techniques which enable the transformation of energy from the sun has increased in recent decades due to the environmental problems associated with the use of fossil fuels. In this context, after the pioneering work of Honda and Fujishima using semiconductor photoanodes for water splitting,[1] photocatalytic hydrogen production has emerged as a low-cost alternative process for producing clean and renewable fuels. A number of oxide semiconductor photocatalysts, such as TiO₂, NaTaO₃ and Ta₂O₅, have been studied. They show reasonable photolysis efficiency, especially in Ta-based photocatalysts under UV light irradiation.[2-4] The photocatalytic activity can be drastically improved by loading NiO-Ni nanoparticle (NP) co-catalysts onto the surface of these Ta-based materials. In this respect, loading NiO-Ni NP co-catalysts onto Ta-based oxides has been reported as an important strategy for enhancing the overall activity of photocatalytic water splitting. Here we prepared very small Ni(0) nanoparticles (NPs) supported onto Ta₂O₅ nanotubes by magnetron sputtering deposition method. Ta₂O₅ nanotubes with 0.126 wt% of Ni showed superior photocatalytic activity for hydrogen production by water splitting when compared to pure Ta₂O₅ nanotubes, with a photonic efficiency estimated at 7.41%. In addition, insights into the role of Ni co-catalysts were obtained using in situ X-ray absorption spectroscopy (XAS) experiments performed at the Ta L₃-edge and the Ni K-edge, both with and without simulated solar irradiation.

REFERENCES 

1.            A. Fujishima and K. Honda, Nature, 1972, 238, 37-38.

2.            P. Zhang, J. Zhang and J. Gong, Chem. Soc. Rev., 2014.

3.            Z. Zou, et al, Nature, 2001, 414, 625-627.

4.            R. V. Gonçalves, et al, J. Phys. Chem. C., 2012, 116, 14022-14030.