Abstract
In recent years, investigating renewable energy resources, especially hydrogen energy production, is increasingly important in both industries and academia due to the shortage of fuel resources and the threatening of global warming. For hydrogen production, photocatalysts play the key role to overcome the troublesome problems. Among utilization of photocatalysts, tantalum oxide is a promising material for the photogeneration of hydrogen from water compared to widely used TiO2. The advantage is due to its conduction band minimum (CBM) is more negative than TiO2, leading to more photogenerated charge carriers to undergo hydrogen evolution reaction (HER). However, the wide band gap of Ta2O5 (>3.8eV) allows only utilizing UV-light, limiting its H2 production efficiency. The present work aims at improving the rate of H2 evolution with extending the absorption region of solar spectrum by integrating Ta2O5 nanotubes with CuO nanoparticles, possessing a relatively small band gap (1.2-1.8 eV). The results clearly show that the H2 production efficiency of the heterostructure of CuO NPs/Ta2O5 NTs increased significantly, in particular with Cu NPs annealed at 300 °C. Due to their tunable band gap, well-grown interface, and fine particle size, the hydrogen production rates of CuO NPs/Ta2O5 NTs annealed at 300 °C are 70% more than pure NTs. The results indicate that Ta2O5 NTs attached with CuO NPs are promising photocatalytic materials for hydrogen production.