Secondary growth of hierarchical nanostructures composed only of Nb 3 O 7 F single-crystalline nanorods as a new photocatalyst for hydrogen production

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2015, Vol.3 (28), p.14686-14695
• Main Authors: Duan, Junyuan, Mou, Guangying, Zhang, Shuai, Wang, Sheng, Guan, Jianguo
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/C5TA02774H

Development of efficient photocatalysts for hydrogen (H 2 ) production from water splitting is highly sought for the current sustainable energy issue. This paper has demonstrated a one-pot hydrothermal approach for the preparation of hierarchical nanostructures (HNs) composed only of Nb 3 O 7 F single-crystalline nanorods by using H 2 NbF 7 as a precursor and 2-propanol as a selective adsorption agent. In our protocol, modulating the hydrolysis rate of the coordination complex H 2 NbF 7 via simply controlling its concentration not only produces Nb 3 O 7 F single crystalline nanorods by the restrictive growth on [110] due to the selective adsorption of 2-propanol on the sidewalls, but also leads to secondary nucleation for the growth of new nanorods on the pre-formed ones, leading to the formation of Nb 3 O 7 F HNs. The resultant Nb 3 O 7 F HNs strongly respond to ultraviolet light and have a band gap of 3.22 eV as well as the conducting band minimum at −0.44 eV. They exhibit excellent photocatalytic H 2 production activity with a good recycling stability when 0.5 wt% Pt is used as a cocatalyst. The H 2 production rate reaches 830 µmol h −1 g −1 , about 23.7 and 5.7 times higher than that of Nb 2 O 5 sphere-shaped micro-particles and commercial Nb 2 O 5 nanoparticles, respectively. Furthermore, they can also show notable photocatalytic H 2 production activity even without any cocatalysts. This suggests that the resultant Nb 3 O 7 F HNs are promising as a new photocatalyst for H 2 production.