Unveiling the relationships between (010) facets-orientation growth and photocatalytic activity in W18O49 nanowires

Crystal facets-orientation growth plays a crucial role in determining photocatalytic performance. Herein, a series of (010) facets-oriented W18O49 nanowires were controllably synthesized by a facile solvothermal alcoholysis method using octadecylamine as the crystal growth capping agent in order to regulate the specific growth behavior and unveil its correlation with photocatalytic performance. The properties of the prepared W18O49 nanowires, such as surface oxygen vacancies, light absorption and the band gap size, as well as the surface charge carriers separation rate, could be well-modulated via tailoring the preferred orientation growth. The W18O49 nanowire with the strongest (010)-faceted orientation demonstrated the best photocatalytic degradation of Methyl Orange under ultraviolet light irradiation (up to 100% within 15 min) and visible light irradiation (up to 91% within 95 min). These interesting findings not only help us to gain an in-depth understanding of the relationship between the preferred orientation growth and the photocatalytic performance but also have the potential to open up an innovative route/protocols for the preparation of crystal facets-oriented metal oxides for highly efficient photocatalysis. •Octadecylamine can regulate the orientation growth behavior of W18O49.•Unveiling the relationship between orientation growth and photocatalytic activity.•The mechanism of the high catalytic activity of W18O49 has been clearly explored.