A one-step solvothermal synthesis of the topological insulator Bi2Te3 nanorod-modified TiO2 photocatalyst for enhanced H2-evolution activity

Abstract

Bismuth sulfide (Bi₂S₃) as a cocatalyst shows a limited photocatalytic H₂ evolution performance due to its low conductivity and strong S–H bond, which is not beneficial to the transmission of photoexcited electrons and hydrogen desorption. Therefore, it is very important to explore new Bi-based cocatalysts with high conductivity and appropriate hydrogen adsorption–desorption ability. In this work, the topological insulator Bi₂Te₃ nanorods worked as an effective cocatalyst to facilitate the photocatalytic H₂-evolution activity of TiO₂ because of its high conductivity and suitable Te–H bond. Bi₂Te₃ nanorod modified-TiO₂ (Bi₂Te₃/TiO₂) has been successfully prepared by a one-step EG-assisted solvothermal method. The H₂-evolution results showed that the Bi₂Te₃/TiO₂(0.5 wt%) sample reached a high photocatalytic hydrogen-generation performance (1494 μmol h⁻¹ g⁻¹, AQE = 7.18%), which is 143.7, 3.0 and 1.2 times those of TiO₂, Bi₂S₃/TiO₂(0.5 wt%), and Bi₂Se₃/TiO₂(0.5 wt%), respectively. The boosted photocatalytic H₂-generation activity can be ascribed to the synergistic effect of topological insulator Bi₂Te₃ as an electron transport medium to rapidly transfer electrons owing to its highly conducting surface states and Te atoms as high-efficiency H₂-generation sites to accelerate the H₂-generation reaction due to appropriate Te–H bond. This paper affords a new insight for exploiting novel Bi-based cocatalysts to further enhance the photocatalytic hydrogen-production efficiency of photocatalysts.