Enhancing the Photoelectrochemical Performance of TiO2 through Decorating a Topological Insulator Bi2Te3 Film and Non-Noble Plasmonic Cu Nanoparticles

Recently, the development of efficient and non-noble photoelectrocatalysts with enhanced light absorption and high photoelectrochemical (PEC) performance has attracted increasing attention due to their potential in addressing the global fossil energy and environment crisis. In this work, we designed and prepared a topological insulator Bi2Te3 film and non-noble plasmonic Cu nanoparticles onto one-dimensional (1D) TiO2 nanorod (NR) array, forming TiO2/Bi2Te3/Cu photoanode. Benefiting from the synergistic effect of plasmonic Cu-induced hot electrons and Bi2Te3-supplied topological high-mobility electron channels, the PEC performance and charge separation of TiO2 were enhanced. Accompanied by the improved light absorption, the optical band gap was narrowed from 3.02 eV for TiO2 to 2.47 eV for TiO2/Bi2Te3/Cu. Moreover, the photocurrent density of pure TiO2 was increased by about 3.05 times, from 0.77 mA/cm2 at 1.23 V vs reversible hydrogen electrode (RHE) for TiO2 to 2.33 mA/cm2 for TiO2/Bi2Te3/Cu. Moreover, the recombination of photogenerated electron–hole pairs was also suppressed, and the carrier lifetime was prolonged from 24.6 ns for bare TiO2 to 33.4 ns for TiO2/Bi2Te3/Cu. As a result, the TiO2/Bi2Te3/Cu photoanode showed good long-term cycling stability, with the H2 generation rate from PEC water splitting reaching 20.3 μmol/cm2/h. Our results suggest that co-decorating topological insulators and plasmonic materials could be a promising strategy to improve the PEC performance of TiO2 and may be applied in other photoelectrocatalysts.