Heterojunction characteristics and photoelectrochemical performance of TiO2 nanorods sensitized by zeolitic imidazolate framework

Abstract

Traditional photocatalysts suffer from inferior utilization of solar light. Therefore, developing novel photocatalyst for better solar light harvesting is much required in the wake of current environmental problems arising from conventional energy technologies. Here we report synthesis and characterization of photocatalysts based on TiO2 nanorods (TNR) and Zeolitic Imidazolate Framework-9 (ZIF-9) and their photoelectrochemical properties. The TNRs were sensitized by ZIF-9 through solvothermal method. The presence of ZIF-9 on TNR formed a p-n heterojunction which assisted in initiating efficient charge separation and promoting injection of these carriers into the electrolyte. The heterojunction catalysts also exhibited enhanced optical properties in terms of extended absorption with reduced bandgap in comparison to the TNR film. The aforementioned properties manifested in improved photoelectrochemical performance with a current density of 0.94 mA/cm2, which is four times better than TNR and an applied bias photon to current efficiency (ABPE) of 0.27 %, which is five times better than TNR film alone. These superior properties of the processed ZIF-TNR demonstrate their potential for photoelectrochemical catalysis, thus paving the way for green hydrogen generation.