Exploring the photocatalytic production of hydrogen by Co, Cu or Pd species as co-catalysts supported on a ZnxTiyOz perovskite/TiO2 structure

Abstract

A key factor for improving the performance of the hydrogen photocatalytic reaction is the logical, functional, and effective design of the photogenerated charge transfer through the solid-solid interface in a heterojunction. This point is particularly crucial in cases such as the one of TiO2, where a relatively rapid recombination occurs. In this work, a ZnxTiyOz/TiO2 heterojunction using the sol-gel nucleation is presented. This method gives rise to a strong and efficient interaction between ZnxTiyOz and TiO2, increasing the photocatalytic activity. Moreover, the addition of Co, Cu or Pd species to the heterojunction surface increases the hydrogen production, due to the strong interaction between them as shown by HRTEM and XPS analyses. Furthermore, the (photo)electrochemical characterization shows that the resistance to charge transfer decreases with co-catalysts, observing the following trend: Pd < Cu < Co. This outcome is related to the mobility and separation of charge carriers and the role played by co-catalysts in hydrogen production.