Enhanced photocatalytic activity of TiO₂ nanotubes decorated with erbium and reduced graphene oxide

Highly ordered TiO₂ nanotubes (TNTs) decorated with erbium and reduced graphene oxide (rGO) were prepared through anodization, electrochemical deposition, and/or drop-casting. The characteristics of the as-prepared photocatalysts were identified, and the photoelectrochemical and photocatalytic properties were investigated through water splitting and organic degradation. All samples (pure TNTs, Er-TNTs, rGO-TNTs, and rGO-Er-TNTs) were prepared in the anatase phase without any changes in the crystalline phase or impurities. The ternary rGO-Er-TNT photocatalyst exhibited the best performance, with an increased hydrogen evolution rate of 115.37 μmol cm^-2h⁻¹, methylene blue degradation of 91.58%, and photoconversion efficiency of 2.3% (0 V vs. reversible hydrogen electrode). The increased photocatalytic efficiency can be attributed to the combination of enhanced optoelectronic properties and the path for the separation of charge carriers by erbium and rGO. In this study, high-potential solar-active photocatalysts were achieved through the synergistic effect owing to the combination of Er and rGO with TiO₂ nanotubes.