One-pot synthesis of Cu-modified HNb3O8 nanobelts with enhanced photocatalytic hydrogen production

Abstract

Ultrathin nanomaterials have aroused much attention because of their enhanced photocatalytic activities. However, conventional exfoliation methods require a complex preparation procedure, and the intercalated cationic organic compounds are difficult to remove. Herein, HNb₃O₈ nanobelts were successfully prepared via a one-pot hydrothermal route by using POM precursors. With the aid of acetic acid, Cu ions were easily loaded through a one-pot synthesis, and they significantly enhanced the photocatalytic water splitting performance (8 times higher than that of unmodified nanobelts). Based on the XPS results, we found that the Cu ions had mixed oxidation states of Cu⁺/Cu²⁺, and the ratio did not change after calcination at 350 °C, indicating that some of the Cu⁺ ions were inserted between the layers. The role of Cu in promoting hydrogen evolution activities was attributed to the improvement in the separation of photo-induced carriers and the photo-to-electron conversion efficiency; these observations were confirmed by the analyses of photocurrent response and photoluminescence.