A self-assembled urchin-like TiO2@Ag–CuO with enhanced photocatalytic activity toward tetracycline hydrochloride degradation

Hetero-junctions are widely considered as efficient and promising separators for photogenerated electron–hole pairs in photocatalytic processes. In this work, a self-assembled urchin-like TiO2@Ag–CuO hetero-junction was fabricated via a two-step approach combining a dealloying method with calcination using alloy ribbons as the precursors. This nanostructure exhibits enhanced degradation efficiency toward tetracycline hydrochloride (TC) under visible light irradiation, achieving a degradability of 82.86% after 3 hours, higher than those of P25, CuO, TiO2@Ag and TiO2@CuO binary hetero-junctions. The photocurrent response and electrochemical impedance spectroscopy studies reveal that the TiO2@Ag–CuO hetero-junction possesses an excellent separation ability and a long lifespan with regard to photogenerated electron–hole pairs, which may contribute to its enhanced photocatalytic ability. In addition, this unique nanostucture maintained good degradation stability even after four-cycle utilization. The findings of this work provide new ideas to prepare multicomponent hetero-junctions for water purification.