Controlled preparation and visible light photocatalytic activities of corn cob-like Au–ZnO nanorods

A facile method to prepare well-shaped nanohybrids of Au–ZnO nanorods (NRs) has been demonstrated, which is through polyvinylpyrrolidone-assisted in situ nucleation and growth of ZnONRs in the colloidal solution of Au nanoparticles (NPs). The obtained Au–ZnONRs shows uniform corn cob-like morphology with AuNPs evenly deposited on the surface of hexagonal ZnONRs and can be dispersed in aqueous solution to achieve photodegradation of organics. Moreover, the loading amount of AuNPs can be tuned to optimize the photocatalytic performance. The nanohybrid of Au–ZnONRs with optimized AuNP loading exhibits superior photocatalytic activity than ZnONRs alone, demonstrating ~90% Rhodamine B degradation within 18 h under the visible light of 420–780 nm, a wavelength range that does not overlap with ZnO absorption. The observed performance improvement is likely due to the coupling effect between ZnONRs and AuNPs, which functionalizes ZnONRs with visible light utilization and enhances charge separation. The strategy presented here not only provides a new approach for the controlled modification of 1D semiconductor nanostructures, but also holds good potential for applications such as degradation of organic pollutants.