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Photoluminescence Excitation Engineering of Gold Nanoparticle-Decorated Zinc Oxide Nanoflowers for Efficient Visible Photocatalytic Water Treatment

Year: 2026

Type: article

Abstract: Plasmonic metal-semiconductor heterostructures represent an effective strategy for enhancing visible-light-driven photocatalysis and suppressing charge recombination in wide-bandgap oxides. Here, we report the synthesis of hierarchical Au nanoparticle-decorated ZnO nanoflowers (Au/ZnO NFs) and systematically investigate their plasmon-assisted photocatalytic mechanisms. Structural and compositional analyses confirm that Au nanoparticles are uniformly distributed on the ZnO NF surface without disrupting the wurtzite crystal structure. UV-Vis diffuse reflectance spectroscopy demonstrates enhanced visible-light absorption induced by the localized surface plasmon resonance of Au nanoparticles, while the intrinsic band gap of ZnO remains unchanged. Photophysical investigations using steady-state photoluminescence (PL), PL excitation, and time-resolved PL demonstrate that Au decoration significantly suppresses both near-band-edge and defect-related recombination. This suppression arises from plasmon-induced hot-electron generation, efficient interfacial electron transfer, and electron trapping at the Au-ZnO interface, resulting in prolonged carrier lifetimes and enhanced charge separation. These effects promote the generation of reactive oxygen species under visible-light irradiation. Consequently, the Au/ZnO NFs exhibit enhanced visible-light-driven photocatalytic degradation of methylene blue, achieving nearly complete dye removal within a short irradiation time of 30 min. This study proposes a mechanistic understanding of plasmon-enhanced charge-transfer processes in Au/ZnO heterostructures and establishes a promising strategy for designing efficient visible-light-driven photocatalysts for catalytic wastewater treatment.

Source: ACS Omega

DOI: 10.1021/acsomega.6c03907