Nanostructured Cu/ZnO Coupled Composites: Toward Tunable Cu Nanoparticle Sizes and Plasmon Absorption

We report a synthesis method that made use of a dual-glycol system, allowing discrete and size-tunable Cu nanoparticles to be deposited onto ZnO nanorods. Successful reduction of Cu was demonstrated by the distinct plasmon absorption, and we report for the first time a clear linear correlation of Cu plasmon peak position shifts with the variation of Cu particle sizes. Stable and discrete Cu nanoparticles were obtained despite deliberately leaving out conventional polymeric protecting agents such as poly(vinylpyrrolidone). The synthesized material exhibited robustness in ethanol steam reforming that occurred at high reaction temperature of up to 600 °C. Analysis of absorption spectra revealed the relative attenuation of ZnO absorption with increasing amount of Cu nanoparticles deposited, confirming clear electronic interaction between the coupled metallic and oxide components.