ZnO和ZnO/Au纳米流体的制备及光热转换性能

太阳能光热利用是太阳能利用的重要方面,其中,纳米流体光学特性对太阳能光热利用效率起着决定性作用。通过水热法制备不同形貌的ZnO纳米颗粒,再利用硼氢化钠还原法将Au成功还原在ZnO纳米颗粒上,制备出ZnO/Au复合纳米材料。通过SEM、XRD表征ZnO和ZnO/Au纳米粒子的形貌结构与成分。经紫外/可见/近红外吸收光谱测试表明ZnO/Au纳米流体显著提高了在可见光波段的吸收。通过光热转换实验表明,花状ZnO纳米流体的光热转换性能优于棒状ZnO纳米流体, ZnO/Au纳米流体由于Au的等离激元效应,光热转换特性增强。当浓度为1.0 mg/mL时,棒状ZnO/10%Au纳米流体光热转换效率为59%,比纯导热油纳米流体提高16%;当浓度为0.5 mg/mL时,花状ZnO/10%Au纳米流体光热转换效率为71%,比纯导热油纳米流体提高28%。

Preparation and Photothermal Conversion Properties of ZnO and ZnO/Au Nanofluids

Solar photothermal utilization is the important aspect of solar energy utilization, among which the optical characteristics of nanofluids play a decisive role in the efficiency of solar photothermal utilization. ZnO nanoparticles with different morphologies were prepared by hydrothermal method, and then Au was successfully reduced to ZnO nanoparticles by sodium borohydride reduction method to prepare ZnO/Au composite nanomaterials. The morphology, structure and composition of ZnO and ZnO/Au nanoparticles were characterized by SEM and XRD. The UV/VIS/NIR absorption spectra show that ZnO/Au nanofluids significantly improve the absorption in the visible light band. Through the photothermal conversion experiment, the photothermal conversion performance of flower like ZnO nanofluids is better than that of rod like ZnO nanofluids. Due to the plasmon effect of Au, the photothermal conversion performance of ZnO/Au nanofluids is enhanced. When the concentration is 1.0 mg/mL, the photo thermal conversion efficiency of rod like ZnO/10% Au nanofluids is 59%, which is 16% higher than that of pure heat transfer oil nanofluids. When the concentration is 0.5 mg/mL, the photo thermal conversion efficiency of flower like ZnO/10% Au nanofluids is 71%, which is 28% higher than that of pure heat transfer oil nanofluids.