solar driven water evaporation have rarely been reported mainly because of the serious morphological destruction and phase change of MoO3−xnanostructures with increasing the concentration of oxygen vacancies [29, 30]. Here we develop a surface-ligand protected reduction approach for the synthesis of 1D MoO3−xnanobelts with tunable plasmonic absorption in a wide wavelength range by creating controllable oxygen vacancies. By using polyethylene glycol (PEG-400) as both the reductant and surface protected ligands, oxygen vacancies are created in MoO3−xnanobelts to tune plasmonic absorption and the 1D morphology is well maintained simultaneously during the reaction process, enabling the widely tunable plasmonic absorption in 1D MoO3−xnanobelts from 200 to 2,500 nm. Due to the broad plasmonic absorption and 1D structural feature, we further demonstrate the application of the MoO3−xnanobelts as photothermal materials for interfacial solar driven evaporation. The MoO3−xnanobelts are easy to form a thin film on air-laid paper (ALP) by vacuum filtration because of their unique 1D nanostructure. Then, an insulated expandable polyethylene (EPE) foam used as a floatable thermal barrier is wrapped in the MoO3−xnanobelts/ALP on its top to design the interfacial solar evaporator. Benefiting from both the 1D MoO3−xnanobelts with tunable plasmonic absorption and unique design of the interfacial solar evaporator, a high water evaporation rate and durability are realized. This work is believed to promote the synthesis and application of 1D plasmonic semiconductor oxide nanostructures. 2 Experimental2.1 Materials Mo powders (> 99%) were purchased from Shanghai Macklin Bio Chemical Co., Ltd. Hydrogen peroxide (H2O2, 30%) and PEG-400 were purchased from Sinopharm Chemical Reagent Co., Ltd. All the chemicals and reagents used in this study were analytic grade and not further purified. ALP was obtained from Kimberly-Clark Co., USA. EPE foams were obtained from Zibo Baisheng Packing Co., China. 2.2 Synthesis of the MoO3−xnanobelts Typically, 0.6 g of Mo powders were dispersed in a mixture solution of ultrapure water (15 mL), H2O2(30%, 4.0 mL) and different amount of PEG-400. The solution was sealed in autoclaves and then maintained at 180 oC for 12 h. After cooling to room temperature naturally, the samples were obtained by washing with water and ethanol. The samples synthesized in the presence of 0, 100, 200, 500 and 1,000 μL of PEG-400 were named as MoO3, MoO3−x-100, MoO3−x-200, MoO3−x-500 and MoO3−x-1,000, respectively. 2.3 Preparation of the interfacial solar evaporator A suspension of MoO3−xnanobelts was deposited on the porous ALP through vacuum filtration to form a MoO3−xnanobelt film by drying at 25 oC for 24 h. The areal density of the film was about 40 g·m–2. Then the EPE foam was wrapped by the MoO3−xnanobelt film to constitute the evaporator.
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- Fall '10
- Dr. Dutton