科研之友
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摘要
Photothermocatalysis provides a green approach to convert solar energy to chemical energy. In previous studies, the most catalysts were powdered particles, which faces a problem that the light irradiation cannot reach the underlying catalysts, thereby making these catalysts not exhibit activity. A possible resolution to this difficulty is to load active phase on a thin substrate. In this study, a photothermocatalytic film of Ru/quartz filter paper (abbreviated as QFP) was designed, in which the Ru particles were loaded on a QFP with a thickness as thin as 0.36 mm. A photothermal synthesis was adopted to load the Ru particles. A 5 mu L of precursor of RuCl3 ethanol solution was dripped on the QFP and then the QFP was dried under the irradiation of Xe lamp; this operation was repeated until all the precursor were loaded. After that, the QFP with Ru precursor was reduced in an atmosphere of H-2/Ar mixture [V(H-2):V(Ar)=1:9] at photothermal 400 degrees C for 30 min. The loading mass of Ru particles were optimized by loading 1, 2, 3, and 4 mg of Ru on QFP to fabricate four samples. The X-ray diffraction (XRD) measurement revealed that the QFP was amorphous while the loaded Ru particles were metallic. The scanning electronic microscopy (SEM) indicated that the Ru particles were loaded on the SiO2 fiber of QFP steadily and most of Ru particles possessed a size less than 200 nm. Next, the photothermocatalytic CO2 methanation was carried out over the as-prepared catalysts to assess their catalytic activity. The catalyst with 2 mg Ru loading showed the highest performance; it delivered an 85.5% of CO2 conversion during 2 h of light irradiation. Although the four samples exhibited different CO2 conversion, the selectivities for CH4 product over these samples were all close to 100%. The stability of optimal catalyst was tested in a flow-type reaction system; under a 5 mL.min(-1) flow rate of reactant gases, the CO2 conversion over the catalyst could remain around 51% during 12 h and the apparent CH4 yield rate reached 478.1 mmol.g(Ru)(-1).h(-1). This study demonstrates a photothermal synthesis of recyclable Ru/QFP film and its application of photothermocatalytic CO2 methanation, which provides an energy-efficient process to achieve decarbonization and therefore is of great potential for practical application.
