光热催化提供了一条将太阳能转变为化学能的绿色途径. 既往光热催化剂多数为分散颗粒粉体, 面临底层催化剂无法被光照而不能充分利用的问题. 本研究开发了一种钌(Ru)/石英滤纸光热催化膜, Ru金属颗粒负载于厚度为0.36 mm的石英滤纸上, 使得所负载的Ru金属颗粒均能够充分进行光热转换进而催化CO₂甲烷化反应. 此外, 该钌/石英滤纸采用光热合成方法制备, 极大节约催化剂生产能耗, 该光热催化膜也便于回收再利用, 因而具有潜在应用前景.

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 μL 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 H₂/Ar mixture [V(H₂)∶V(Ar)=1∶9] at photothermal 400 ℃ 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.