Lab-scale flow photoreactor implementation for direct CO 2 and H 2 O conversion into solar fuels Mikel Tellechea, Zoubir El Hachemi LEITAT Technological Center, Carrer Innovació 2, 08225 Terrassa, Barcelona, Spain This study is framed within the Nefertiti project, which aims to develop an innovative and highly efficient photocatalytic system to simultaneous conversion of CO 2 and H 2 O into C 2+ alcohols. The system is predicated on the utilization of two consecutive photocatalytic flow reactors each anchored with a functional catalyst specific to its respective reaction. Each reaction will be implemented separately at the lab-scale. The results obtained from these experiments will be used to develop a scaled-up system under real sunlight. To implement this process on lab-scale, a closed housing was built to ensure safe operation and validation of the optical system. A white LED with a collimation lens was used as source of light to simulate sunlight. For the first transformation from CO 2 and H 2 O to syngas, CO 2 /H 2 O ratio was tested both in gas and liquid phase 1 . For the next reaction a higher H 2 /CO ratio will be required to achieve the desired products. On the other hand, CO 2 reduction to CO was observed to achieve lower conversion. For oxygen removal, commercial adsorbents were tested in-line. Low O 2 concentration is desirable to perform the second transformation. Transition metals placed into a photoactive 2D COF was the designed hybrid system to be tested. This catalyst was anchored onto a functionalized glass reactor. The exterior of the glass reactor was covered with a rhodamine based Luminescent Solar Concentrator (LSC) to improve irradiation on the catalyst active wavelength. For the second transformation, H 2 /CO gas ratio and reaction temperature were key parameters to achieve the desired products. Syngas (CO+H 2 ) is a versatile feedstock for synthesizing various products (e.g., methane, methanol, alkanes, acetone, C 2+ alcohols…). To achieve higher yields of oxygenated molecules like small alcohols or formaldehyde, the reaction should be performed at lower temperatures and high activity catalysts 2 . For this purpose, a novel catalyst supported using CNT as nanocontainer) was designed. As mentioned before, this catalyst was anchored onto a functionalized glass reactor, and an LSC was applied externally. The obtained products were purified through two membrane purification units. The first membrane separated pure water for recycling into the first reaction to optimize the process. The second membrane separated oxygenated products. Specifically, the target C 2+ alcohols. Both systems were connected in-line to a GC-BID. This two column GC system was configurated such that the first column separates compounds from H 2 to CH 4 , while the second one could analyze compounds from CO 2 to small organic molecules. This analytical system was designed to be suitable for characterizing the products from both reactions within the Nefertiti project system. References 1. Ali, S., Flores, M.C., Razzaq, A., Sorcar, S., Hiragond, C.B., Kim, H.R., Park, Y.H., Hwang, Y., Kim, H.S., Kim, H. & Gong, E.H., (2019). Catalysts, 9(9), 727. 2. Grim R G, To A T, Farberow C A, et al. Growing the bioeconomy through catalysis: a review of recent advancements in the production of fuels and chemicals from syngas-derived oxygenates[J]. ACS Catalysis , 2019 , 9(5): 4145-4172.
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