Polymeric ionic liquid forms of PEI microgels as catalysts for hydrogen production via sodium borohydride methanolysis

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Demirci S., Suner S., Yıldız M., Sahiner N.

JOURNAL OF MOLECULAR LIQUIDS, cilt.360, 2022 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 360
  • Basım Tarihi: 2022
  • Doi Numarası: 10.1016/j.molliq.2022.119562
  • Dergi Adı: JOURNAL OF MOLECULAR LIQUIDS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, INSPEC
  • Anahtar Kelimeler: PEI microgel, PIL microgel, PIL catalyst, H-2 release, Green energy, METAL-FREE CATALYST, H-2 PRODUCTION, ENERGY-CONVERSION, CARBON NANOTUBES, GREEN CATALYST, GENERATION, NABH4, HYDROLYSIS, SYSTEMS, WATER
  • Çanakkale Onsekiz Mart Üniversitesi Adresli: Evet

Özet

Ionic liquid (IL) forms of polyethyleneimine (PEI) microgels were prepared using anion exchange and direct acid treatment techniques employing tetrafluoroborate (TFB) and hexafluorophosphate (HFP) anions as well as their corresponding acids, tetrafluoroboric acid (TFBA) and hexafluorophosphoric acid (HFPA), respectively. Then, these polymeric ionic liquids (PIL) of PEI microgels were used as metal-free catalysts for hydrogen (H-2) production from sodium borohydride (NaBH4) solution in methanol (methanolysis). The parameters affecting H-2 production rates such as the types of anions, the methods of PIL preparation, temperature, reusability, and regeneration of PEI-based microgels were investigated. In the dehydrogenation reaction of NaBH4 in methanol catalyzed by PEI-based PIL microgels, the lowest Ea value in the temperature range of-10-40 degrees C was calculated as 16.0 +/- 0.8 kJ/mol for PEI-HFP PIL micro gel, prepared by anion exchange method. The reusability studies of PEI-TFB PIL microgels revealed that the catalytic activity was decreased to 89 +/- 5% after 5 consecutive use with 100% conversions for every use. Additionally, independent of the anion exchange methods, PEI-based PIL microgels afford catalytic H2 production from NaBH4 methanolysis in a wide range of temperatures including subzero temperatures with facile regenerations by the treatments with TFBA and HFPA resulting in 100% recovery of catalytic activities at each regeneration. The metal-free PIL form of PEI microgel catalyst renders much better catalytic performances and advantages than metal nanoparticle-based catalysts for green H2 production offering viable alternatives in industrial application. (C) 2022 Elsevier B.V. All rights reserved.