Hydrogen production from sodium borohydride originated compounds: Fabrication of electrospun nano-crystalline Co3O4 catalyst and its activity

Abstract

Electrospun nanofibers are prepared through electrospinning followed by post-treatment and preferred to use in catalytic applications. The electrospinning provides advantages for active catalysts design based on activity profiles and features of catalyst. In the present study, we fabricated nano-crystalline cobalt oxide (Co3O4) catalyst by electrospinning technique followed by thermal conditioning. Polyacrylonitrile (PAN) based Co as-spun mats (Co/NMs) with homogeneous diameter were prepared by electrospinnig process under several conditions as applied voltage (15-25 kV), working distance (5-7.5 cm) with the feed rate of 1 ml min(-1). The calcination process as a post-treatment was applied at different temperatures (232 degrees C, 289 degrees C and 450 degrees C) to obtain electrospun nano-crystalline Co3O4 catalyst. Co/NMs catalysts were characterized by XRD, SEM, TEM, XPS, FT-IR, TG/DTG, and ICP-MS techniques. The parametrically study was performed for evaluating the hydrogen production activity of catalyst from sodium borohydride (NaBH4, SBH) and its originated compounds as ammonia borane (NH3BH3, AB) and methyl-amine borane (CH3NH2BH3, MeAB). The relation between the internal-external properties and catalytic activities of catalysts for hydrogen production was investigated. The beadless Co/NMs-1 catalyst with homogeneous diameter was obtained under electrospinnig process conditions at 15 kV applied voltage and 7.5 cm working distance. All catalysts showed activity for hydrogen production, also the significant effect of post treatment process was observed on the catalytic activity as given order: Co/NMs-1(450) > Co/NMs-1(289) > Co/NMs-1 > Co/NMs-1(232). Furthermore, mesoporous Co3O4 cubic crystals (26 nm) in fibrous architecture was prepared by 450 C-post-treatment. Hydrogen production rates were recorded at 60 degrees C as 2.08, 2.20, and 6.39 1 H-2 center dot g(cat)(-1)min(-1) for NaBH4, CH3NH2BH3, and NH3BH3, respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.