A novel and chemical stable Co–B nanoflakes-like structure supported over titanium dioxide nanofibers used as catalyst for hydrogen generation from ammonia borane complex. (5th January 2016) - Yousef, Ayman
Abstract: Co–B nanoflakes-like structure supported over nanoporous TiO2 nanofibers (Co–B NFls-TiO2 NFs, nanocatalyst) was synthesized in two steps using electrospinning technique and chemical reduction method. Nanoporous TiO2 NFs were prepared by calcination of electrospun sol–gel consisting of titanium tetraisopropoxide (TIIP) and polyvinylpyrrolidone (PVP). Then, Co–B NFls were supported over TiO2 NFs by chemical reduction of cobalt acetate tetrahydrate (CoAc) over TiO2 NFs using sodium borohydride (NaBH4 ) as a reducing agent. The nanocatalyst was used for hydrogen generation from environmentally safe and non-toxic ammonia borane (AB). TEM and FESEM results revealed that NFls were well supported on the surface of nanoporous TiO2 NFs. The supported NFs helped in precluding Co–B agglomeration, however; the unsupported NFs suffered from agglomeration due to harsh reaction created during hydrogen generation. As the synthesized nanocatalyst showed superior catalytic activity in AB hydrolysis compared to that of Co–B powder. The hydrogen evolution was approximately 2.85 mol in 8 min and 0.7 mol in 22 min using nanocatalyst and Co–B powder, respectively. Furthermore, the synthesized nanocatalyst showed low effective activation energy, Ea ∼16.54 kJ/mol and high maximum rate ∼2745.6 ml g −1 min −1 . Finally, the main features of the prepared nanocatalyst were highly efficient, economical, and recyclable. Graphical abstract: Highlights: Nanocatalyst were synthesized by simple and effective methods. High amount of hydrogen was released by catalytic nanocatalyst at room temperature. The introduced nanocatalyst showed good chemical stability for six cycles. The prepared nanocatalyst revealed low activation energy.