Hydrogen generation as a clean energy through hydrolysis of sodium borohydride over Cu-Fe-B nano powders: Effect of polymers and surfactants

The aim of this study is to prepare Cu-Fe-B catalysts with different Cu:Fe molar ratios under ultrasonic conditions. The catalytic activity of all catalysts is tested for hydrogen generation through hydrolysis of alkaline sodium borohydride solution. The effect of polymers (PEG and PVP) and surfactants (CTAB, SDS and Triton X-100) as stabilizer agents on size, morphology and catalytic activity was studied. XRD, TEM, FE-SEM, ICP-OES and BET techniques have been employed for the characterization of catalysts. The TEM image depicts that PEG-stabilized Cu:Fe (3:1) catalyst is a flaky shaped particle containing many nanosheets. The various morphologies of Cu-Fe-B nano catalysts were also confirmed by FE-SEM images. It can be found that PEG and PVP resulted in puffy and nanoparticle shapes, respectively. FE-SEM images of surfactants stabilized Cu-Fe-B powders, CTAB, SDS and Triton X-100, show platy form and agglomerated particles. The PEG-stabilized Cu-Fe-B catalyst with a Cu: Fe molar ratio of 3:1 shows the best catalytic activity at 318 K. In addition, the effects of the concentration of NaBH4, NaOH and the reaction temperature on catalytic activity of Cu-Fe-B have been studied for the hydrogen generation rate. The results of the kinetic study show that the catalytic hydrolysis of NaBH4 is first order with respect to the catalyst dosage and is also first order with respect to the NaBH4 concentration. The activation energy of the hydrolysis for PEG-stabilized Cu-Fe (3:1) catalysts is calculated as 57 kJ morl. The results of reusability tests show that PEG-stabilized Cu-Fe (3:1) catalyst is active even up to the third run. (C) 2017 Elsevier Ltd. All rights reserved.