Amorphous Co−B-based catalyst powder, produced by chemical reduction of cobalt salts, was used as the
target material for Co−B thin film catalyst preparation through pulsed laser deposition (PLD). A comparative
kinetic analysis of the sodium borohydride (NaBH4) hydrolysis by using Co−B catalyst added to the hydride
solution as powder or as thin film was carried out. Both forms of catalyst (powder and film) were heat-treated at 623 K for 2 h under various atmospheric conditions (in vacuum or by using Ar, H2, and O2 gases)
in order to study their effects on H2 generation rate. Surface morphology of the catalyst was studied using
scanning electron microscopy (SEM) and atomic force microscopy (AFM), while compositional and bond
formation analysis were carried out using X-photoelectron (XPS) and Fourier transform infrared spectroscopy
(FT-IR), respectively. Structural characterization of catalysts was performed using the X-ray diffraction (XRD)
technique. It was observed that nanoparticles produced during laser ablation process act as active centers in
the catalyst films, producing significantly higher rate (about 6 times) of H2 generation than the corresponding
Co−B powder. No significant changes were observed for Co−B powder treated in an inert atmosphere (vacuum
and Ar) while it caused structural changes in Co−B films. Co2B phase formation in films makes them more
efficient catalysts with 28% increase in rate of H2 generation as compared to untreated film. Heat treatment
in an oxygen atmosphere causes complete inactivation of powder catalyst, while film still showed excellent
catalytic activity with just a longer induction time. The AFM and SEM analysis of the heat-treated films did
not show drastic change in surface morphology, indicating that changes in catalytic activity of the films were
possibly connected to structural modification and formation of boron oxide on the catalyst surface. We report
that by using suitable thin film Co−B catalyst the maximum H2 generation rate of about 5000 mL/(min g of
catalyst) can be achieved. This can generate about 0.9 kW (0.7 V) for proton exchange membrane fuel cells
(PEMFC), a critical requirement for portable devices.
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