Abstract:
Morphologically tuned cobalt tungstate
(CoWO4), a new entrant toward borohydride oxidation
reaction (BOR), was explored as it exhibited negligible H2
evolution while enabling rapid BOR. A simple synthetic
strategy was employed and fine-tuned to obtain different
morphologies of CoWO4 whose urchin-shaped variant gave
exciting activity toward BOR. An early and quite negative
onset potential of −1.14 V was observed giving a maximum
obtainable specific current density of 105.3 mA mg−1
. The
synthesized variants were investigated in depth by various
electrochemical measurements and assessed in light of
previous reports toward BOR activity. Hydrodynamic studies
were also performed to ascertain the nature of these static
electrochemical measurements. Quantitative assessment of the evolved H2, a prominent competitive reaction to BOR, was
performed suggesting minimal interference. The probable origin of such morphology-dependent activity was subsequently
studied in detail by high-resolution transmission electron microscopy (HR-TEM) analysis, revealing nanometric structures in
the urchin-like variant, which enhance the obtainable BOR activity.
