posted on 2017-02-20, 00:00authored bySengeni Anantharaj, Jeevarathinam Kennedy, Subrata Kundu
Molecular hydrogen
(H2) generation through water splitting with minimum energy
loss has become practically possible due to the recent evolution of
high-performance electrocatalysts. In this study, we fabricated,
evaluated, and presented such a high-performance catalyst which is
the Ni3Se4 nanoassemblies that can efficiently
catalyze water splitting in neutral and alkaline media. A hierarchical
nanoassembly of Ni3Se4 was fabricated by functionalizing
the surface-cleaned Ni foam using NaHSe solution as the Se source
with the assistance of microwave irradiation (300 W) for 3 min followed
by 5 h of aging at room temperature (RT). The fabricated Ni3Se4 nanoassemblies were subjected to catalyze water electrolysis
in neutral and alkaline media. For a defined current density of 50
mA cm–2, the Ni3Se4 nanoassemblies
required very low overpotentials for the oxygen evolution reaction
(OER), viz., 232, 244, and 321 mV at pH 14.5, 14.0, and 13.0 respectively.
The associated lower Tafel slope values (33, 30, and 40 mV dec–1) indicate the faster OER kinetics on Ni3Se4 surfaces in alkaline media. Similarly, in the hydrogen
evolution reaction (HER), for a defined current density of 50 mA cm–2, the Ni3Se4 nanoassemblies
required low overpotentials of 211, 206, and 220 mV at pH 14.5, 14.0,
and 13.0 respectively. The Tafel slopes for HER at pH 14.5, 14.0,
and 13.0 are 165, 156, and 128 mV dec–1, respectively.
A comparative study on both OER and HER was carried out with the state-of-the-art
RuO2 and Pt under identical experimental conditions, the
results of which revealed that our Ni3Se4 is
a far better high-performance catalyst for water splitting. Besides,
the efficiency of Ni3Se4 nanoassemblies in catalyzing
water splitting in neutral solution was carried out, and the results
are better than many previous reports. With these amazing advantages
in fabrication method and in catalyzing water splitting at various
pH, the Ni3Se4 nanoassemblies can be an efficient,
cheaper, nonprecious, and high-performance electrode for water electrolysis
with low overpotentials.