Advanced electrocatalysts toward
oxygen evolution reaction (OER)
at high current density with low overpotential remain a significant
challenge for electrochemical water splitting. Herein, NiFe-based
catalysts with appropriate electronic conductivity and catalytic activity
have been obtained through introduction of oxygen vacancies by a facile
and economic NaBH4 reduction approach. The combined density
functional theory calculations, physical characterization, and electrochemical
studies disclose that the reductive treatment creates a high amount
of oxygen vacancies, high active sites, and a low energy barrier for
OER. The oxygen vacancy-rich catalyst yields a more than 2-fold increased
current density (from 100 to 240 mA cm–2) at a low
overpotential
of 270 mV, accompanied by good stability under OER conditions. The
approach is also broadly applicable for NiFe compounds synthesized
via different methods or substrates.
A facile hydrogen evolution-assisted electrodeposition method is proposed for fabrication of metal nanoparticles from protic ionic liquids with high electrocatalytic activity. The controlled evolution of hydrogen bubbles functions as physical spacers to prevent aggregation of nanoparticles. Uniform silver, palladium, and nickel nanoparticles with high surface area have been generated and used as catalysts for oxygen reduction reactions with enhanced performance.
A highly
efficient porous NiCu-phosphide (NiCu-P) electrode is
reported for a hydrogen evolution reaction (HER) in acidic, neutral,
and basic electrolytes. The NiCu-P electrode was prepared via hydrogen
bubbles dynamic templated electrodeposition of NiCu alloy onto nickel
mesh, followed by phosphidation. Due to the synergistic interaction
in NiCu-P, the material exhibits excellent HER activity in a wide
pH range from 0.3–14. Current density of −10 mA cm–2 was achieved at low overpotentials of −226,
−250, and −175 mV in 0.5 M H2SO4, 1 M phosphate buffer solution, and 1 M KOH, respectively. The fabricated
NiCu-P electrode also shows an outstanding electrochemical stability,
regardless of electrolyte pH. The NiCu-P has a slope value of −53
mV dec–1, indicating that HER at NiCu-P follows
the Heyrovsky mechanism in 1 M KOH.
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