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Abstract
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Among the different available methods, hydrogen production by electrocatalytic water
splitting is the most attractive method. Here, Ag2O/NiO hybrid nanostructures with
different molar ratios of silver and nickel ions were synthesized by co-precipitation
method. Nickel oxide and silver oxide nanostructures was also prepared to compare
with Ag2O/NiO nanocomposites. Investigations indicated that the as-prepared Ag2O/NiO
nanocomposite with an equal molar ratio of metal ions shows high water splitting activity
in 1 M KOH solution and only 430 and 140 mV are needed as overpotentials under a current
density of 10 mA cm2 for oxygen and hydrogen evolution reactions (OER and HER),
respectively. Ag2O/NiO has the largest electrochemically active surface area, the lowest
Tafel slope, the smallest semicircle diameter in the Nyquist plots, and the lowest charge
transfer resistance for both OER and HER among all tested nanomaterials. Furthermore,
Ag2O/NiO showed excellent stability for OER and HER for at least 30 h.
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