Hydrogen and oxygen production on Ag2O/NiO hybrid nanostructures via electrochemical water splitting

Abstract

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 cm−2 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.