Impact of the NiO nanostructure morphology on the oxygen evolution reaction catalysis

Highly porous Co-doped NiO nanorods: facile hydrothermal synthesis and electrocatalytic oxygen evolution properties

“…However, the nickel oxide-based OER electrocatalysts are less attractive because of their low efficiency and poor stability [ 22 ]. Some strategies have been proposed to improve the electrocatalytic activity of nickel oxide for the OER such as the introduction of N dopants into NiO nanosheets [ 23 ], embedding nickel/nickel oxide within a N-graphene matrix [ 24 ], designing of rich nickel vacancies within mesoporous nickel oxide [ 25 ] as well as employing different morphological nanostructures [ 26 , 27 ]. Despite tremendous efforts, the development of efficient and robust OER catalysts based on nickel oxide nanostructures is still a great challenge and needs further investigation.…”

Development of Ni‐Ir Oxide Composites as Oxygen Catalysts for an Anion‐Exchange Membrane Water Electrolyzer

“…The current peaks at ≈1.4 V depict the oxidation of Ni 2+ to Ni 3+ . [37,43] The OER overpotentials of IrO 2 -400, Ni-IrO x (1:1), Ni-IrO x (2:1), Ni-IrO x (3:1), Ni-IrO x (5:1), Ni-IrO x (7:1), and NiO were 349, 314, 340, 358, 366, 398, and 427 mV, respectively. An increase in the composition of NiO was followed by an increase in overpotentials of the catalyst, demonstrating the deteriorating OER activity of the catalysts with increasing Ni content.…”

“…The active site in Ni 3+ ions might be the same as NiOOH, (an intermediate of the OER, promoting the electrocatalytic activity for the OER). [37,38] In the Ni-IrO x composites, the difference of the Pauling scale electronegativity between Ir (2.20) and Ni (1.91) may lead to the partial polarization of electrons from Ni to Ir. Hence, compared to pristine NiO, the lower electronic density of NiO in the Ni-IrO x composite catalyst could boost the electrocatalytic activity for the OER.…”

“…An increase in the reaction temperature from 350 to 500 °C was followed by a decrease in the specific surface area of the catalysts and an increase in the proportion of Ni 3+ ions acting as active sites for the OER in NiO. [37,38] According to the opposite effect, the optimized preparation conditions for the OER catalyst would lead to the best activity and the highest stability. The AEM electrolyzer fabricated using Ni-IrO x as the anode composite catalyst and nickel foam as anode gas diffusion layer (GDL) exhibited a current density of 1125.3 mA cm −2 at 1.8 V and 50 °C and an overpotential increment rate of 2.5 mV h −1 under a constant current density of 500 mA cm −2 at 40 °C.…”

Successful CO2 reduction under visible light photocatalysis using porous NiO nanoparticles, an atypical metal oxide

“…1 NiO based electrodes are preferred over various precious metals for their corrosion resistant nature in alkaline media. 2 Compared to other transition metal oxides like MnO 2 , Co 3 O 4 , CuO, Fe x O y etc., NiO is more effective in the oxygen evolution reaction. 2 Thus, nickel oxides and (oxy)hydroxides are promising replacements for noble-metal based materials for several applications.…”