Nickel Confined in the Interlayer Region of Birnessite: an Active Electrocatalyst for Water Oxidation

Abstract

We report a synthetic method to enhance the electrocatalytic activity of birnessite for the oxygen evolution reaction (OER) by intercalating Ni 2+ ions into the interlayer region. Electrocatalytic studies showed that nickel (7.7 atomic %)-intercalated birnessite exhibits an overpotential (h) of 400 mV for OER at an anodic current of 10 mA cm À2 . This h is significantly lower than the h values for birnessite (h % 700 mV) and the active OER catalyst b-Ni(OH) 2 (h % 550 mV). Molecular dynamics simulations suggest that a competition among the interactions between the nickel cation, water, and birnessite promote redox chemistry in the spatially confined interlayer region.Converting sunlight to useful forms of energy, such as electrical and chemical energy, has the potential to help eliminate the fossil fuel dependence of mankind. [1][2][3][4][5][6] From this standpoint, designing cheap, efficient, and robust catalysts that can facilitate the splitting of water to oxygen and hydrogen is a worthwhile goal that will potentially pave the path for efficient conversion of solar energy to chemical energy. The splitting of water [Eq. (1)] is thermodynamically uphill and a kinetically hindered reaction, which has a high energetic penalty without a catalyst. [7] H 2 O ðlÞ !Inspired by the ability of manganese-bearing photosystem II (PS-II) to split water, there have been numerous studies that have utilized manganese-containing compounds as homogeneous and/or heterogeneous catalysts for the oxygen evolution reaction (OER).

Iron‐Doped Nickel Phosphide Nanosheets In Situ Grown on Nickel Submicrowires as Efficient Electrocatalysts for Oxygen Evolution Reaction

“…Tafel plots with a wide potential range are presented in Figure S7, wherein (Ni 0.87 Fe 0.13 ) 2 P–Ni and RuO 2 show two distinct linear segments. Typically, higher Tafel slopes (≈120 mV dec −1 ) are associated with water adsorption on the catalytic site as the rate‐determining step, whereas lower Tafel slopes (≈40 mV dec −1 ) suggest O−O bond formation as the rate‐determining step . Therefore, both water adsorption and O−O formation are rate‐determining step for (Ni 0.87 Fe 0.13 ) 2 P–Ni and RuO 2 in the high‐potential region, and might be influenced by the reactions in low‐potential region, leading to the different Tafel slopes.…”

Insight into pH‐Dependent Formation of Manganese Oxide Phases in Electrodeposited Catalytic Films Probed by Soft X‐Ray Absorption Spectroscopy

“…Recent studies showed that disturbance of a birnessite structure by doping it with other 3 d transition metals can enhance the catalytic activity of the material . Such a structural disturbance might also be reached by a judicious choice of the parameters in the electrodeposition process.…”

2D Materials with Nanoconfined Fluids for Electrochemical Energy Storage

“…42 Experimental evidence further showed that the intercalation of electrocatalytically active cations into the hydrated interlayer of birnessite MnO 2 led to high activity for the oxygen evolution reaction. 43,44 Once the charge transfer occurs, the ion must diffuse within the electrode material due to the concentration gradient developed between the interface and the bulk of the material. In bulk materials, this is typically accomplished by hopping from vacancy to vacancy, with the activation energy determined by the highest energy transition state between the vacant sites.…”