Tailoring Binding Abilities By Incorporating Oxophilic Transition Metals on 3D Nanostructured Ni Arrays for Accelerated Alkaline Hydrogen Evolution Reaction

Abstract

Developing efficient and inexpensive electrocatalysts for the hydrogen evolution reaction (HER) in alkaline water electrolysis plays a key role for renewable hydrogen energy technology. The slow reaction kinetics of HER in alkaline solutions, however, has hampered advances in high-performance hydrogen production. Herein, we investigated the trends in HER activity with respect to the binding energies of Ni-based thin film catalysts by incorporating a series of oxophilic transition metal atoms. It was found that the doping of oxophilic atoms enables the modulation of binding abilities of hydrogen and hydroxyl ions on the Ni surfaces, leading to the first establishment of a volcano relation between OH-binding energies and alkaline HER activities. In particular, Cr-incorporated Ni catalyst shows optimized OH-binding as well as H-binding energies for facilitating water dissociation and improving HER activity in alkaline media. Further enhancement of catalytic performance was achieved by introducing an array of three-dimensional (3D) Ni nanohelixes (NHs) that provide abundant surface active sites and effective channels for charge transfer and mass transport. The Cr dopants incorporated into the Ni NHs accelerate the dissociative adsorption process of water, resulting in remarkably enhanced catalytic activities in alkaline medium. Our approach can provide a rational design strategy and experimental methodology toward efficient bimetallic electrocatalysts for alkaline HER using earth-abundant elements.

MOF-Derived Porous Fe3O4/RuO2-C Composite for Efficient Alkaline Overall Water Splitting

“…(e) The increasing oxophilicity may be a reason for the high catalytic activity. For example, Kim et al 70 reported that the incorporation of oxophilic transition metal on threedimensional (3D) nanostructure Ni array accelerates the hydrogen evolution reaction. Jiao and co-workers reported the role of surface oxophilicity in the water splitting catalyzed by copper.…”

Cerium-Doped Nickel Phosphide Nanosheet Arrays as Highly Efficient Electrocatalysts for the Hydrogen Evolution Reaction in Acidic and Alkaline Conditions

“…Moreover, EIS was also performed to estimate the HER kinetics on the surfaces of the catalysts. 71,72 The lower charge-transfer resistance (R ct ) implies faster electron transfer and the enhanced HER kinetics toward the catalytic reaction. 44,72−74 As shown in the Nyquist plot and equivalent circuit in Figure 3c, the smaller semicircular radius for the Nyquist plot indicates a lower R ct .…”

One-dimensional amorphous cobalt(ii) metal–organic framework nanowire for efficient hydrogen evolution reaction

“…S6 †). 62,63 The small R ct value of the CoCH@Co-MOF-30 demonstrates favorable charge transfer kinetics, therefore implying high HER activity.…”