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.

Adjacent single-atom irons boosting molecular oxygen activation on MnO2

“…The transition state of the catalytic reaction was determined using the climbing image nudged elastic band (Cl-NEB) method 41 , 42 . Zero-point energy correction was obtained from vibrational frequencies by applying normal-mode analysis through DFT calculations 43 . We fixed the catalyst substrate and only allowed the adsorbing molecule to vibrate.…”

Crystal Phase Transition Creates a Highly Active and Stable RuCX Nanosurface for Hydrogen Evolution Reaction in Alkaline Media

“…The charge transfer resistance ( R ct ) is the diameter of semicircle in the low‐frequency zone of EIS, which is related to the electrocatalytic kinetics. [ 26,27 ] The smallest R ct value of the Ru Δc→h /C represents the fastest electrocatalytic faradaic process and electron transfer between the interfaces, thus indicating the highest HER performance among catalysts.…”

Recent Advances in Alkaline Exchange Membrane Water Electrolysis and Electrode Manufacturing

“…Among them, Ni can be considered the most promising catalyst for AEMWE since it can be used both as anodic and as cathodic catalysts for this type of process. Some authors such as Kim J. et al [68] have investigated the HER activity improvement of nickel after adding a series of transition metals such as Fe, Cr, and Ti. They found that the Cr-Ni catalyst shows the highest HER performance in a 1.0 M KOH solution.…”