Nickel Based Electrocatalysts for Water Electrolysis

Abstract

Current hydrogen production is based on the reforming process leading to the emission of pollutants; therefore, a substitute production method is imminently required. Water electrolysis is an ideal alternative for large-scale hydrogen production, as it does not produce any carbon-based pollutant byproducts. Production of green hydrogen from water electrolysis using intermittent sources (e.g., solar, eolic) would facilitate clean energy storage. However, the electrocatalysts currently required for water electrolysis are noble metals, making this potential option expensive and inaccessible for industrial applications. Therefore, there is a need to develop electrocatalysts based on earth-abundant and low-cost metals. Nickel-based electrocatalysts are a fitting alternative because they are economically accessible. Extensive research has focused on developing nickel-based electrocatalysts for hydrogen and oxygen evolution. Theoretical and experimental work have addressed the elucidation of these electrochemical processes and the role of heteroatoms, structure, and morphology. Even though some works tend to be contradictory, they have lit up the path for efficient nickel-based electrocatalysts. For these reasons, herein, a review of recent progress is presented.

Highly Porous Ni Electrode Decorated with Fe₃O₄for Oxygen Evolution Reaction(OER)

“…A is the area under the I-V curve, k is the scan rate (mV s -1 ), m is an active mass of oxide material (mg), and ΔV is a potential window (mV). In addition, for double-layer capacitance measurements, we set the potential window to a width of 0.1 mV, namely between 0.377 ~ and 0.477, in order to obtain a CV response without a Faradaic reaction at the electrode-electrolyte, so that a more precise measurement is obtained [12]. However, in actual observations, we had difficulty calculating the specific capacitance value precisely because the response of the measurements was inconsistent.…”

“…[11]. Nickel exhibits favourable characteristics as an electrocatalyst due to its notable attributes, including elevated conductivity, thermal stability, and commendable electrical qualities [12]. Typically, nickel (Ni) exists as a divalent cation, although it can adopt various valences within the range of -1 to +4 [13].…”