Enhancing the Surface-Active Sites of Bimetallic 2D Hydroxide Materials by Introducing Fe²⁺ Ions toward Effective Hydroxide Adsorption for the Water Oxidation Reaction

Abstract

Here, in this work, via a simple wet chemical method, we have modified the CoFe layered double hydroxide (LDH) surface by doping active Fe 2+ ions which function as an excellent electrocatalyst for the oxygen evolution reaction (OER) in 1 M KOH. Variations in the amount of Fe 2+ ions show a noteworthy concentration dependency on the electrochemical performance of the catalyst. The catalyst shows an interesting Fe 2+ ion dependency toward the OER, and a volcanic relationship between accumulated electronic charge and thermoneutral current densities is observed. This volcanic relation shows that with an optimum concentration of Fe 2+ ions, the catalyst could effectively catalyze the OER by following the Sabatier principle of ion adsorption. The LDH having an intermediate amount of Fe 2+ loading {Fe II -LDH (0.04 M)} shows the highest OER activity, and it demands just a 268 mV overpotential to drive a 10 mA/cm 2 current density, whereas the pristine CoFe-LDH displays an overpotential of 345 mV. Also, as a result of introducing Fe 2+ ions, a 4fold increase in the turnover frequency (TOF) value was noticed. Operando in situ impedance analysis reveals that the introduction of Fe 2+ ions in the pristine CoFe-LDH lattice largely improvises the charge transfer kinetics at the interface by providing a greater number of surface-active sites toward OH − adsorption. Overall, this study shows an interesting Fe 2+ ion loading dependency over the LDH surface toward the water oxidation reaction.

Construction of Heterostructure between Ni17W3 and WO2 to Boost the Hydrogen Oxidation Reaction in Alkaline Medium

“…(Figure S18, SI). , As a result, Ni 17 W 3 /WO 2 /rGO exhibits efficient activity and faster kinetics, as well as high stability toward HER in alkaline media when compared with comparisons …”

Tetranuclear CoII4O4 Cubane Complex: Effective Catalyst Toward Electrochemical Water Oxidation

“…In addition to that, the bode plot was verified and described in Figure 5c,d. 44 The Bode figure provided an explanation for the region where hydroxide adsorption and desorption occurred over the electrode surfaces.…”

Deciphering the amplification of dual catalytic active sites of Se-doped NiV LDH in water electrolysis: a hidden gem exposure of anion doping at the core-lattice LDH framework

“…6c displays the EIS of the prepared catalysts and the fitted impedance equivalent circuit model to assess the charge transfer efficiency. 47 On the contrary with the purpose of knowing the effectiveness and efficiency of the product formation of the prepared catalysts, the TOF (turnover frequency) value was calculated from cyclic voltammetry (CV), taking into consideration the peak current, surface concentration from the redox area, and number of electron transfer throughout the process. The calculations of evaluating the TOF value for both OER and HER are provided in the ESI section† where for OER, the TOF value was verified at 1.55 V, and for HER the same was 0.23 V vs. RHE.…”