Unveiling Role of Sulfate Ion in Nickel‐Iron (oxy)Hydroxide with Enhanced Oxygen‐Evolving Performance

Abstract

The rational design of effective catalysts for sluggish oxygen evolution reactions (OERs) is desired but challenging. Nickel-iron (NiFe) (oxy) hydroxides are promising pre-electrocatalysts for alkaline OER. However, OER performances are limited by the slow reconstruction process to generate active species of high-valance NiFe oxyhydroxides. In this work, a sulfate ion (SO 4 2− ) modulated strategy is developed to boost the OER activity of NiFe (oxy)hydroxide by accelerating the electrochemical reconstruction of pre-catalyst and stabilizing the reaction intermediate of OOH* during OER. The SO 4 2− decorated NiFe (oxy)hydroxide catalyst (NF-S0.15) is fabricated via scalable anodization of NiFe foam in a thiourea-dissolved electrolyte. The experimental and theoretical investigations demonstrate the dual effect of SO 4 2− on improving OER performances. SO 4 2− leaching is favorable for the electrochemical reconstruction to form active NiFeOOH under OER condition. Simultaneously, the residual SO 4 2− adsorbed on surface can stabilize the intermediate of OOH*, and thus enhance the OER performances. As expected, NF-S0.15 delivers an ultralow overpotential of 234 mV to reach the current density of 50 mA cm −2 , a fast OER kinetics (27.7 mV dec −1 ), and a high stability for more than 100 h. This unique insights into anionic modification could inspire the development of advanced electrocatalysts for efficient OER.

Ir Single Atom Catalyst Loaded on Amorphous Carbon Materials with High HER Activity

“…The d‐band center of PBN‐300‐Ir is −2.93 eV far away the Fermi level, which is more negative than that of N 3 IrCl by −2.80 eV. [ 33 ] The integral COHP value of Ir–H in PBN‐300‐Ir is −3.04 eV (Figure 5e ), which is less than the relative values of Ir—H bond in N 3 IrCl (−4.44 eV), which further confirms the weak binding between Ir and H atoms on the active surface in PBN‐300‐Ir. [ 34 ] These analysis shows the unique roles of coordinated C atoms around the Ir atoms, and they can facilitate the releasing of H 2 from the absorption center, and therefore improving the efficiency of HER.…”

Fabrication of tailored rod-shaped carbon nitride, g-C3N4, decorated with MoSe2 flowers for the catalytic reduction of nitrophenol, organic dye degradation and biocompatibility studies

“…It is generally known that the semicircle arc with a smaller radius shows lower charge transfer resistance, signifying a facile transfer of interfacial charges over the catalysts. 16,60 From the Nyquist plot, it can be seen that CNM (6 : 1) exhibits the smallest semicircular radius when compared to the other synthesized catalysts, b-CN and MoSe 2 , which implies that the CNM (6 : 1) shows enhanced electronic conductivity due to the lower charge transfer resistance. Lower charge transfer implies higher conductivity and therefore CNM (6 : 1) has the highest ability to promote the transfer of interfacial electrons which is crucial for the reduction reaction of 4-NP to 4-AP.…”

“…These are promising anchoring sites for various cocatalysts and also act as an adsorption site for many smaller molecules. 14 Due to its attractive nature, increasing interest has been developed to study g-C 3 N 4 based materials for various applications including hydrogen (HER)/oxygen evolution reaction (OER), [15][16][17][18] catalysis, 19 degradation of various refractory environmental pollutants, including dyes 8 and harmful nitro-compounds, 20 biological 21 and many chemical transformations. 22 Despite the aforementioned advantages, the pristine g-C 3 N 4 encounters some drawbacks including insufficient active sites and low specific surface area that limits its adsorption performance in catalytic applications.…”

Large‐Scale Synthesis of Spinel NixMn3‐xO4 Solid Solution Immobilized with Iridium Single Atoms for Efficient Alkaline Seawater Electrolysis

“…202200529 Principally, the overall efficiency of water electrolysis is hampered by oxygen evolution reaction (OER) in consideration of its sluggish, multistep protoncoupled electron transfer process. [3] Over the past few years, numerous works have been devoted to explore efficient OER catalysts, including transition metal oxides, [4][5][6] (oxy)hydroxides, [7][8][9] sulfides, [10][11][12] phosphides, [13][14][15] and nitrides. [16][17][18] Moreover, part of them even prevails over the benchmark IrO 2 /RuO 2 in the OER activity and stability, [19][20][21] which certainly invigorates the blossom of the water electrolyzer technique.…”