In-situ probing the rapid reconstruction of FeOOH-decorated NiMoO4 nanowires with boosted oxygen evolution activity

Hao, Hongru; Liu, Ying; Wu, Yanyan; Wang, Zhe; Yuan, Mengke; Miao, Jipeng; Lv, Zhe; Xu, Lingling; Wei, Bo

doi:10.1016/j.mtener.2021.100887

Cited by 20 publications

(27 citation statements)

References 47 publications

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“…After 12 h of OER-CA, the FESEM image of the NiMoO 4 /NF revealed that the rod-shaped morphology is still retained but the surface of these particles has been vigorously ruptured (Figure 9d). 87 The SEM-EDX elemental mapping confirmed that a less percentage of Mo was present in the material after 12 h of OER-CA (Figure 9e−h). The EDX spectrum also suggested the appreciably low Mo count as compared to Ni and oxygen (Figure S21).…”

Section: ■ Introductionmentioning

confidence: 69%

“…On the contrary, only 3.8% of W was found to be leached into the electrolyte even after 12 h of OER-CA with the fresh NiWO 4 /NF anode. As a result of Mo leaching from the highly ordered NiMoO 4 , the surface of newly formed NiO(OH) ED perhaps becomes rougher, which causes enhanced surface area and favors the better penetration of the electrolyte . To prove the presence of the leached Mo oxyanion counterpart in the form of [MoO 4 ] 2– in the electrolyte, a qualitative wet-test using phosphate (PO 4 3– ) and nitric acid (HNO 3 ) was performed using the electrolyte obtained after 12 h of CA.…”

Section: Resultsmentioning

confidence: 99%

“…As a result of Mo leaching from the highly ordered NiMoO 4 , the surface of newly formed NiO(OH) ED perhaps becomes rougher, which causes enhanced surface area and favors the better penetration of the electrolyte. 87 To prove the presence of the leached Mo oxyanion counterpart in the form of [MoO 4 ] 2− in the electrolyte, a qualitative wet-test using phosphate (PO 4 3− ) and nitric acid (HNO 3 ) was performed using the electrolyte obtained after 12 h of CA. The addition of an equal volume of conc.HNO 3 and excess K 2 HPO 4 (aqueous solution) to the electrolyte, followed by mild warming of the solution for a while (15 min), led to the formation of a canary yellow color, characteristic of the polyoxomolybdate anion, [PMo 12 O 40 ] 3− (Figure S20 and discussion therein).…”

Section: ■ Introductionmentioning

confidence: 99%

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Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

2022

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Nickel-based bimetallic oxides such as NiMoO 4 and NiWO 4 , when deposited on the electrode substrate, show remarkable activity toward the electrocatalytic oxygen evolution reaction (OER). The stability of such nanostructures is nevertheless speculative, and catalytically active species have been less explored. Herein, NiMoO 4 nanorods and NiWO 4 nanoparticles are prepared via a solvothermal route and deposited on nickel foam (NF) (NiMoO 4 / NF and NiWO 4 /NF). After ensuring the chemical and structural integrity of the catalysts on electrodes, an OER study has been performed in the alkaline medium. After a few cyclic voltammetry (CV) cycles within the potential window of 1.0−1.9 V (vs reversible hydrogen electrode (RHE)), ex situ Raman analysis of the electrodes infers the formation of NiO(OH) ED (ED: electrochemically derived) from NiMoO 4 precatalyst, while NiWO 4 remains stable. A controlled study, stirring of NiMoO 4 /NF in 1 M KOH without applied potential, confirms that NiMoO 4 hydrolyzes to the isolable NiO, which under a potential bias converts into NiO(OH) ED . Perhaps the more ionic character of the Ni− O−Mo bond in the NiMoO 4 compared to the Ni−O−W bond in NiWO 4 causes the transformation of NiMoO 4 into NiO(OH) ED .A comparison of the OER performance of electrochemically derived NiO(OH) ED , NiWO 4 , ex-situ-prepared Ni(OH) 2 , and NiO(OH) confirmed that in-situ-prepared NiO(OH) ED remained superior with a substantial potential of 238 (±6) mV at 20 mA cm −2 . The notable electrochemical performance of NiO(OH) ED can be attributed to its low Tafel slope value (26 mV dec −1 ), high double-layer capacitance (C dl , 1.21 mF cm −2 ), and a low charge-transfer resistance (R ct , 1.76 Ω). The NiO(OH) ED /NF can further be fabricated as a durable OER anode to deliver a high current density of 25−100 mA cm −2 . Post-characterization of the anode proves the structural integrity of NiO(OH) ED even after 12 h of chronoamperometry at 1.595 V (vs reversible hydrogen electrode (RHE)). The NiO(OH) ED /NF can be a compatible anode to construct an overall water splitting (OWS) electrolyzer that can operate at a cell potential of 1.64 V to reach a current density of 10 mA cm −2 . Similar to that on NF, NiMoO 4 deposited on iron foam (IF) and carbon cloth (CC) also electrochemically converts into NiO(OH) to perform a similar OER activity. This work understandably demonstrates monoclinic NiMoO 4 to be an inherently unstable electro(pre)catalyst, and its structural evolution to polycrystalline NiO(OH) ED succeeding the NiO phase is intrinsic to its superior activity.

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Section: ■ Introductionmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

2022

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“…[23] Therefore, enhancing the binding force between catalyst and support, and the corrosion resistance of catalysts to electrolytes as well as constructing superhydrophilic/superaerophobic surface are key aspects needed to be considered for designing high-current-density electrocatalysts. Beyond that, Fe-based multicomponent catalysts are reported to undergo phase transformation or dissolution-redeposition process under harsh oxidative OER conditions, [24,25] which can reconstruct catalysts with newly formed morphology and increased active sites, leading to superior catalytic activity and stability. [6] Thus, reconstruction engineering on FeOOH-based catalysts is expected to be a promising route to achieve ultrastable OER at high current densities.…”

Section: Introductionmentioning

confidence: 99%

In Situ Reconstructed Zn doped Fe_xNi₍₁₋_x₎OOH Catalyst for Efficient and Ultrastable Oxygen Evolution Reaction at High Current Densities

Zhang

Jin

et al. 2022

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the global energy and environmental issues. [1][2][3] Its half-reaction, oxygen evolution reaction (OER), is considered as the key bottleneck in water splitting owing to its multiple protons and electron transfer. [4,5] Through precious metal oxides such as IrO 2 and RuO 2 exhibit effective OER activity, the scarcity, high cost, and inferior stability hinder their widespread applications. [6] The development of highly active electrocatalysts based on earthabundant elements is a highly promising solution to above predicament. However, at present, few noble-metal-free electrocatalysts can meet the requirements of commercial alkaline water electrolysis: afford the current density of 1000 mA cm −2 with stable operation over 100 h. [7,8] Therefore, developing noble-metal-free electrocatalysts with high efficiency and outstanding durability at the large current densities is imperative yet challenging.Iron (Fe)-based materials, especially FeOOH, have recently drawn great attention as promising OER catalysts due to their abundance, cost-effectiveness, and environmental friendliness. [9][10][11] It is reported that the intrinsic activity of FeOOH for OER is higher than that of NiOOH and CoOOH. [12] Nevertheless, the OER performance of FeOOH is far from satisfactory DevelopingFeOOH as a robust electrocatalyst for high output oxygen evolution reaction (OER) remains challenging due to its low conductivity and dissolvability in alkaline conditions. Herein, it is demonstrated that the robust and high output Zn doped NiOOH-FeOOH (Zn-Fe x Ni (1−x) )OOH catalyst can be derived by electro-oxidation-induced reconstruction from the pre-electrocatalyst of Zn modified Ni metal/FeOOH film supported by nickel foam (NF). In situ Raman and ex situ characterizations elucidate that the pre-electrocatalyst undergoes dynamic reconstruction occurring on both the catalyst surface and underneath metal support during the OER process. That involves the Fe dissolution-redeposition and the merge of Zn doped FeOOH with in situ generated NiOOH from NF support and NiZn alloy nanoparticles. Benefiting from the Zn doping and the covalence interaction of FeOOH-NiOOH, the reconstructed electrode shows superior corrosion resistance, and enhanced catalytic activity as well as bonding force at the catalyst-support interface. Together with the feature of superaerophobic surface, the reconstructed electrode only requires an overpotential of 330 mV at a high-current-density of 1000 mA cm −2 and maintains 97% of its initial activity after 1000 h. This work provides an indepth understanding of electrocatalyst reconstruction during the OER process, which facilitates the design of high-performance OER catalysts.

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“…(b) LSV, (c) overpotential, (e) Tafel slope, (f ) EIS and (g) C dl of AC-FeNi(O)OH, FeNi(O)OH, AC-Fe(O)OH and Fe(O)OH in 1 mol L −1 potassium hydroxide solution (1 M KOH). (d) Comparison of the OER performance of the AC-FeNi(O)OH catalyst with reported Fe-based catalysts at 100 mA cm −2 32,[34][35][36][37][38][39][40][41][42][43].…”

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confidence: 99%

Rapid “self-healing” behavior induced by chloride anions to renew the Fe–Ni(oxy)hydroxide surface for long-term alkaline seawater electrolysis

Fan

Zhang

et al. 2022

Inorg. Chem. Front.

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In-situ probing the rapid reconstruction of FeOOH-decorated NiMoO4 nanowires with boosted oxygen evolution activity

Cited by 20 publications

References 47 publications

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

In Situ Reconstructed Zn doped Fe_xNi₍₁₋_x₎OOH Catalyst for Efficient and Ultrastable Oxygen Evolution Reaction at High Current Densities

Rapid “self-healing” behavior induced by chloride anions to renew the Fe–Ni(oxy)hydroxide surface for long-term alkaline seawater electrolysis

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In-situ probing the rapid reconstruction of FeOOH-decorated NiMoO4 nanowires with boosted oxygen evolution activity

Cited by 20 publications

References 47 publications

Intrinsic Lability of NiMoO4to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO4to Excel the Oxygen Evolution Reaction

In Situ Reconstructed Zn doped FexNi(1−x)OOH Catalyst for Efficient and Ultrastable Oxygen Evolution Reaction at High Current Densities

Rapid “self-healing” behavior induced by chloride anions to renew the Fe–Ni(oxy)hydroxide surface for long-term alkaline seawater electrolysis

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Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

In Situ Reconstructed Zn doped Fe_xNi₍₁₋_x₎OOH Catalyst for Efficient and Ultrastable Oxygen Evolution Reaction at High Current Densities