APPLIED SURFACE SCIENCE
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2023
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IF 6.7
Liming Dai,Chenchen Fang,Fanglei Yao,Xiaoyuan Zhang,Xuefeng Xu,Shangling Han,Jingyao Deng,Junwu Zhu,Jingwen Sun
In-situ generated hydroxides and oxyhydroxides have been gradually recognized as the real active sites of metal organic frameworks (MOFs) towards the oxygen evolution reaction (OER). Nevertheless, the fine phase evolution process is still less of concern and elusive. Herein, we successfully construct serious of Ni-MOFs with differing thickness ranging from 1 nm to 270 nm through a competitive coordination strategy. Utilizing the operando resonance spectroscopy, an accurate phase inversion behavior of the Ni-MOFs has been witnessed during the OER, and demonstrated as a thickness-dependent process. Ultrathin architecture is identified as a positive factor to promote the exchange between MOFs ligands and applied electrolyte during the electrochemical test. Hence, after removing most of the internal ligands, 2D MOFs favor to be transformed as β-NiOOH, which is more active than the generated γ-NiOOH in bulky system. The density function theory (DFT) calculation alongside with the in-situ electrochemistry tests further affirm the β/γ-NiOOH transformation behavior. This work offers a new understanding of the electrocatalytic mechanism from the view point of phase evolution in 2D MOFs.
研究领域:
材料科学
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电化学
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DOI
高影响因子
Journal of Materials Chemistry A
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2025
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IF 9.5
Gouda Helal,Zhenhang Xu,Wei Zuo,Jun Qian,Gongzhen Cheng,Pingping Zhao
Transition metal-based electrocatalysts undergo electrochemical surface reconstruction to generate metal oxy-hydroxide-based hybrids, which regard the actual active sites for the oxygen evolution reaction (OER). Many efforts have been devoted to understanding the electrochemical surface reconstruction, but there is rare research to identify the origin of improved OER performance derived from the substrate. Herein, we reported the electrochemical synthesis of an amorphous γ-NiOOH surface layer on NiFealloy/NiFeN pre-catalysts for efficient water oxidation. However, the conversion of β-NiOOH to γ-NiOOH is a thermodynamically unfavorable process, resulting in much higher applied potential to drive the reaction and subsequently catalyze OER.We identified that the NiFe-bimetallic active sites can promote the OER catalytic activity more than the Ni-monometallic active sites. Besides, nitrogen can reduce the potential required to generate γ-NiOOH OER-active sites from β-NiOOH and generate the NO3- anion, which promotes the formation of γ-NiOOH. The electrochemical analysis and in situ spectroscopic approaches, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), and Raman, reveal that Ni species in NiFealloy/NiFeN are more thermodynamically favorable to form γ-NiOOH than in Nialloy/NiN and NiFeLDH. Beside the electrochemical behavior, X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and bode plots further demonstrate that Fe doping and nitrogen significantly increase the electrochemically active sites. Additionally, DFT calculation results show that the electronic structure of the catalysts is modulated by Fe doping, and the surface reconstruction optimized the adsorption energy of oxygen-containing species and enhanced the OER catalytic activity. This work provides a new design for constructing transition metal-based electrocatalysts for water oxidation.
研究领域:
电化学
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材料科学
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催化化学
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DOI
高影响因子
DALTON TRANSACTIONS
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2023
·Vol. 52
·期 46
·17273-17278
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IF 4
Li Zhang,Hong-Lin Zhu,Zhong-Yi Li,Yue-Qing Zheng
The exploitation of highly active and stable catalysts for reduction of CO2 and water oxidation is one of the approaches to facilitate scalable and sustainable CO2 reduction potentially at the industrial scale. Herein, a feasible strategy to rationally build an overall CO2 + H2O electrocatalytic reaction device is the preparation and matchup of a high-performance CO2 reduction catalyst and low-cost and highly active oxygen anode catalyst. A heterostructured nanosheet, γ-NiOOH/NiCO3/Ni(HCOO)2, exhibited superior catalytic activity in the oxygen evolution reaction, and was integrated with CoPc/Fe–N–C to build an overall CO2 + H2O cell with a current density of 10 mA cm−2 at a very low cell voltage of 1.97 V, and the faradaic deficiency of CO2 to CO was maintained at greater than 90% at 1.9 V.
研究领域:
能源化学
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催化化学
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DOI
PubMed
高影响因子
Electrocatalysis
·
2021
·Vol. 13
·期 1
·37-46
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IF 2.713
He Xiong,Liu Baosheng,Zhang Shaohui,Li Hongda,Liu Jinghua,Sun Zijun,Chang Haixin
Herein, vertically aligned nickel nitrate hydroxide (NiNH) holey nanosheet arrays are controllably in situ grown on nickel foam (NF) via a facile one-step solvothermal method. Unique architecture constructed with two-dimensional (2D) holey nanosheets provides high exposure of active sites and benefits mass transport of electrolyte, which is favorable for OER electrocatalysis. Holey structure maintains through the structural conversion from NiNH to γ-NiOOH during OER activation. The vertically aligned γ-NiOOH porous nanosheet arrays exhibit tight adhesion on NF and sufficient Ni 2+ /Ni 3+ redox species, which guarantee OER activity and durable stability. Optimal OER activity with overpotential of 231 mV at 50 mA/cm 2 , a Tafel slope of 123 mV/dec and a good stability can be achieved in 1 M KOH solution, which is superior to most previous reported transition metal-based electrocatalysts. Our work can provide a facile strategy to obtain highly efficient holey OER electrocatalysts. Graphic Abstract
研究领域:
材料科学
·
电化学
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2026
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IF 9.6
Ze Wang,Wenxiang Wang,Lifang Shi,Man Zhao,Wei Wen,Liwu Qiang,Shuai He,Na Gao,Qinyun Yan,He Xiao,Jianfeng Jia
A two-step strategy of electrosynthesis-solvothermal process builds NiMo/G composites with Ni-O-Mo bridges. • Mo acts as interfacial electron pump, locking Ni in high-valent state. • Electron modulation lowers γ-NiOOH formation barrier by ∼150 mV and CH 3 O → CH 2 O step to 0.46 eV. • NiMo/G delivers 320.6 ± 5.2 mA cm −2 and 15,638.9 ± 254.1 mA mg Ni −1 , enabling low-overpotential formate pathway. The intrinsic instability of the active γ-NiOOH phase severely limits the performance of nickel-based electrocatalysts for the methanol oxidation reaction (MOR). Herein, we report a Mo-induced interfacial electron pump strategy to stabilize the γ-NiOOH lattice and boost MOR efficiency. Via a distinctive two-step strategy of electrolysis and subsequent solvothermal reaction, we construct NiMo/graphene (NiMo/G) composites rich in Ni-O-Mo interfaces, where Mo centers continuously withdraw electrons from adjacent Ni sites, functioning as efficient electron sinks. This precise electronic modulation lowers the thermodynamic barrier for γ-NiOOH formation by ∼150 mV and optimizes the adsorption energetics for intermediates, reducing the energy barrier of the rate-determining *CH 3 O → *CH 2 O step from 0.68 to 0.46 eV, thereby directing the reaction along a low-overpotential formate pathway. Consequently, this optimized NiMo/G catalyst achieves exceptional area activity of 320.6 ± 5.2 mA cm −2 and mass activity of 15,638.9 ± 254.1 mA mg Ni −1 , respectively. This work establishes interfacial electron pump engineering as a general and powerful strategy for stabilizing high-valent active phases in advanced energy conversion and storage technologies. Download: Download high-res image (183KB) Download: Download full-size image
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高影响因子
ADVANCED MATERIALS
·
2021
·Vol. 33
·期 11
·2005587
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IF 30.849
Ke Wang,Hongfang Du,Song He,Lei Liu,Kai Yang,Jinmeng Sun,Yuhang Liu,Zhuzhu Du,Linghai Xie,Wei Ai,Wei Huang
Layered γ-type iron oxyhydroxide (γ-FeOOH) is a promising material for various applications; however, its sheet-shaped structure often suffers from instability that results in aggregation and leads to inferior performance. Herein, a kinetically controlled hydrolysis strategy is proposed for the scalable synthesis of γ-FeOOH nanosheets arrays (NAs) with enhanced structural stability on diverse substrates at ambient conditions. The underlying mechanisms for the growth of γ-FeOOH NAs associated with their structural evolution are systematically elucidated by alkalinity-controlled synthesis and time-dependent experiments. As a proof-of-concept application, γ-FeOOH NAs are developed as electrocatalysts for the oxygen evolution reaction (OER), where the sample grown on nickel foam (NF) exhibits superior performance of high catalytic current density, small Tafel slope, and exceptional durability, which is among the top level of FeOOH-based electrocatalysts. Density functional theory calculations suggest that γ-NiOOH in situ generated from the electrooxidation of NF would induce charge accumulation on the Fe sites of γ-FeOOH NAs, leading to enhanced OER intermediates adsorption for water splitting. This work affords a new technique to rationally design and synthesize γ-FeOOH NAs for various applications.
研究领域:
材料科学
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电化学
·
理论计算
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DOI
PubMed
高影响因子
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