Nanomaterials
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2022
·Vol. 12
·期 13
·2215
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IF 5.719
Huijun Song,Jingjing Li,Guan Sheng,Yinling Zhang,Ahmad Azmin Mohamad,Juan Luo,Zhangnan Zhong,Wei Shao
The oxygen evolution reaction (OER) occurs at the anode in numerous electrochemical reactions and plays an important role due to the nature of proton-coupled electron transfer. However, the high voltage requirement and low stability of the OER dramatically limits the total energy converting efficiency. Recently, electrocatalysts based on multi-metal oxyhydroxides have been reported as excellent substitutes for commercial noble metal catalysts due to their outstanding OER activities. However, normal synthesis routes lead to either the encapsulation of excessively active sites or aggregation during the electrolysis. To this end, we design a novel core–shell structure integrating CoMoO4as support frameworks covered with two-dimensional γ-FeOOH nanosheets on the surface. By involving CoMoO4, the electrochemically active surface area is significantly enhanced. Additionally, Co atoms immerge into the γ-FeOOH nanosheet, tuning its electronic structure and providing additional active sites. More importantly, the catalysts exhibit excellent OER catalytic performance, reducing overpotentials to merely 243.1 mV a versus 10 mA cm−2. The current strategy contributes to advancing the frontiers of new types of OER electrocatalysts by applying a proper support as a multi-functional platform.Keywords:γ-FeOOH nanosheets;CoMoO4@γ-FeOOH heterojunction;oxygen evolution reaction
研究领域:
材料科学
·
电化学
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DOI
PubMed
高影响因子
Frontiers in Chemistry
·
2019
·
IF 3.782
Li Zhanyi,Liu Guoguang,Su Qing,Lv Chunyan,Jin Xiaoyu,Wen Xiaoqing
Naproxen (NPX) is one of the most common pharmaceutical and personal care products found in surface water, which is recalcitrant to degradation by biological treatment or complete removal via traditional sewage treatment processes. In this study, nanoscale γ-FeOOH was synthesized and characterized by X-ray diffraction, scanning electron microscopy, surface analysis, and analysis of the forbidden bandwidth. Under UV irradiation, γ-FeOOH had the capacity to rapidly photodegrade NPX. The photodegradation rate of NPX was dependent on the concentration of γ-FeOOH in solution, initial NPX concentration, and pH. By increasing the concentration of γ-FeOOH, the NPX photodegradation rate was increased and then remained stable. Furthermore, the highest photodegradation rate for NPX was observed under acidic conditions. Through the analysis of the active substances (such as h+, e−, OH, 1O2, and O2·-) by electron spin resonance, the photocatalytic mechanism of NPX degradation on γ-FeOOH was determined to be semiconductor photocatalysis.
研究领域:
环境科学
·
药学
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DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Yifan Wang,Zhengjie Peng,Youqing Yang,Zhonnan Li,Yujiao Wen,Meng Liu,Shikai Li,Lezhu Su,Zhi Zhou,Yongfa Zhu,Nan Zhou
The abuse of agrochemicals has caused serious environmental pollution, raising urgently requirement for sensitive controlled release systems. Biochar supported γ-FeOOH nanoarrays (γ-FeOOH@BC) were synthesized in situ through a two-step pyrolyzation-oxidation procedure. The decoration of γ-FeOOH nanoarray structure significantly enhanced the surface positive charge of the composite (pH zpc increased from 2.7 to 7.8), due to which active substances could be electrostatically self-assembled on γ-FeOOH@BC to realize accurate release by changing the environmental pH. The assembled amounts of QNC and PO 4 3- could reach a value of 94 mg·g −1 and 92 mg·g −1 respectively, and the encapsulation efficiency as well as the release concentration were closely related to the pKa of the substance. 45% (QNC) and 63% (PO 4 3- ) could be released at pH = 7.8 and finally both reached to 88% at pH = 11. After 5 rounds of the sensitivity test, QNC/ PO 4 3- could be well assembled or released by pH adjustment, and the encapsulation efficiency remained above 75%. Meanwhile, the assembly structures could also be self-formed in real soil containing QNC/PO 4 3- and had selective herbicidal activity on barnyard grass plants. This work not only provides a feasible material but also a novel method for self-assembly and controlled release of agricultural chemicals.
研究领域:
环境科学
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农业科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Yuezhu Wang,Hanmin Zhang,Baikun Li,Mingchuan Yu,Ran Zhao,Xiaotong Xu,Lu Cai
Novel γ-FeOOH graphene polyacrylamide carbonized aerogel (γ-FeOOH GPCA) was used as the cathode in neutral electro-Fenton (EF) process to achieve degradation and mineralization of sulfamethoxazole (SMX). γ-FeOOH GPCA cathode was fabricated by a multiple-phase carbonization method, leading to a good conductivity (26.37 Sm −1 with 7.5 mg mL −1 GO) and high electrochemically active surface area (EASA). An in situ synthesis method of γ-FeOOH was accomplished to distribute the catalyst uniformly and firmly into the carbonized aerogel framework. Two electron reduction could take place at the cathode, H 2 O 2 and Fe 2+ can be generated at GPCA cathode efficiently. A 5-batch comparative assessment between GPCA-EF and CF-EF process exhibited the distinguished catalytic stability of GPCA cathode with a total organic carbon (TOC) removal efficiency of 89.8 ± 0.8%, 89.1 ± 0.9% and 84.7 ± 1.1% at the last 3 batches, respectively, versus 61.2 ± 1.2, 60.9 ± 1.1 and 59.4 ± 0.9% by CF cathode. This carbonized aerogel cathode demonstrated a great potential for the EF process to remove organic pollutants in water at neutral pH.
研究领域:
环境科学
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材料科学
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化学工程
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DOI
高影响因子
ADVANCED MATERIALS
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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
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理论计算
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DOI
PubMed
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 13
·7269-7279
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IF 2.936
Junyu Fan,Zhiwei Zhao,Zhaoxia Ding,Jie Liu
In this study, different crystalline structures of FeOOH have been prepared. α-FeOOH was synthesized through a hydrothermal method, whereas β-FeOOH was synthesized via a direct hydrolysis method. Moreover, γ- and δ-FeOOH were prepared by precipitation methods through slow and quick oxidation, respectively. On this basis, their crystal structure, morphology, and surface area were measured. Then, all the synthesized materials were applied to activate peroxymonosulfate (PMS) to generate sulfate radicals (SO4−˙) for acid orange 7(AO7) degradation. Compared with α-FeOOH, β-FeOOH, and γ-FeOOH, δ-FeOOH showed more efficient decolorization of AO7 in the catalytic system because of its abundant surface area and crystalline structure. The effects of several parameters in the δ-FeOOH/PMS/AO7 system were investigated. The results show that the initial pH, which is related to the features of surface hydroxyl groups, is the decisive factor, and excellent catalytic activity is maintained in the pH range 5–8. The increase of catalyst dosage and appropriate increase of PMS concentration contributed to promote the degradation effect. However, self-quenching was observed in a high PMS concentration system. Moreover, δ-FeOOH was stable after six consecutive cycles, and the leaching of iron ions was negligible. According to the quenching test and electron spin resonance analysis, both SO4−˙ and ˙OH were the dominant radicals for AO7 degradation.
研究领域:
环境科学
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催化
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水处理
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DOI
PubMed
高影响因子
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