Materials Advances
·
2024
·
IF 5.2
Xuan Chen,Lin Zhou,Zhanghong Guo,Qijun Song
In this work, malic acid (MA) stabilized iridium nanoparticles (MA-IrNPs) were prepared by one-pot synthesis using MA and IrCl3 as the precursors and NaBH4 as the reducing agent. The as prepared MA-IrNPs have exhibited multi-enzyme activities, especially an excellent laccase-like activity and improved environment adaptability. For the substrate 2,4-dichlorophenol (2,4-DP), a low Km value of 0.117 mM and a high Vmax value of 0.002 mM s−1 were obtained. Under the catalysis of MA-IrNPs, the colourless norepinephrine (NE) can be selectively oxidized by dissolved oxygen to form an orange-brown product and the reaction can be substantially accelerated in the presence of H2O2 due to the synchronic effect of catalase-like and laccase-like activity of MA-IrNPs. Based on this chromogenic reaction, a sensitive colourimetric method was developed for the determination of NE in urine samples. A limit of detection as low as 0.05 μM and a wide linear range of 0.1–120 μM were achieved, showing a promising application potential of MA-IrNPs in disease diagnosis.
研究领域:
生物化学
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医学诊断
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纳米材料
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2023
·
IF 16.5
Yan-Wen Ye,Yi-Ming Hu,Wan-Bin Zheng,Ai-Ping Jia,Yu Wang,Ji-Qing Lu
ABSTRACT Ir nanoparticles (NPs) were synthesized via a colloidal method using tetradecyltrimethyl ammonium bromide (TTAB) as the ligand, and the supported Ir/BN catalysts were employed for selective hydrogenation of crotonaldehyde (CRAL). It was found that by proper thermal treatments, the TTAB-capped Ir NPs were very active and selective for the reaction. The Ir/BN catalyst calcined at 300 °C with surface TTAB residue gave a quasi-steady state turnover frequency (TOF) for crotyl alcohol (CROL) formation of 0.02 s −1 and a CROL selectivity of 94.4%, while that calcined at 500 °C with clean surface gave a TOF of 0.004 s −1 and a CROL selectivity of 56.2%. The Ir-TTAB interface was essential for the enhanced performance. In-situ IR spectra along with kinetic investigation revealed that TTAB improved CRAL adsorption and strengthened C=O adsorption, which accounted for high activity and selectivity. However, high coverage of TTAB on the Ir surface suppressed the H 2 adsorption and consequently lowered the activity. Thus the findings provided useful information on the design of efficient catalysts for selective hydrogenation.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2021
·Vol. 12
·期 3
·1017-1024
·
IF 6.119
Guangxia Jin,Guowei Sun,Cheng Fu,Chan Wang,Guoxia Ran,Qijun Song
Iridium nanoparticles (IrNPs) have shown intriguing enzyme-like activities; however, the mechanism behind their versatile enzymatic behaviors is still elusive. A new kind of IrNPs stabilized with β-cyclodextrin (CD) was prepared in this work, and these IrNPs show oxidase-like, catalase-like and peroxidase-like activities. Their catalytic performances were comprehensively studied both by experimental characterization and theoretical calculations. The obtained results were systematically compared with other previously reported IrNPs. It was found that the catalytic properties of the IrNPs are derived from the lattice planes. All the IrNPs could catalyze the degradation of H2O2 due to the presence of the Ir(111) plane, while only the IrNPs with the Ir(220) plane exhibit oxidase-like activity. First of all, a new mechanism for the catalase-like activity of IrNPs was proposed here. The adsorption of H2O2 on IrNPs induces the breakdown of its O–O bond to form ˙OH radicals. The produced ˙OH will then couple with another ˙OH or H2O2, forming the key intermediate species (˙O or ˙OOH) in the production of O2. According to the energy diagrams of H2O2 decomposition on different Ir planes, we suggest that the catalase-like activity is intrinsic to the Ir(111) plane and is independent of other crystal faces or coating agents. In addition, the radicals (˙OH and ˙OOH) generated on different Ir crystal planes show different stabilities and reactivities, which is responsible for the diverse peroxidase-like activities of IrNPs. Finally, the oxidase-like properties are derived from the Ir(220) plane, where the chemisorbed O2 could accept one electron to generate superoxide species. The mechanism revealed in the present work should be helpful for understanding the catalytic role of the lattice planes of IrNPs, which may also be applicable to other metal nanozymes.
研究领域:
生物化学
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纳米生物学
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2020
·
IF 4.019
Jingru Wang,Shanhui Zhu,Yunwei Wang,Yingyong Wang,Guoqiang Jin,Xili Tong,Xiangyun Guo
The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) under mild condition is a promising but challenging process. Herein, SiC supported Ru-Ir bimetallic catalyst exhibit enhanced catalytic activity for aqueous hydrogenation of LA into GVL under mild conditions. Comparing with monometallic Ir 3 /SiC and Ru 3 /SiC, the conversion of LA over bimetallic Ru 0.5 -Ir 2.5 /SiC catalyst increase from 51.2 % and 45.9% to 100% at 25 °C and 0.2 MPa of H 2 pressure. The enhanced catalytic activity of Ru 0.5 -Ir 2.5 /SiC catalyst originates from the electronic synergistic effect among Ru, Ir and SiC. Due to the electron transfer, electron-richened Ir nanoparticles show stronger ability for H 2 dissociation, and the SiC surface produces more active sites to accommodate hydrogen species that spill over from Ir and Ru. The adsorption and hydrogenation of LA molecules occur on the surface of SiC.
研究领域:
催化化学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2018
·Vol. 5
·期 5
·1121-1125
·
IF 5.106
Luhong Fu,Xiang Zeng,Chaozhang Huang,Ping Cai,Gongzhen Cheng,Wei Luo
The exploration of highly active catalysts with superior stability for overall water splitting has received considerable attention. Although intensive efforts have been made to design numerous electrocatalysts for water splitting in alkaline media, only a few electrocatalysts have been developed for proton exchange membrane (PEM)-based electrolyzers in acidic media. Herein, we report a colloidal synthesis of well dispersed ultrasmall Ir NPs with narrow size distribution, of superior catalytic activity and stability toward HER and OER in acidic media. When further used as both an anode and a cathode for acidic overall water splitting, the as-synthesized monodisperse Ir NPs yield a current density of 10 mA cm−2 at 1.58 V with long-term stability.
研究领域:
材料科学
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电化学
·
能源转换
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2022
·
IF 6.562
Hui Li,Hehe Wei,Longtao Zhang,Zixiang Su,Xueqing Gong
Highly active and durable noble metal-based catalysts for electrochemical hydrogen evolution are crucial for clean and renewable energy production, however, low abundance and high price hinder their development at industrial scale. Herein, we synthesized carbon-supported ultrafine iridium nanoparticles (Ir NPs/C) catalyst via solvothermal method which achieved ultralow overpotentials of 13 and 57 mV at the current density of 10 and 100 mA cm −2 for hydrogen evolution reaction (HER) in acidic media, respectively. The prepared Ir NPs/C catalyst also exhibited ultrahigh mass activity of 44.5 A mg −1 at the overpotential of 40 mV and outstanding long-term stability in HER performance for 12 h, remarkably superior to state-of-the-art commercial Pt/C catalyst (3.3 A mg −1 , fast decay) and commercial Ir/C catalyst (1.2 A mg −1 ). Furthermore, it possessed activities toward oxygen evolution reaction (OER) and overall water splitting. This work demonstrates evenly dispersed fine Ir NPs/C catalyst can facilitate highly efficient HER and provides inspiration for rational design of advanced electrocatalysts.
研究领域:
材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Hua Wang,Mei Ming,Min Hu,Caili Xu,Yi Wang,Yun Zhang,Daojiang Gao,Jian Bi,Guangyin Fan,Jin-Song Hu
Developing efficient catalytic materials for electrochemical water splitting is important. Herein, uniformly dispersed and size-controllable iridium (Ir) nanoparticles (NPs) were prepared using a nitrogen-functionalized carbon as the support (Ir/CN). We found that nitrogen functionalization can simultaneously modulate the size of Ir NPs to substantially enhance the catalytically active sites and adjust the electronic structure of Ir, thereby promoting electrocatalytic activity for water splitting. Consequently, the as-synthesized Ir/CN shows excellent electrocatalytic performance with overpotentials of 12 and 265 mV for hydrogen and oxygen evolution reactions in basic medium, respectively. These findings may pave the way for designing and synthesizing other similar materials as efficient catalysts for electrochemical water splitting.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Ye Zhang,Xia Kang,Dong-Xue Liu,Ze-Yu Chen
In recent years, hydrazine borane (HB) as an excellent hydrogen material has been extensively studied by researchers because of its substantial hydrogen content (15.4 wt%), favourable chemical stability, eco-friendliness and being easy to synthesize. With Higher activity, catalysts of HB dehydrogenation will undoubtedly be more desirable for practical applications. In this work, CoIr nanoparticles (NPs) are successfully immobilized on TiO 2 substrate, achieving outstanding catalytic performance and 100% conversion for HB dehydrogenation. Particularly, Co 0.6 Ir 0.4 /TiO 2 can complete the reaction for HB dehydrogenation at 323 K within 32 s (0.53 min), and shows a fairly high turnover frequency (TOF) value (5625 h −1 ), which is higher than the values achieved by most Ni-based catalysts reported so far in the same condition. This superior catalytic performance can be attributed to uniform dispersion of metal NPs with small size and strong interaction among the CoIr NPs and the substrate. It is unquestionable that our work will help to promote the use of HB as a promising hydrogen storage material for fuel cells.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 9
·3113-3119
·
IF 4.58
Cui Malin,Zhao Yuan,Wang Chan,Song Qijun
Iridium nanoparticles (IrNPs) with intrinsic oxidase-like activity were synthesized by using sodium citrate as the stabilizer and NaBH 4 as the reducing agent. The IrNPs have an average diameter of 2.5 ± 0.5 nm and exhibit excellent oxidase-like property. Under the catalytic action of the IrNPs, 3,3′,5,5′-tetramethylbenzidine (TMB) is oxidized by dissolved oxygen (DO) to form a blue product with an absorption maximum at 652 nm. The catalytic activity is ascribed to the production of superoxide anion radical (O 2 ˉ∙). The chromogenic reaction is exploited for the determination of DO. The method exhibits a wide calibration range from 12.5 to 257.5 μM of DO and a limit of detection as low as 4.7 μM. Compared to other methods, this method presented here shows improved precision and faster response time.
Iridium nanoparticles (IrNPs) stabilized by sodium citrate exhibit oxidase-like activity and can effectively catalyze dissolved oxygen (DO) by oxidizing 3,3′,5,5′-tetramethylbenzidine (TMB) to form a blue product.
研究领域:
分析化学
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纳米材料科学
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生物化学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 42
·18274-18280
·
IF 3.288
Malin Cui,Xiaojing Huang,Xiaoyan Zhang,Qingfan Xie,Dapeng Yang
Ultra-small noble metal iridium nanoparticles (IrNPs) possessing superior catalytic activity were prepared using tannin as a stabilizer via a controlled one-step synthesis. Their average size was about 3.5 ± 0.5 nm, and they were enclosed with high-index facets {200} and {311}. They possessed high catalytic activity and could be applied in the efficient and selective catalytic reduction of nitroarenes under mild reaction conditions for the first time. The catalytic reduction rates of different nitroaromatic compounds including 4-nitrophenol (p-NP), p-nitrotoluene (p-NT), p-nitroaniline (p-NA), 4-nitrobenzoic acid (p-NBA) and 4-nitrochlorobenzene (p-NCB) were compared to investigate the reduction mechanism of the IrNPs. The results indicate that catalytic reduction rates were in the order p-NBA > p-NCB > p-NT > p-NP > p-NA. The nitroarenes with electron-withdrawing substituents can be reduced faster than those the electron-donating substituents, suggesting that an electron transfer mechanism was involved in the system of nitroaromatic compound-NaBH4-nanomaterials.
研究领域:
化学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Lingya Yi,Bomin Feng,Nan Chen,Wei Li,Junying Li,Changxiang Fang,Yunxi Yao,Weihua Hu
Heteroatom-doped carbon is a type of promising support for catalytically active metal nanoparticles as it offers abundant anchoring sites to facilitate the nucleation and growth of the nanoparticles, and to strengthen their attachment and more importantly, to enhance their intrinsic catalytic activity via support-metal electronic interaction. In this work, graphene sheets were doped with abundant N atoms via radio-frequency N 2 plasma process and used as unique support to load ultrasmall iridium nanoparticles. As-synthesized Ir@N-G-600 shows excellent activity and stability toward HER and OER in both acidic and alkaline media. At much lower precious metal loading, it is superior to commercial Pt/C, RuO 2 and Ir/C catalysts in terms of HER and OER activity, respectively. As a bifunctional electrocatalyst, Ir@N-G-600 enables efficient overall water splitting in acid and alkaline solutions. The enhanced electrocatalytic activity of Ir@N-G-600 is found to be tightly associated with the strong coordination between Ir atoms and N dopants, which enriches the electron density of Ir atoms to form an optimal electronic configuration for HER and OER processes.
研究领域:
材料科学
·
电催化
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Malin Cui,Jingdan Zhou,Yuan Zhao,Qijun Song
A facile and efficient method was developed for the preparation of iridium nanoparticles (Ir NPs) with superior peroxidase-like activity. Under the catalytic action of the Ir NPs, the peroxidase substrate 3,3,5,5-tetramathylbenzidine (TMB) can be oxidized by H 2 O 2 to form a blue-colored production oxTMB. Kinetic analysis indicated that the catalytic behavior was in accordance with the typical Michaelis-Menten kinetics and the catalytic reaction followed the ping-pang mechanism. Electron Spin Resonance (ESR) experiment showed that no hydroxyl radical formed in the reaction process. Peroxide substrates with different electron withdrawing ability (benzoyl peroxide, H 2 O 2 and artemisinin) were used to study the catalytic reactions and results indicated that H 2 O 2 can oxidize TMB with much faster rate than artemisinin and slower rate than benzoyl peroxide. These results suggest an electron transfer mechanism was involved in the system of TMB-H 2 O 2 -Ir NPs. By using TMB as the colorimetric substrate, H 2 O 2 can be rapidly determined and the method was extended for the determination of xanthine based on its production of H 2 O 2 in the presence of xanthine oxidase. The prepared Ir NPs exhibit good stability in wide range of pH and temperature. The Ir NPs retained at least 90% of their initial catalytic activity after stored at ambient temperature for three months. The high specificity for H 2 O 2 and the excellent stability of the peroxidase-like Ir NPs showed the great application potential in biotechnology field.
研究领域:
生物化学
·
分析化学
·
纳米材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）