COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2018
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IF 2.829
Ting Zou,You Han,Xinxue Li,Wei Li,Jinli Zhang,Yan Fu
Controlled synthesis of noble metal nanocatalysts with desirable catalytic activities remains a great challenge. Inspired by electron-rich functional groups and supramolecular assembly properties of natural nucleotides, herein we propose a versatile approach to construct Pd nanocatalysts through employing seven nucleotides as both electron donors and stabilizers . The catalytic performance of nucleotide-Pd complexes are greatly associated with the chemical structures of nucleobases as well as the number of phosphate groups . Guanosine 5′-triphosphate-Pd complexes possess high activities in the hydrogenation reduction of 4-nitrophenol assisted by NaBH 4 , with the relative rate constant of 7770 min −1 mM −1 at 25 °C. Pd(II)-coordinated nucleotides are also promising in NaBH 4 -mediated degradation of organic dyes. This work demonstrates a green and facile process to construct Pd nanocatalysts containing abundant active sites under the assistance by natural nucleotides.
研究领域:
化学
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材料科学
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催化
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2025
·
IF 2.5
Xiong-Li Liu,Jing Lou,Xian-Qiao Zhu,Di-Cheng Pan,De-Wu Liu,Hui-Xian Jing,Wenjing Zhang,Hong-Xing Cen,Guo-Deng Guo-Deng Dong
The development of single chiral source-derived ligands to fine-switch enantioselectivity has continuously attracted the attention in asymmetric catalysis. Herein, we use the same chiral source L-prolinamide as the starting material, synthesizing chiral bidentate pyridine-type N-oxide ligands (denoted as Py-NO) and chiral monodentate phenyl N-oxide ligands (denoted as Ph-NO); their effectiveness was demonstrated in the switch of enantioselectivity in palladium(II)-catalysed Friedel-Crafts (FC) alkylation of indoles and 2,3-dioxopyrrolidines, and both enantiomers of structurally important indole derivatives can be prepared in good yields (up to 91% yield) and high enantioselectivities (up to 99% ee). Key to the success of switch of enantioselectivity is the existence of two different activation patterns in this palladium(II) catalytic system. Experiments demonstrated that a counteranion would plausibly coordinate to the palladium(II) center in the stereoselectivity-determining step. Preliminary mechanistic studies provide a rational explanation for the above observations. This study was the first example of monodentate ligand in asymmetric catalytic Friedel-Crafts alkylation.
研究领域:
不对称催化
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有机合成
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配位化学
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对映选择性化学
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DOI
高影响因子
OPTICS EXPRESS
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2025
·Vol. 33
·期 11
·22185-22195
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IF 3.3
Lu Li,Feng Qin,Zhiguo Zhang,Zhiguo Zhang,Tao Jia
The determination of the energy of the lowest triplet excited state (ET1) for metalloporphyrin photosensitizers, a key parameter for rationalizing energy transfer processes in metalloporphyrins, facilitates a better understanding and optimization of their functionality. In this study, a strategy was proposed for determining the ET1 values in metalloporphyrin systems by analyzing the temperature dependence of the oxygen quenching rate constant using time-resolved spectroscopy, with Platinum(II) octaethylporphyrin (PtOEP) and Palladium(II) octaethylporphyrin (PdOEP) as representative examples. Through a thermal equilibrium approximation of the excited triplet state (T1) and the excited state of oxygen, a theoretical model was introduced in which the oxygen quenching rate exhibits a nonlinear dependence on temperature, enabling the determination of ET1 values. Additionally, the validity of this approach was demonstrated through excitation spectra of metalloporphyrins. Our work provides an effective pathway and offers new insights into the energy-loss mechanisms involved in related photoconversion processes.
研究领域:
物理化学
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光化学
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光谱学
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材料科学
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分子物理学
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产品关联
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
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2022
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IF 7.336
Sijie Gao,Shuozhen Hu,Guoming Luo,Shigang Sun,Xinsheng Zhang
Doping nitrogen (N) into the carbon support was widely applied to enhance the performance of Pd toward formic acid electro-oxidation (FAO). However, traditional nitrogen doping methods can only introduce a low content of nitrogen as well as a two-step complicated procedure to synthesize catalysts. In this study, a facile one-pot strategy is demonstrated to prepare N-doped carbon encapsulated palladium nanoparticles (Pd@N x C) via the pyrolysis of 2,2′-bipyridine palladium (II) complexes. A N-doped carbon layer with the thickness of about 4 nm is in-situ generated over Pd nanoparticles by only one pyrolysis procedure. Both XPS and in-situ XRD results suggest that metallic Pd is reduced from Pd 2+ by the complexed N in bipyridine during the pyrolysis at high temperature. The physical characterizations prove that the in-situ formation of N-doped carbon shell can not only effectively prevent the agglomeration or dissolution of Pd nanoparticles, but also promote the charge donation from the carbon layer to Pd, and maintain the structure of Pd atom complexed to two pyridinic-N atoms (Pd-N). This in-situ synthesis strategy can be successfully applied to carbon supports with different geometry, such as reduced graphene oxide and Vulcan XC-72. Pd@N 3 C/rGO, which contains the highest amount of N (7.39 at.%) and Pd-N (33.15%), shows the highest specific activity (5.88 mA cm −2 ) and excellent durability toward FAO.
研究领域:
材料科学
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电化学
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催化
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Liuzhou Chen,Kun Wu,Mohe Zhang,Nengsheng Liu,Chenxi Li,Jiangzhou Qin,Quanlin Zhao,Zhengfang Ye
A novel chitosan resin microsphere (CDCR) adsorbent, which was synthesized by secondary crosslinking and carbon disulfide modification, and was evaluated for its efficacy in recovering palladium from wastewater. The physicochemical properties and adsorption mechanism of CDCR were determined using scanning electron microscope energy dispersive system (SEM-EDS), fourier-transform infrared spectroscopy (FTIR), simultaneous thermal analyzer (TG-DSC), X-ray photoelectron spectroscopy (XPS), etc. The experimental results showed that its saturated adsorption capacity was about 204.34 mg/g. And the adsorption process of Pd(Ⅱ) was found to be in accordance with the pseudo-second-order kinetic model and the Freundlich model. Thermodynamic analysis indicated that the reaction between CDCR and Pd(Ⅱ) was a spontaneous endothermic process. CDCR showed good reusability, maintaining a Pd(Ⅱ) removal efficiency of 99.99% after eight adsorption–desorption cycles. In the multi-ion coexistence solution, CDCR also exhibited excellent selectivity towards Pd(Ⅱ) adsorption. Furthermore, the adsorption of Pd(Ⅱ) by CDCR was primarily attributed to electrostatic interaction with protonated amine groups and complexation with sulfur groups.
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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产品关联
DOI
高影响因子
FUEL
·
2024
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IF 6.7
Xingyan Liu,Haibo Zhou,Ruolan Li,Maosen Xu,Chenghua Zhang,Zhengsijia Wu,Youzhou He,Xu Zou,Min Fu,Siping Wei
The technology of photolysis water hydrogen evolution driven by solar energy is considered promising to alleviate the energy crisis. However, the low separation and transfer efficiency of photogenerated charge carriers is still one of the challenges leading to the inferior efficiency of photocatalysis. In this paper, alkyl n-hexanoic acid (HA) and aryl benzoic acid (BA) were used as modulators to synthesize HA-PCN-224 and BA-PCN-224 by solvothermal method, in which TCPP linker was coordinated with Zr-O clusters in accompany with part of reserved modulators, respectively. The photocatalytic hydrogen evolution activity of HA-PCN-224 (225.29 μmol·g −1 ·h −1 ) was 2.86 times as that of BA-PCN-224 (78.78 μmol·g −1 ·h −1 ), which should be ascribed to the higher conductivity confirmed by the electrochemical impedance spectroscopy (EIS). Subsequently, the sample HA-PCN-224(Pd) was synthesized by introducing Pd Ⅱ into the porphyrin center. The Photoluminescence (PL), photocurrent response (i-t), Mott-Schottky characterization, and density functional theory (DFT) calculations show that HA-PCN-224(Pd) has excellent electrical conductivity and unique Pd Ⅱ electron bridge, which can significantly accelerate the carrier separation and transfer efficiency. Surprisingly, with the help of Pd Ⅱ as an electron bridge, the photocatalytic hydrogen production activity of HA-PCN-224(Pd) is as high as 20411.32 μmol·g −1 ·h −1 , which is about 90.60 times as that of the original HA-PCN-224. This work provides us with a novel avenue to modulate the conductivity of MOFs via adjusting monocarboxylic acid regulators and introduce unique Pd Ⅱ as the effective electron bridge to promote excellent separation and transfer efficiency of charge carriers for the application in solar energy-related fields.
研究领域:
材料科学
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光化学
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催化
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可再生能源
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Min Shao,Muhan Chen,Mei Fan,Guoting Luo,Ci Jin,Zhangjie Huang
In this study, based on a cyano-functionalized ionic liquid, 1-nitrile-1-octylpyrrole bromide ([C 8 Y 3 Pr]Br), a [C 8 Y 3 Pr]Br/cyclohexane/tributyl phosphate (TBP)/NaCl microemulsion system was constructed and used for the extraction of Pd(II) and preparation of Pd nanoparticles from multimetal solutions. The key extraction parameters including vibration time, [C 8 Y 3 Pr]Br concentration, phase ratio ( R W/O ), and HCl concentration were evaluated. Compared with other ionic-liquid microemulsion systems, the cyano-functionalized ionic liquid [C 8 Y 3 Pr]Br microemulsion system showed excellent extraction performance for Pd(II). Almost all Pd(II) was extracted (>98.0%) from a multimetal solution using the microemulsion system, while the separation factors ( β Pd/M ) of [C 8 Y 3 Pr]Br-based microemulsions for Pd(II) with Cu 2+ , Fe 3+ , Ni 2+ , Zn 2+ , Co 2+ , and Mg 2+ exceeded 1.0 × 10 3 . The mechanism extracting Pd(II) using [C 8 Y 3 Pr]Br was confirmed to be an anion-exchange reaction via Job’s method, spectral analysis (UV, FTIR), and DFT calculations. Alcohols and hydrazine hydrate were used as demulsifiers, and Pd nanoparticles were directly obtained from the microemulsion phase. The Pd nanoparticles were identified by TEM, XPS, and XRD analyses. The chemical structures of extracted species based on the microemulsion system and the mechanism of demulsification of alcohols were studied. Thus, an effective new process was developed in this study for the direct preparation of Pd nanoparticles from mixed metal solutions via solvent extraction.
研究领域:
化学
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材料科学
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纳米技术
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分析化学
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产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 57
·51757-51767
·
IF 3.289
Jian Liu,Liuchun Zheng,Yaowei Li,Michael Free,Mingzhu Yang
A cross-linked chitosan/montmorillonite (CCTS-M) membrane was prepared successfully with a glutaraldehyde cross-linker, and then was characterized by FTIR, XRD, SEM/EDX, TG/DTG and XPS. The materials were used for removing palladium(II) from aqueous solutions. The effect of variable parameters including initial pH, contact time, initial concentration, and temperature were investigated. The results showed that the maximum capacity of the membrane was 193 mg g−1 at pH 2. This article not only described the adsorption behavior but also suggested isotherms, the kinetics data were best modeled using pseudo-second-order model, and the Langmuir isotherm model could fit the experimental data well. The thermodynamic parameters ΔG° (<0) and ΔH° (>0) indicated that the adsorption was a spontaneous and endothermic process. FTIR and XPS techniques confirmed that the –NH3+, –NH2 and CN– functional groups in the CCTS-M membrane played prominent roles in the adsorption process. Our results revealed that the membrane could be a promising adsorbent for the recovery of palladium.
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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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）