POLYMER BULLETIN
·
2012
·Vol. 70
·期 2
·467-478
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IF 1.532
Yan Manqing,Yang Hongjun,Xing Xinming
Poly(ε-caprolactone- co -ethylene carbonate- co -ethylene oxide) (CL- co -EC- co -EO) copolymer was synthesized via ring-opening copolymerization of ε-caprolactone (CL) and 1,3-dioxolan-2-one with a metal-free phosphazene catalyst ( t -BuP 4 ). The monomer conversion and molecular weight in CL- co -EC- co -EO copolymer were characterized by nuclear magnetic resonance and gel permeation chromatography, respectively. Moreover crystallization behavior of CL- co -EC- co -EO copolymer was investigated by differential scanning calorimeter and wide-angle X-ray diffraction. The enzymatic degradation of the copolymer has been investigated by quartz crystal microbalance with dissipation. Our studies demonstrate that as PCL content in the copolymer decreases, the degree of crystallinity and crystal size decrease, while the enzymatic degradation rate increases. The copolymer exhibits layer-by-layer degradation.
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CHEMICAL ENGINEERING JOURNAL
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2025
·
IF 13.2
Jun Lu,Mingyue Xia,Jing Liang,Lie Zou,Xiaolong Liang,Yan Gao,Fei Li,Junfeng Gao,Jinxuan Liu
Cu 2 Y 2 O 5 with asymmetric atomic distance distribution was investigated for the first time in CO 2 electroreduction reaction (CO 2 RR). The high electrophilicity of Y not only regulates the electronic structure of Cu, but also acts as an electron dock to attract CO*, promoting its toward Y and effectively protecting the stability of Cu 2+ during the reduction process. In a Flow cell, CYO-850 achieves an exceptionally high selectivity of 70 % for ethylene, accompanied by a high partial current density of 200 mA cm −2 . In-situ infrared spectroscopy and density functional theory results indicate that interaction between Cu and Y promotes the dimerization of *OCCO intermediates and directs the CO 2 reduction pathway towards ethylene. This is the first report on the use of Y element in the field of CO 2 reduction.
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ChemPlusChem
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2025
·
IF 2.8
Wen Feng,Congyue Sun,Xiaojin Li,Xiliang Luo,Liu Wenqi
The exploitation of an efficient and stable oxygen reduction reaction (ORR) catalyst plays a crucial role in the slow kinetics of the cathode in proton exchange membrane fuel cells (PEMFC). In this study, a catalyst loaded with PtCo alloys on Co and N co-doped carbon nanotubes (PtCoNC) was synthesized for oxygen reduction reaction, which has high activity and stability. The carbon nanotube structure provides efficient transport channels for reactant exchange and product transport, as well as provides a wealth of triple-phase sites, that improves the utilization of Pt. Further, the PtCoNC catalyst exhibits robust metal-support interactions, which can be attributed to the anchoring of the Co-Nx sites to Pt. Theoretical calculations indicating an increase in binding energy and a reduction in layer spacing provide conclusive verification of the presence of augmented interactions between PtCo nanoparticles and the support. As a result, the low Pt-loaded (0.025 mg cm-2) PtCoNC catalyst demonstrates superior ORR activity to that of commercial Pt/C with an impressive half-wave potential of 0.893 V in 0.1 M HClO4 solution. At 0.9 V, its mass activity and specific activity are 3 and 2.6 times that of commercial Pt/C, respectively. It also shows better stability in acidic environment.
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PubMed
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Surfaces and Interfaces
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2025
·
IF 6.3
Jiangang Kang,Haihong Zhang,Yuehui He,Liang Wu,Hengdi Ye,Jinchao Wei
The novel Ni-Si intermetallic compounds are fabricated by elemental powder metallurgy. This study explores the synthesis of a series of catalysts (Ni-Si-M, M=Co, Fe, Mn) by alloying to augment the low-temperature efficiency of CO oxidation using Ni-Si intermetallic compounds. It is found the low-temperature catalytic activity of Ni-Si-Co, Ni-Si-Fe, and Ni-Si-Mn catalysts are significantly enhanced compared to the original Ni-Si. The catalytic activity among the catalysts ranks as follows: Ni-Si-Co > Ni-Si-Fe > Ni-Si-Mn > Ni-Si. The apparent activation energy (Ea) for Ni-Si-Co was the lowest at 57.3 kJ/mol, suggesting its efficient catalytic oxidation of CO. Additionally, the addition of Co, Fe and Mn elements actually promotes the generation of Ni 2+ as the CO adsorption site in the original Ni-Si. The addition of Co element also leads to the formation of Co 2+ as the adsorption site of O 2 in the process of CO oxidation reaction. The synergistic adsorption of Ni 2+ and Co 2+ to CO and O 2 promotes the CO oxidation reaction. Additionally, the catalysts demonstrate robust long-term stability in atmospheres containing H 2 O and SO 2 , with CO conversion initially suppressed but subsequently recovering and stabilizing at over 90%. This investigation offers novel insights into enhancing the low-temperature activity and stability of catalysts.
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Materials Research Express
·
2020
·Vol. 7
·期 2
·025010
·
IF 1.929
Hong-Wei He,Xin-Yuan Li,Zhao-Jun Zhao,Xu Yan
Polymer template method is a general and facile to fabricate nano-structural matters. Some amphiphilic polymers or co-polymers were used as templates to synthesize nano-silica. In this contribution, polymethacrylate (PMMA) employed was a commercial hydrophobic acrylate polymer and grafted with a strong hydrophilic polyethyleneimine (PEI, a densely amino-groups polymer) via aminolysis reaction, which was monitored and identified by means of FT-IR. The aminolysis reaction was optimized and the suitable reaction time was 12 h at 110 °C. The obtained copolymer, PMMA-co-PEI was applied as a template to prepare nano-silica spheres that was characterized by a scanning electron microscope (SEM). When the dosage was 1 wt% of purified PMMA-co-PEI, the resultant nano-silica had uniform particle size, and average diameter of 311 nm. When the dosage of PMMA-co-PEI was increased to 2 wt% or 4 wt%, the resultant particles became bigger and inclined to aggregate. Nano-silica afforded by this template method will be a promising material in application of catalysis, energy, biology and chromatographic analysis and the copolymer of PMMA-co-PEI will be a template for producing metal oxide nano-spheres.
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Molecular Catalysis
·
2020
·
IF 3.687
Fanfan Yue,Ao Hu,Xinhuan Lu,Chenlong Wang,Haijun Pan,Haifu Zhang,Lu Yang,Qinghua Xia,Dan Zhou,Yongde Xia
Benzimidazole and metal cobalt salts were employed in the synthesis of Co-ZIF-9 by solvothermal crystallization. Highly active catalysts for selective hydrogenation of carbonyl compounds were developed. The optimal nanocatalyst Co-ZIF-350 manifested remarkable activity and selectivity for the hydrogenation of cyclohexanone under mild conditions. Catalytic conversion of cyclohexanone reached the highest over the catalyst of Co-ZIF-9-pyrolyzed at 350 °C for 2 h, in which the conversion of cyclohexanone was 100 % and the selectivity of cyclohexanol was ＞99 % at 50 °C. A wide scope of ketones/aromatic aldehydes could be selectively reduced to the corresponding alcohols with high yields. Importantly, the nanocatalyst Co-ZIF-350 presented good tolerance of substrates with various functional groups under mild conditions.
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CHEMOSPHERE
·
2022
·
IF 8.943
Hanlin Wang,Haibo Liu,Xuehua Zou,Fuwei Sun,Luyao Wang,Jingchao Hu,Dong Chen,Meng Liu,Jianfei Shen,Tianhu Chen
In this work, the effect of Co substitution in the Fe 1-x S (CSP) on the activation of H 2 O 2 to degrade tetracycline (TC) is investigated. A series of CSP samples with different Co content are synthesized via a high-temperature sulfidation method and characterized by XRD , XPS , SEM, and electrochemical analysis . The result showed that low Co content (≤1%) promotes the catalytic activity of Fe 1-x S, while excessive Co (1%﹤x ≤ 3%) inhibits its catalytic activity. The investigation of Behnajady-Modirshahla-Ghanbery kinetic model (BMG) showed that the maximum initial degradation rate of TC over 1.0% CSP/H 2 O 2 was 1.6 times than that of in CSP/H 2 O 2 system. The Box-Behnken with Response Surface Methodology was employed to verify optimum condition for TC degradation. The quenching experiments and ESR determined that ·OH, ·O 2 − and 1 O 2 were involved in TC degradation with the treatment of 1.0% CSP/H 2 O 2 system. Electrochemical analysis, ·OH quantification, and metal ion concentrations measure reveal that Co substitution accelerates electron transfer efficiency and Fe 2+ regeneration. Furthermore, nine intermediates are identified and the possible degradation pathway of TC is proposed. The unique effect of Co provides novel insight and efficient strategies for improving the reactivity of iron sulfide.
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Materials Today Chemistry
·
2025
·
IF 6.7
Xiaotong Song,Junyuan Zhang,Weiqi Li,Huanying Li,Zhiguo Li,Xiaolong Xu,Changyu Liu,Jianbo Jia
Metal-organic framework (MOF)-derived carbon nanocomposites have been widely applied in electrocatalytic fields due to their simple synthesis, excellent conductivity, and high catalytic activity. In this study, ZIF-67 and MIL-101(Fe) were synthesized via liquid-phase precipitation and solvent thermal methods, respectively. Then, the two kinds of MOFs were ground and calcined with melamine to prepare flower-like carbon nanocomposites. Under the optimal conditions, the oxygen reduction reaction (ORR) onset potential (E onset = 1.019 V vs. reversible hydrogen electrode, RHE) and half-wave potential (E 1/2 = 0.866 V) of this prepared composite are both higher than those of commercial Pt/C catalyst (E onset = 0.971 V, E 1/2 = 0.838 V). The prepared nanocomposite exhibits a lower oxygen evolution reaction (OER) overpotential (η = 338 mV at 10 mA cm −2 ) than RuO 2 (η = 372 mV), demonstrating superior catalytic performance. The prepared nanocomposite achieves simultaneous enhancement in both ORR and OER bifunctional catalytic performances. The power density of a zinc-air battery (ZAB) assembled with the optimal nanocomposite was 2.65 times higher than that of the Pt/C + RuO 2 system. This study establishes a fundamental framework for the rational design of high-performance ORR/OER bifunctional catalysts, while pioneering new avenues for ZAB technology commercialization.
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Journal of Physical Chemistry C
·
2019
·
IF 4.309
Xueyang Song,Li Huang,Wenxue He,Chengyong Liu,Fengchun Hu,Yong Jiang,Zhihu Sun,Shiqiang Wei
Electronic metal–support interactions (EMSIs) have opened a new way to tailor the electronic and catalytic properties of supported catalysts. Herein, we demonstrate the EMSIs between Pt nanoparticles and Co(OH)2 flakes grown on SiO2 and show its beneficial effect on enhancing the CO oxidation activity. The EMSI characteristics of the Pt–Co(OH)2/SiO2 catalyst are identified by in situ X-ray absorption fine structure (XAFS) spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and transmission electron microscopy. Quantitative XAFS analysis reveals the presence of metallic-like Pt–Co bonds. The formation of Pt–Co intermetallic bonds allows for electron donation form Co to Pt, leading to the negative charging of the Pt atoms as evidenced by reduced Pt 2p-to-5d electron-transition intensity detected by XAFS spectroscopy and the emergence of a CO adsorption band at 2063 cm–1 in DRIFTS. The significance of EMSIs is manifested by comparing the CO oxidation activity over the Pt–Co(OH)2/SiO2 and Pt/SiO2 catalysts with similar Pt loadings. Pt–Co(OH)2/SiO2 is superior to Pt/SiO2 in both the apparent activation energy (19 vs 64 kJ/mol) and the turnover frequency (0.03 vs 0.003 s–1 at 37 °C). The enhanced activity is attributed to the negative charging of Pt, which downshifts the d-band center and reduces the CO adsorption strength.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2023
·
IF 4.2
Jiahui Xu,Jia-qi Bai,Wenjie Si,Yunhai Zhang,Jiazhao Tan,Mengdie Cai,Qin Cheng,Song Sun
Non-noble metals have attracted worldwide attention for the catalytic hydrogenation of halonitrobenzene due to their high activity, low price, and abundance on Earth. However, the construction of effective and stable non-noble-metal catalysts for the selective hydrogenation of halonitrobenzene to haloaniline by a simple method remains challenging. Herein, we report a facile one-pot method for the synthesis of N,S-co-doped mesoporous carbon-supported non-noble-metal catalysts through carbonization of a mixture of metallic precursors and 2-aminothiazole in molten ZnCl2. The prepared Co-NSPC catalyst showed excellent activity and selectivity with a turnover frequency of 84.4 h–1 in the hydrogenation of p-chloronitrobenzene to p-chloroaniline. Furthermore, Co–Nx was found to be the main active site for this reaction on the basis of characterization and experimental data, and the introduction of S promoted the formation of Co–Nx sites. Moreover, the Co-NSPC-800 catalyst can be reused at least four times and applied to the hydrogenation of 10 kinds of halogenated nitrobenzenes with excellent selectivity.
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FUEL
·
2024
·
IF 6.7
Anqi Li,Xiaoyu Qian,Mengyan Han,Zhichun Li,Xiaobo He,Guofeng Wang
Electrochemical catalytic water splitting is considered as a promising technique for green hydrogen production, and highly active catalysts toward cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) are required, especially bifunctional ones. In this work, the bifunctional catalysts with Co-CoO x @N, O co-doped carbon (NOC) hybrid nanostructures have been prepared via pyrolysis of ZIF-Co with assistance of a small amount of KNO 3 . KNO 3 plays important roles in tuning the inner and the outer structures of Co-CoO x @NOC hybrid nanostructures. The proposed S Ov , which is defined as the content of oxygen vacancy (O v ) per unit surface area of the inner Co-CoO x nanoparticle, and charge transfer resistance ( R ct ) are used as the descriptors of the inner structures, while hydrophilicity (or contact angle) is applied as the main feature of the outer structures. S Ov , R ct and hydrophilicity are well tuned by the fed mass of KNO 3 , and a moderate fed mass is the key to balancing S Ov , R ct and hydrophilicity and further is beneficial to accelerating specific and intrinsic activity for both HER and OER . Thus, the bifunctional HER/OER specific and intrinsic activity is peaked by Co-CoO x @NOC-0.025KNO 3 with a moderate fed mass of KNO 3 of 0.025 g, such as j s-250-HER of 539.22 μA cm -2 BET and j s-350-OER of 129.83 μA cm -2 BET at the HER and OER overpotentials of 250 and 350 mV, respectively, also corresponding to high turnover frequencies of 6.653 and 0.801 s −1 , respectively. The optimal catalyst also has high apparent activity, such as achieving high HER and OER current densities of 500 mA cm −2 , only requiring low overpotentials of 273.1 and 382 mV, respectively. It promotes overall water splitting with a high current density of 500 mA cm −2 at a cell voltage of ∼ 1.63 V, showing the high HER and OER Faradaic efficiencies of ∼ 98.2 and ∼ 98.0 %, respectively.
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FUEL
·
2025
·
IF 7.5
Yongpeng Ma,Jianghui Du,Yifei Wu,Haobing Yan,Ruiqi Liu,Xiaojing Zhang,Hongzhong Zhang,Liming Zhou,Wenjun Huang
Among the diverse pollutants emitted from coal-fired and non-ferrous metal smelting flue gas, Hg 0 and CO have emerged as globally concerning environmental pollutants. However, the simultaneous abatement of multiple pollutants remains a critical challenge to be addressed. In this study, cobalt nanoclusters (Co NCs) were anchored on the terminal oxygen of Ti-O on Ti 3 C 2 MXene and formed asymmetric oxygen vacancies Co-Ov-Ti via a one-step hydrothermal method, yielding Co NCs/Ti 3 C 2 MXene with a morphology of hierarchical nanosheet-assembled spheres for Hg 0 and CO catalytic oxidation. Co NCs/Ti 3 C 2 MXene exhibited excellent 44 % and 52 % of Hg 0 and CO simultaneous removal efficiency at the optimal temperature of 250 °C, respectively. DFT calculations combined with energy barrier modeling were employed to investigate the reaction pathways and energy variations during the catalytic oxidation of Hg 0 and CO. Specifically, Hg 0 oxidation follows the Eley-Rideal mechanism, with a rate-determining energy barrier of 2.11 eV, while CO oxidation adheres to the Langmuir-Hinshelwood mechanism, featuring a rate-determining barrier of 0.17 eV. In the co-catalytic oxidation process, competitive adsorption between Hg 0 and CO was observed, primarily manifested as competition for Ov on the catalyst surface. This study provides a novel strategy for the synergistic control of multi-pollutants in industrial flue gas.
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