CHINESE JOURNAL OF POLYMER SCIENCE
·
2017
·Vol. 35
·期 10
·1268-1275
·
IF 1.692
Peng Xin,Liu Tian-qi,Shang Cong,Jiao Chen,Wang Hui-liang
Simple preparation of stimuli-responsive hydrogels with good mechanical properties and mild stimuliresponsiveness is essential for their applications as smart soft robots. Mechanically strong Janus poly( N -isopropylacrylamide)/graphene oxide (PNIPAM/GO) nanocomposite hydrogels with stimuli-responsive bending behaviors are prepared through a simple one-step method by using molds made of a Teflon plate and a glass plate. Residual oxygen in the air bubbles on the Teflon plate surface affects the polymerization and hence the cross-linking density, leading to the different swelling/deswelling rates of the two sides of the gels. Therefore, the hydrogels exhibit bending/unbending behaviors upon heating/cooling in water. The incorporation of GO nanosheets dramatically enhances the mechanical properties of Janus hydrogels. Meanwhile, the photo-responsive property of the GO nanosheets also imparts the hydrogels with remotecontrollable deformation under IR irradiation. The application of the Janus PNIPAM/GO hydrogels as thermo-responsive grippers is demonstrated.
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APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Shengtao Gao,Feng Wei,Xinyao Zhu,Zihao Tai,Jun Qiao
Due to the low cost and steady physicochemical properties of carbon materials, zinc-ion hybrid capacitors (ZICs) composed of carbon cathode and Zn anode have aroused considerable attracts in recent years. However, the unsatisfactory capacity and electrochemical kinetics of carbonaceous cathode hinder its application in ZICs. Herein, a facile self-template thermal treatment method was proposed to prepare N, P co-doped hierarchical porous carbons (NP-HPCs). The electronically modified NP-HPC 3 has an ultrahigh ratio of active N species and abundant micropores, which is favorable for zinc ions adsorption. In addition, the three-dimensional cross-linked network with abundant mesoporous cavities synchronously boosts electrons/ions transfer kinetics. Ex-situ characterization shows that the introduction of N, P heteroatoms is helpful to improve the adsorption of zinc ions. Thanks to these favorable structural characteristics, the NP-HPC 3 displays an exceptional specific capacitance (275.0 F g −1 at 0.1 A g −1 ) and rate capability (182.0 F g −1 at 20 A g −1 ). More significantly, the NP-HPC 3 -based ZIC delivers a prominent energy density of 107.8 Wh kg −1 at a power density of 90.7 W kg −1 , a long cycle life (96.9 % capacitance retention after 10,000 cycles) together with an outstanding anti-self-discharge performance (0.001145 V h −1 @200 h). This study not only affords a feasible and environmental route to construct advanced heteroatom doped carbonaceous materials, but also explores the interrelation between zinc ions storage behavior and structural characteristics of carbon materials.
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ACS Catalysis
·
2024
·
IF 11.3
Li Jiang,Yiqian Yang,Lin Huang,Yan Zhou,Junwei An,Yuchun Zheng,Yiwei Chen,Yanhong Liu,Jianhui Huang,Ee Lui Ang,Suwen Zhao,Huimin Zhao,Rongzhen Liao,Yifeng Wei,Yan Zhang
The various isomers of hydroxyproline (HP) are widely distributed in nature, serving as key components of structural proteins, while their quaternized betaine derivatives function as osmoprotectants in many organisms. Aerobic bacteria degrade HPs through a variety of well-studied mechanisms. Recent studies show that certain anaerobic bacteria degrade HPs through distinct mechanisms, involving the O2-sensitive glycyl radical enzymes (GREs) t4L-HP dehydratase (HypD) and t4D-HP C–N lyase (HplG). Here, we report the discovery of two more GREs, N-methyl c4L-HP dehydratase (HpyG) and N-methyl c4D-HP dehydratase (HpzG), which catalyze radical-mediated dehydration of the two N-methyl-c4HP enantiomers, while also displaying significant activities toward their unmethylated substrates. Both GREs are associated with homologues of pyrroline-5-carboxylate reductase, which catalyze reduction of their products N-methyl-pyrroline-5-carboxylate to form N-methyl-proline. Crystal structures of HpyG and HpzG in complex with their substrates revealed active site architectures distinct from that of HypD and provided insights into the mechanism of enantioselective radical-mediated dehydration. Our research further expands the repertoire of diverse chemical mechanisms involved in the bacterial metabolism of highly prevalent HP isomers and derivatives in the anaerobic biosphere.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Yan Zhao,Luyi Yang,Yunxing Zuo,Zhibo Song,Fang Liu,Ke Li,Feng Pan
Employing conductive binders in silicon (Si) anode has been considered as a fundamental solution to the pulverization of Si particles. Therefore, it is still a great challenge to improve the charge transfer capability of the conductive binder. Herein, a copolymer (PFPQ-COONa) is synthesized, characterized, and electrochemically tested as conductive binder for Si anode. It is found that PFPQ-COONa exhibits not only excellent cycling stability, but also satisfactory rate performance with relatively high areal loading, which outperforms currently reported single-component conductive binders. The superior electrochemical performance can be attributed to the molecular-level contact between binder and Si particles and to the enhanced intrinsic conductivity of PFPQ-COONa at reductive potential. This method provides a fresh perspective to design and develop conductive binder for high-capacity battery anode.
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高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2017
·Vol. 28
·期 18
·1706018
·
IF 12.124
Shulin Zhao,Meng Li,Min Han,Dongdong Xu,Jing Yang,Yue Lin,Nai-En Shi,Yanan Lu,Rui Yang,Bitao Liu,Zhihui Dai,Jianchun Bao
Owing to their unique optical, electronic, and catalytic properties, metal nitrides nanostructures are widely used in optoelectronics, clean energy, and catalysis fields. Despite great progress has been achieved, synthesis of defect-rich (DR) bimetallic nitride nanocrystals or related nanohybrids remains a challenge, and their electrocatalytic application for oxygen evolution reaction (OER) has not been fully studied. Herein, the DR-Ni 3 FeN nanocrystals and N-doped graphene (N-G) nanohybrids (DR-Ni 3 FeN/N-G) are fabricated through temperature-programmed annealing and nitridation treatment of NiFe-layered double hydroxides/graphene oxide precursors by controlling annealing atmosphere. In the nanohybrids, the DR-Ni 3 FeN nanocrystals are anchored on N-G, and mainly show twin crystal defects besides ≈10% of stacking faults. Such nanohybrids can efficiently catalyze OER in alkaline media with a small overpotential (0.25 V) to attain the current density of 10 mA cm −2 and a high turnover frequency (0.46 s −1 ), superior to their counterparts (the nearly defect-free Ni 3 FeN/N-G), commercial IrO 2 , and the-state-of-art reported OER catalysts. Except for the superior activity, they show better durability than their counterparts yet. As revealed by microstructural, spectroscopic, and electrochemical analyses, the enhanced OER performance of DR-Ni 3 FeN/N-G nanohybrids originates from the abundant twin crystal defects in Ni 3 FeN active phase and the strong interplay between DR-Ni 3 FeN and N-G.
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ELECTROANALYSIS
·
2019
·Vol. 31
·期 4
·711-717
·
IF 2.691
Meiling Wang,Laijin Zhong,Mingzhu Cui,Weifeng Liu,Xuguang Liu
This study develops a novel approach to morphology-controlled N-doped porous carbons (NPC) derived from supramolecular crosslinked polypyrrole hydrogel (PPy-gel) with tetra-functional tetrakis(4-carboxyphenyl)porphyrin as dopant and cross-linker. Both optimized PPy-gel and NPC realize acetaminophen determination at nanomolar level, displaying record-low respective detection limits of 3.0 and 1.0 nM (S/N=3). The optimized NPC demonstrates necklace-like structure with more edge pyridinic N, revealing better electronic conductivity and higher electrochemically active surface area, and consequently higher sensitivity and selectivity. Even in the presence of three interferences (ascorbic acid, dopamine and uric acid), NPC based electrochemical sensor also shows the ultra-low detection limit (1.2 nM). The promising application potential of the sensor is proved by the high consistence between measurements in pharmaceutical sample and established acetaminophen standard curve. Moreover, the determination results of acetaminophen in human urine sample obtained by this sensor were in a good agreement with the reference values assayed by HPLC.
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Industrial Chemistry & Materials
·
2025
·
IF 11.9
Rongkai Cui,Minlei Yin,Xiaoyan Chen,Xiaoyu Lou,Chen Yang,Ting Qiu,Jie Chen
To achieve sub-angstrom separation of N-methylpyrrolidone and 1,5-dimethyl-2-pyrrolidone, cyclodextrin-derived carbon materials with distinct pore environments and surface functionalities were synthesized via hydrothermal carbonization and high-temperature pyrolysis. Three types of carbons were obtained: non-porous carbons rich in surface functionalities, carbons with both functionalities and microporous structures, and carbons with limited functionalities but diverse micropore environments. Systematic adsorption experiments, supported by density functional theory and molecular dynamics simulations, were conducted to establish the structure–performance relationships. The results demonstrate that surface functionalities alone are insufficient for separation, whereas pore confinement is the decisive factor. A 7.3 Å pore was identified as the optimal confinement space, providing the strongest thermodynamic interactions and the fastest diffusion kinetics, thereby enabling highly selective adsorption of 1,5-dimethyl-2-pyrrolidone from N-methylpyrrolidone. This work not only clarifies the pore formation mechanism of cyclodextrin-derived carbons but also highlights precise pore-size tuning as a paradigm for sub-angstrom molecular separation, offering theoretical guidance for the design of advanced adsorbent materials.
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高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Hanjun Zhang,Jing Chen,Yuxin Shi,Yaoyue Yang,Xiaole Jiang
Regulating the local microenvironment of metal centers represents an effective yet challenging approach to enhance the catalytic performance of atomically dispersed transition metal-nitrogen-carbon (M–N–C) catalysts towards the oxygen reduction reaction (ORR). Herein, atomically dispersed Cu–N–C catalysts featuring with adjustable carbon vacancies/defects concentrations (Cu–N–C V –X) are fabricated using a simple molten-salt-assisted pyrolysis strategy. The optimized catalyst (Cu–N–C V -1000) exhibits superior ORR catalytic performance with a half-wave potential ( E 1/2 ) of 0.89 V versus the reversible hydrogen electrode (RHE) and a turnover frequency ( TOF ) of 5.01 e site -1 s −1 at 0.85 V, surpassing Pt/C and most recently reported single-atom catalysts. Theoretical calculations confirm that defects adjacent to Cu–N 3 site downshift the d-band center of active sites, facilitating the desorption of *OH intermediate and thereby significantly enhancing the ORR kinetics. Consequently, the Cu–N–C V -1000-based zinc-air battery (ZAB) delivers a peak power density of 175.0 mW cm −2 along with a high discharge specific capacity of 819.4 mA g -1 Zn . This work confirms that the deliberate creation of suitable defects is an effective approach to optimize the intrinsic ORR activity of atomic M–N x sites, providing new insights into the rational design of high-performance catalysts for practical metal-air batteries.
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Journal of Materials Chemistry A
·
2025
·
IF 9.5
Yefei Wang,Fei Chang
The development of supported metal hydride catalysts with abundant active sites is a highly desirable yet challenging endeavor in ammonia synthesis. In this work, a lithium hydride (LiH)-loaded Fe/N-co-doped porous carbon (Fe-N-C) composite (LiH/Fe-N-C) was synthesized and demonstrated as an efficient catalyst for ammonia synthesis under mild conditions. The deposition of LiH onto Fe-N-C induced a partial reduction of the Fe-N moiety, resulting in the slight aggregation of isolated Fe single-atom sites into nanoparticles. Under reducing conditions (in the presence of H2), the coordinated nitrogen in Fe-N-C can be removed, forming nitrogen vacancies (VN), while surface iron hydride species (Fe-H) are generated through the interaction between LiH and Fe-N-C. The presence of Fe atoms adjacent to VN facilitates the adsorption and activation of dinitrogen, a process that is further supported by the replenishment of VN under reaction conditions. Notably, no lithium imide or amide species (Li2NH or LiNH2) — typically regarded as key intermediates in LiH-mediated ammonia synthesis, were observed on LiH/Fe-N-C, likely due to the fast hydrogenation step. Consequently, LiH/Fe-N-C achieves an ammonia production rate of 872 mmol·gFe-1·h-1, surpassing the performance of state-of-the-art Fe-based catalysts at 300 oC and 1 MPa. This study demonstrates that the synergistic catalysis of LiH, transition metals, and their adjacent nitrogen vacancies offers a promising pathway for efficient ammonia synthesis under mild conditions.
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Journal of Magnesium and Alloys
·
2025
·
IF 13.8
Cheng Lv,Qingjie He,Yongjin Zou,Ruoyang Zhang,Hanjie Wen,Jiayan Huang,Jing Zhi,Cuili Xiang,Lixian Sun,Yong Shen Chua
MgH 2 shows promise for solid-state hydrogen storage because of its high gravimetric capacity (7.6%) and ecofriendliness but cannot be easily commercialized because of its sluggish dehydrogenation/rehydrogenation kinetics and high thermodynamic stability. Herein, Ce/N–codoped TiO 2 (CN-T) synthesized using a solvothermal/calcination method was composited with MgH 2 to enhance its hydrogen storage performance. The composite with a CN-T loading of 7 wt% started releasing H 2 at 187.2 °C and released 6.45 wt.% H 2 in 180 s at 301 °C, which corresponded to nearly complete dehydrogenation. The residue could be rapidly rehydrogenated, with hydrogen contents of 3.24 and 5.45 wt% achieved in 1 min at 100 °C/20 bar H 2 and 5 min at 200 °C/20 bar H 2 , respectively. This performance enhancement was attributed to the combined effects of doped N, multivalent Ti, and Ce. The doped N weakened Mg–H bonds via charge transfer and modified the electronic state density of MgH 2 . Ti catalyzed H 2 dissociation/recombination through dynamic valence cycling and D-electron injection, and the introduction of Ce 3+ created O vacancies, which lowered the electron density of Mg–H bonds, generated strain fields for hydrogen release, provided diffusion pathways, and introduced bandgap states to strengthen electron–hydrogen coupling. Thus, this study paves the way for the commercialization of MgH 2 as a green high-capacity hydrogen carrier for diverse applications.
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Sustainable Energy & Fuels
·
2025
·
IF 4.1
Yongheng Xiong,Yang Yu,Huangang Shi,Jifa Qu,Wenyi Tan
Single atom Fe sites, doped in CN materials, exhibit outstanding electrochemical activity for CO2-to-CO conversion. The pyrolysis of ZIF8 is a controllable method for fabricating isolated single atom metal sites. In this study, we propose a new strategy to increase the ratio of Fe in ZIF8 precursors by synergistically replacing Zn2+ with Bi3+ and Fe3+. After precursor pyrolysis, the obtained Bi/Fe–N–C catalysts, consisting of Bi sites and pyrrole-type Fe–Nx sites, serve as efficient electrocatalysts for the CO2RR. The results show that the optimized catalyst loaded with 94.8 mg per kgCat Fe exhibits a high FECO of >90.1% over a wide potential range of −0.4 to −0.7 VRHE (98.2% at −0.5 VRHE). Insights into the electrochemical reaction mechanism show that this successful design of Bi/Fe–N–C catalysts can provide a stable catalytic site to form *COOH, thus achieving energy-efficient electrochemical CO2 reduction to CO.
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Chemistry-An Asian Journal
·
2025
·
IF 3.3
Boyu Jia,Li Ju,Fancang Meng,Huan Wu,Kexiang Li,Qingmin Ji
The chemical modification and self-assembly capability of fullerenes offer advantageous conditions for tailoring Fe/N-doped carbon-based catalysts. However, their strong π–π stacking tendency may partially restrict metal loading and the generation of active Fe species. Therefore, how to utilize the distinctive features of fullerenes to precisely regulate and optimize Fe–N active sites along with their local coordination environment remains challenging. In this work, water-soluble C 60 (wsC 60 ) was synthesized via a facile interfacial oxidation process. The presence of –OH on the C 60 cage may strengthen its binding affinity with Fe 3+ ion and effectively modulate the incorporation of Fe/N into the C 60 -derived carbon electrodes. By varying the wsC 60 /Fe 3+ mixing ratios followed by pyrolysis under NH 3 , we obtained Fe/N-doped carbons (FeN@wsC 60 -900) with distinct Fe/N-doping states, including FeN 4 , O–FeN 4 /Fe cluster, and FeN 4 /Fe cluster. The abundant –OH in wsC 60 also promoted the formation of a highly porous network, enhancing active site accessibility. The resultant FeN@wsC 60 -900 exhibited excellent oxygen reduction reaction (ORR) activity, outperforming both conventional C 60 -derived carbons and commercial Pt/C. Structural characterizations and density functional theory (DFT) simulations revealed that the O-coordinated Fe–N 4 with adjacent Fe cluster could optimize the coordinate geometry and adsorption energies of key ORR intermediates.
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