Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 22
·7419-7426
·
IF 6.4
Jia Yang,Mingxin Guo,Lanlan Feng,Jiajia Hao,Yaxin Guo,Zhipeng Li,Shuzheng Liu,Gang Qin,Gengzhi Sun,Qiang Chen
In the past few years, in situ polymerization of polyaniline (PANI) on a hydrogel polymer electrolyte (HPE) has been usually employed to fabricate flexible all-in-one supercapacitors, but many HPEs suffer from severe swelling during in situ deposition, resulting in poor mechanical properties or low electrochemical performances of supercapacitors. Here, a swelling resistant poly(2-acrylamide-2-methylpropanesulfonic acid)/polyacrylamide microgel reinforced (PAMPS/PAM MR) double network HPE with high ionic conductivity, good mechanical properties and excellent anti-freezing properties was prepared by two-step radical polymerization and followed by soaking the hydrogel in H3PO4 solution. After the deposition of PANI on the HPE, an all-in-one flexible supercapacitor could be successfully prepared. The PAMPS/PAM MR HPE showed swelling resistance during long-time deposition of PANI. The prepared supercapacitor exhibited excellent tensile strength (234 kPa), high specific capacitance (441 mF cm−2 at 1.0 mA cm−2), high-power density (762.30 μW cm−2) and high flexibility. The supercapacitor also demonstrated outstanding anti-freezing properties. We believe the swelling resistance of the HPE as well as the all-in-one supercapacitor can provide new insights into the next generation of supercapacitors with high electrochemical performances.
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POLYMER COMPOSITES
·
2023
·Vol. 44
·期 6
·3544-3554
·
IF 5.2
Jie Du,Shuiquan Li,Meichen Wang,Huihui Liu,Yan Wang,Ping Song,Zhi Wang
Reduced graphene oxide (rGO) exerts excellent performance in polymers, but suffers from poor dispersion. Here, the electrostatic interaction between the phenolic hydroxyl group of m-cresol and rGO was discovered for the first time, and benzoxazine with m-cresol containing rGO as the phenolic source were synthesized to achieve a more uniform dispersion of rGO in benzoxazine. The results show that the in situ synthesized rGO/benzoxazine system exhibited superior properties, including a lower curing reaction temperature (21°C relative reductions in curing temperature (225.7°C) for the system with 2 wt% rGO added in situ), higher dielectric constant ((8.69) relative improvement of 0.79), higher electromagnetic shielding value at 8.2–12.4 GHz ((7.45 dB) relative improvement of 0.75 dB), and higher thermal diffusivity at room temperature ((0.162 mm 2 /s) relative improvement of 26%). This study provides a method to homogeneously disperse rGO in benzoxazine without using of a solvent or any other treatment.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yingrui Tian,Dandan Zhi,Tian Li,Jinzhe Li,Jiatong Li,Zhengkang Xu,Wei Kang,Fanbin Meng
Graphene aerogels have attracted extensive attention in electromagnetic protection due to lightweight and efficient microwave absorbing properties, but until now the design of its shape and structure is still a research hotspot. Herein, reduced graphene aerogel microspheres (CSA-RGO AMs) with annual ring structure with regular interlayer spacing are synthesized by wet spinning-chemical reduction-lyophilization. Due to the special chiral helical structure and electromagnetic cross-polarization, the impedance matching and attenuation ability of microspheres to electromagnetic waves are enhanced. The CSA-RGO AMs at a low load of 4 wt% can achieve the minimum reflection loss (RL min ) of − 63 dB with a thickness of 3.6 mm, and the effective absorption bandwidth (EAB) reaches 7.04 GHz. On this basis, we further obtain polyaniline@reduced graphene oxide microspheres (PANi@RGO AMs) with the same chiral helical structure through in-situ doping polymerization of polyaniline. Heterogeneous interfaces bring the interface polarization and enhance the reflection and scattering of electromagnetic waves. And the corresponding RL min can reach − 48 dB when the thickness is only 2.8 mm, and the EAB remains 6.88 GHz. Therefore, the new strategy for constructing chiral structures proposed in this study provides a new idea for realizing high-performance electromagnetic wave absorption of graphene-based aerogel absorbers.
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Nature Sustainability
·
2023
·Vol. 6
·期 7
·816-826
·
IF 27.6
Lei Xin,Tang Qingyun,Zheng Yongping,Kidkhunthod Pinit,Zhou Xiaolong,Ji Bifa,Tang Yongbing
The electrocatalytic oxygen reduction and evolution of molecular oxygen, known as oxygen electrocatalysis, is one of the most important reactions that are central to a range of energy and environmental technologies. While the current best-performing electrocatalysts remain dominated by precious metals, carbon-based systems provide a compelling alternative owing to their intrinsic sustainability and practical applicability. Here we show a design guided by theoretical calculations that pushes the activity boundaries of carbon electrocatalysts to an unprecedented level. The rationale is that incorporating high-entropy heteroatoms could effectively minimize the local symmetry to destabilize the π-electron network of graphitic carbons and avoid too strong or too weak binding energies for intermediate species of the oxygen reduction reaction and the oxygen evolution reaction. Accordingly, our catalyst embeds five metal single atoms—Fe, Mn, Co, Ni and Cu—and two sources of N, and it exhibits superior bifunctional activities in an alkaline environment that exceed the oxygen reduction reaction and evolution reaction performance of commercial Pt/C and RuO 2 catalysts, respectively. Our work establishes electrocatalyst design principles that could open the door to sustainable solutions for critical green technologies such as fuel cells, batteries and water splitting.
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Small
·
2023
·Vol. 19
·期 26
·2301200
·
IF 13.3
Xiaojia Zhao,Qun Li,Pradip Pachfule,Zhiya Wang,Shiyin Liu,Weijian Wu,Mingxing Wu,Arne Thomas
Techniques beyond crystal engineering are critical for manufacturing covalent organic frameworks (COFs) and to explore them for advanced applications. However, COFs are normally obtained as insoluble, unmeltable, and thus nonprocessible microcrystalline powders. Therefore, it is a significant challenge to implement COFs into larger architectures and structural control on different length scales. Herein, a facile strategy is presented to prepare flexible COF nanofiber membranes by in-situ growth of COFs on polyacrylonitrile (PAN) nanofiber substrates via a reversible polycondensation-termination approach. The obtained PAN@COF nanofiber membranes with vertically aligned COF nanoplates combine a large functional surface with efficient mass transport, thus making it a promising adsorbent, for example, for water purification. The antibiotic pollutant ofloxacin (OFX) is removed from water with a superior absorption capacity of ≈236 mg g −1 and removal efficiency as high as 98%. The here presented in-situ growth of COFs on nanofiber membranes can be extended to various Schiff base-derived COF materials with different compositions, providing a highly efficient way to construct flexible COF-based membranes for several applications.
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ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Xinglin Jiang,Xiang Chu,Xiong Zhang,Yanting Xie,Tao Yang,Junfeng Huang,Wen Li,Weili Deng,Haitao Zhang,Weiqing Yang
The extraordinary pseudocapacitance of polyaniline (PANI) can be only realized in acid electrolytes with a limited potential window of 0.6∼0.8 V. As the potential further increases, PANI will suffer from the hydrolysis issue, leading to molecular-chain fracture and oxidative failure. In this work, we propose a strategy of surplus electron injection to stabilize the molecular chain of PANI at high cell potential. The surplus electron injection in 2D PANI is realized by exceeding the stable potential induced by an asymmetric supercapacitor structure design. As excessive charges are poured, supramolecular hydrogen bonds presented at 2D PANI capture them and generate additional redox reaction , which suppresses the damage of 2D PANI molecular structure and simultaneously strengthens its capacitive behavior. This effect is vividly demonstrated by the modulated electronic structure as indicated by shifting up the Fermi level , shifting down the work function and increasing the electrical conductivity. Consequently, high cell potential (1.2 V) 2D PANI supercapacitors with sulfuric acid electrolyte deliver a much longer cycling lifetime (76.8% vs. 45.1% after 10,000 cycles) and a much higher energy density (19.9 vs. 7.53 Wh kg ‒1 ) than that of low cell potential (0.8 V) 2D PANI counterpart. This work guides to a novel way to design high cell potential aqueous-solution supercapacitors.
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Small
·
2022
·Vol. 19
·期 8
·2206478
·
IF 15.153
Yuting He,Yufei Jia,Baozhu Yu,Yi Wang,Hongtao Li,Yongning Liu,Qiang Tan
Platinum group metal (PGM)-free M-N-C catalysts have exhibited dramatic electrocatalytic performance and are considered the most promising candidate of the Pt catalysts in oxygen reduction reaction (ORR). However, the electrocatalytic performance of the M-N-C catalysts is still limited by their inferior intrinsic activity and finite active site density. Regulating the coordination environment and increasing the pore structure of the catalyst is an effective strategy to enhance the electrocatalytic performance of the M-N-C catalysts. In this work, the coordination environment and pore structure exquisitely regulated Fe-N-C catalyst exhibit excellent ORR activity and durability. With the enhanced intrinsic activity and increased active site density, the optimized Fe-N/S-C catalyst shows impressive ORR activity ( E 1/2 = 0.904 V vs reversible hydrogen electrode (RHE)) and superior long-term durability in an alkaline medium. As the advanced physical characterization and theoretical chemistry methods illustrate, the S-modified Fe-N x (Fe-N 3 /S-C) moiety is confirmed as the improved active center for ORR, and the increased active site density further improved ORR efficiency. Based on the Fe-N/S-C cathode, a Zn-air battery is fabricated and shows superior power density (315.4 mW cm −2 ) and long-term discharge stability at 20 mA cm −2 . This work would open a new perspective to design atomically dispersed iron-metal site catalysts for advanced electro-catalysis.
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JOURNAL OF POLYMER SCIENCE
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2022
·Vol. 61
·期 6
·491-502
·
IF 3.046
Lidong Cao,Xingzhong Fang,Guofei Chen
High imidization temperature of polyimides (PIs) brings great restriction to the applications in electronic industry. In this study, N,N ′-carbonyldiimidazole (CDI), a novel low-temperature imidization accelerator with the unique dual function of catalyst and dehydrating agent, was researched to solve this problem. PIs synthesized from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 4,4′-oxydianiline were researched as the main object on method A and method B, two preparation methods of PIs, by introduction of CDI, which was found that the PIs prepared by method A achieved complete imidization and basically had no residual CDI and N,N -Dimethylacetamide at 180 °C under vacuum, while the completely imidized PIs prepared by method B were also obtained at 40 °C. Even prepared at low temperature, the PI films with adding CDI both showed satisfactory thermal and mechanical properties, especially in reducing coefficient of thermal expansion. In addition, the universality of the reaction between CDI and poly(amic acid) were also verified by other soluble PI systems. All these results prove the superior performance of CDI in lowering imidization temperature, showing great potentials in low-temperature cured PIs. Graphical
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WATER RESEARCH
·
2022
·
IF 13.4
Chaozhi Kuang,Guoshen Zeng,Yangjian Zhou,Yaoyao Wu,Dexuan Li,Yingfei Wang,Chuanhao Li
Conventional electrocatalytic degradation of pollutants involves either cathodic reduction or anodic oxidation process, which caused the low energy utilization efficiency. In this study, we successfully couple the anodic activation of sulfates with the cathodic H 2 O 2 production/activation to boost the generation of sulfate radical (SO 4 ·− ) and hydroxyl radical (·OH) for the efficient degradation of emerging contaminants. The electrocatalysis reactor is composed of a modified-graphite-felt (GF) cathode, in-situ prepared by the carbonization of polyaniline (PANI) electrodeposited on a GF substrate, and a boron-doped diamond (BDD) anode. In the presence of sulfates, the electrocatalysis system shows superior activities towards the degradation of pharmaceutical and personal care products (PPCPs), with the optimal performance of completely degrading the representative pollutant carbamazepine (CBZ, 0.2 mg L −1 ) within 150 s. Radicals quenching experiments indicated that ·OH and SO 4 ·− act as the main reactive oxygen species for CBZ decomposition. Results from the electron paramagnetic resonance (EPR) and chronoamperometry studies verified that the sulfate ions were oxidized to SO 4 ·− radicals at the anode, while the dissolve oxygen molecules were reduced to H 2 O 2 molecules which were further activated to produce ·OH radicals at the cathode. It was also found that during the catalytic reactions SO 4 ·− radicals could spontaneously convert into peroxydisulfate (PDS) which were subsequently reduced back to SO 4 ·− at the cathodes. The quasi-steady-state concentrations of ·OH and SO 4 ·− were estimated to be 0.51×10 −12 M and 0.56×10 −12 M, respectively. This study provides insight into the synergistic generation of ·OH/SO 4 ·− from the integrated electrochemical anode oxidation of sulfate and cathode reduction of dissolved oxygen, which indicates a potential practical approach to efficiently degrade the emerging organic water contaminants.
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ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
Kai Niu,Pengcheng Sun,Jiping Chen,Xianbo Lu
Due to the fascinating properties such as high porosity, large surface areas, and tunable chemical components, metal–organic frameworks (MOFs) have emerged in many fields including catalysis, energy storage, and gas separation. However, the intrinsic electrical insulation of MOFs severely restricts their application in electrochemistry. Here, we synthesize a series of 2D conductive MOFs (cMOFs) through tuning the structure with atomic precision using simple hydrothermal methods. Various electroactive probes are used to reveal the structure–property relationships in 2D cMOFs. Then, we demonstrate the first exploration and implementation of 2D cMOFs toward the construction of electrochemical biosensors. In particular, the biosensor based on Cu3(tetrahydroxy-1,4-quinone)2 [Cu3(THQ)2] displays a remarkably improved electrocatalytic performance at a much lower potential. The mechanism study reveals the essential role of charge-transfer interactions between the dense catalytic sites of Cu3(THQ)2 and analytes. Furthermore, the Cu3(THQ)2-based biosensor demonstrates robust anti-interference capability, good stability, fast response speed, and an ultralow detection limit for paraoxon. These promising results indicate the great potential of cMOFs in biomedical, food safety, and environmental sensing applications.
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Nanoscale Advances
·
2022
·Vol. 5
·期 1
·133-141
·
IF 5.598
Shanshan Wei,Shiyong Li,Haolin Xiao,Feijun Zhao,Jianming Zhu,Zhencheng Chen,Liangli Cao
Gastric cancer (GC) is a common malignant tumour of the digestive tract with a high mortality rate worldwide. However, many patients delay treatment due to the avoidance of the costly and painful procedure of gastroscopy. Therefore, an early convenient screening method is essential to improve the survival rate of GC patients. To address this issue, we constructed an electrochemical immunosensor supported by rhombohedral Cu3Pt and MoS2 nanoflowers (MoS2 NFs) for rapid, painless and quantitative detection of the GC biomarker in vitro. Here, pepsinogen I was employed as a model protein biomarker to analyse the performance of the immunosensor. The rhombohedral dodecahedral Cu3Pt nanoparticles decorated with MoS2-NFs were further functionalized; this allowed the constructed sensor to possess more nano- or micro-structures, thereby improving the detection sensitivity. In specific applications, the corresponding bioactive molecules can be flexibly captured. Under optimal conditions, the immunoassay showed a wide linear range from 500 pg mL−1 to 400 ng mL−1 and a low detection limit of 167 pg mL−1 (S/N = 3). This covers the critical value of 70 ng mL−1, and the results obtained from the analysis of human serum samples were on par with those from the enzyme immunoassay, suggesting significant potential for this new method in daily diagnosis.
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Molecular Catalysis
·
2022
·
IF 5.089
Zichen Zhang,Donglin Yang,Jiaqiang Wang,Chaoting Deng,Hengjun Gai,Meng Xiao,Tingting Huang,Quanhong Zhu,Hongbing Song
Ionic liquids (ILs) are unique substances with unique ionic sites. They are regarded as one of the most promising green solvents and catalysts in the 21st century. In this work, the synthesis of imidazolium-based ILs as metal-free catalysts by molecular design is reported for the first time. By using the ILs as precursors, hyper-crosslinked poly(ionic liquid) (HCPIL) was synthesized by Friedel–Crafts alkylation reaction. These metal-free catalysts can effectively activate ethanolamine for the hydrogenation of nitrobenzene, and they have definite active sites. As the synthesized HCPIL-Cl has a rich porous structure and IL structural units, it could maintain the catalytic activity of ILs and recover them via efficient facile filtration and washing. Density functional theory (DFT) calculation suggested that the imidazolium structure is essential to ethanolamine activation. The calculated results of DFT agree well with the experimental results. The hydrogenation of nitrobenzene has many intermediates whose selectivity can be regulated by different gas atmosphere or alkaline environments. This work provides a promising method for the design of metal-free catalysts.
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