Nanoscale
·
2020
·Vol. 12
·期 26
·14259-14266
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IF 6.895
Yi Guan,Nan Li,Yongliang Li,Lingna Sun,Yuan Gao,Qianling Zhang,Chuanxin He,Jianhong Liu,Xiangzhong Ren
Bottom-up construction of transition copper–nitrogen–carbon (Cu–N–C) electrocatalysts with high-performance and long-term durability for the oxygen reduction reaction (ORR) still remains a great challenge. Herein, we propose a temperature-controlled synthesis strategy with confinement effect for fabrication of a novel two-dimensional dual-metal (Cu/Zn) zeolitic imidazolate framework material, which presents an ultrathin nanosheet morphology after high-temperature thermal treatment (denoted as Cu–N-UNS). By controlling the reaction temperature as well as regulating the ratio of metal ions and taking advantages of the confinement effect of surfactants, the rationally designed ultra-thin carbon layer not only prevents aggregation of transition Cu particles and avoids direct contact with reactants and electrolyte solutions to enhance the durability of electrocatalysts, but also shortens the electronic transmission path between the active transition metal species and carbon surface. Therefore, the electrocatalyst exhibits excellent electrocatalytic performance for the ORR (E1/2 ≈ 0.898 V), which is superior to those of state-of-the-art benchmark noble-metal electrocatalysts. Moreover, the even distribution of Cu–N–C and existence of N–Cu2+–Cu0 active sites make a great contribution to the electrocatalyst activity. Notably, the Cu–N-UNS used as air electrodes for Zn–air batteries also exhibits a high peak power density of ≈134.7 mW cm−2 at a current density of ≈231.9 mA cm−2 with remarkable durability.
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JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY
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2019
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IF 4.067
Sai Kumar Tammina,Yang Wan,Yanyan Li,Yaling Yang
A simple and one-step microwave digestion method was utilized to synthesize the highly photoluminescent glucosamine derived nitrogen and zinc doped carbon dots (N, Zn-CDs) with a bluish-green luminescence property. The synthesized N, Zn-CDs inherited a good photoluminescence property with a quantum yield of 74% and which were characterized by XPS , XRD , TEM , FT-IR, UV–Vis, and fluorescence spectrometry . More importantly, N, Zn-CDs served as a fluorescence sensor for the detection of Fe 3+ ions, under optimal conditions, a good linear relationship was established in the concentration range of 0.25–125 μM. Also, the experimental results showed the detection limit of N, Zn-CDs against Fe 3+ was 0.15 μM, this could be a promising assay for sensing Fe 3+ ions. Also, the role of zinc doping was explored by conducting the detection under similar experimental conditions in the absence of zinc, and reports revealed that the reason for high photoluminescence was due to the zinc doping. Along with the sensing application, our group had investigated the bactericidal property of synthesized N, Zn-CDs against gram-negative ( Escherichia coli ), and gram-positive pathogens ( Staphylococcus aureus ). N, Zn-CDs displayed good bactericidal activity against both pathogens under light conditions, but Escherichia coli , even under the dark condition proved its activity. Besides, the morphology of both the strains was displayed before and after the treatment via a scanning electron microscopic images. Also, a plausible mechanism for bactericidal activity was also explained. The reported synthesis method could provide a novel approach for the design of high photoluminescent N, Zn–CDs with good sensing and bactericidal property towards Fe 3+ ions, gram-negative and positive bacterial strains .
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Nanoscale
·
2019
·Vol. 12
·期 2
·973-982
·
IF 6.97
Jia-Jun Cai,Qing-Yan Zhou,Bing Liu,Xiao-Fei Gong,Yun-Long Zhang,Kokswee Goh,Da-Ming Gu,Lei Zhao,Xu-Lei Sui,Zhen-Bo Wang
Non-noble metal materials are regarded as the most promising catalysts for the oxygen reduction reaction (ORR) to overcome the inherent defects of Pt-based catalysts, like high cost, limited availability and insufficient stability. Here, we fabricate sandwich-like Co encapsulated nitrogen doped carbon polyhedron/graphene (s-Co@NCP/rGO) via a facile and scalable strategy by loading Co-based zeolitic imidazolate framework (ZIF-67) and graphene oxide (GO) layers individually on a polyurethane (PU) sponge template. The 3D sandwich structure is maintained with the assistance of the sponge template, which promotes the uniform dispersion of ZIF-67-derived Co embedded nitrogen doped carbon polyhedra (Co@NCP) and prevents the graphene plates from agglomerating during the annealing process. The final product demonstrates considerable catalytic performance for the ORR with a half-wave potential of 0.85 V, preferable stability and increased poisoning tolerance by comparison to 20 wt% Pt/C, which stems from the 3D sandwich-like structure, N/Co-doping effect, large accessible surface area and hierarchical porous structures. The excellent ORR performance of the catalysts means that they can be utilised in a Zn–air battery as cathode catalysts. During such a demonstration, s-Co@NCP/rGO shows a high open-circuit voltage of 1.466 V, remarkable long-term durability and an outstanding peak power density of 186 mV cm−2, which shows its high potential as a prospective alternative for widespread practical application in the field of non-noble metal ORR catalysts.
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ACS Omega
·
2023
·
IF 4.1
Fei Nie,Ru Yu,Lina Wang,Liping Jiang,Qi Wu,Wenhua Xu,Xiaolong Fu
Four metal–organic frameworks (MOFs) were designed and prepared through a mixed-ligand strategy by controlling the combination of various dicarboxylic acid ligands with invariant center metal and o-phenanthroline heterocyclic ligand. The regulatory effects of ligand electronic band and crystal structure on the electrochemiluminescence (ECL) characteristics of MOFs were verified by experimental results and density functional theory (DFT) calculations. The flexible chain structure of MOF-2 promotes electron transfer between MOF electroactive free radicals and the co-reactant, making it show outstanding ECL characteristics among all of the four MOFs with the luminescence quantum efficiency 8.37 times that of tris(bipyridine)-ruthenium(II) ([Ru(bpy)3]2+). Meanwhile, a new ECL mechanism for MOF luminescent crystal materials with reactive oxygen species in solvents as a co-reactant in the aqueous aerobic environment has been proposed. MOF-2 was selected to construct an ECL sensor for the determination of glucose in human urine samples. This study provides a useful idea for the development and design of new luminescent molecular crystal materials.
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ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Ran Li,Deliang Zhang,Huamao Chen,Shaozhen Wang,Yunyun Ling,Caihong Fang
Developing high-performance and low-cost electrocatalysts for the oxygen evolution reaction (OER) and urea oxidation reaction (UOR) is essential for hydrogen production. Herein, we prepared Zn,S-incorporated Fe,Co layered double hydroxide (ZnCoFeS–LDH) nanosheets on nickel foam via a two-step hydrothermal reaction. The attractive two-dimensional (2D) nanosheet morphology with ultrathin thickness offers abundant active sites, promotes the adsorption and desorption of intermediates on the surface, and also facilitates mass transportation. The electronic structure of ZnCoFeS–LDH was modified, which thus improves their conductivity, offers high-valence iron ions (Fe3+), and therefore intrinsically enhances their electrocatalytic properties. In particular, the constructed crystalline/amorphous interfaces benefit electron transfer between different phases. As a proof of concept, we examined the electrocatalytic performances of ZnCoFeS–LDH nanostructures to both the OER and UOR. As a result, the ZnCoFeS–LDH nanosheets exhibit excellent catalytic OER activity, with low overpotentials of 202, 217, 238, and 261 mV to achieve current densities of 10, 20, 50, and 100 mA cm–2, respectively, which are remarkably enhanced in comparison with that of commercial RuO2. Furthermore, they also demonstrate outstanding durability after long-term (48 h) and cycling (5000 cycles) measurements. Moreover, the ZnCoFeS–LDH nanosheets also possess superior UOR activity. The potentials were measured to be as low as 1.313, 1.334, 1.366, and 1.398 V to reach current densities of 10, 20, 50, and 100 mA cm–2, respectively, with high long-term stability after 20 h.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Lanyue Zhang,Hongquan Jiang,Chunmei Wang,Kai Yu,Jinghua Lv,Chunxiao Wang,Baibin Zhou
Enhancing performance through the combination of polyoxometalates (POMs) clusters with metal–organic frameworks (MOFs) that contain various transition metals is a challenging task. In this study, we synthesized a polyoxometalate-based metal–organic framework (POMOF) named HRBNU-5 using a solvothermal method. HRBNU-5 is composed of Zn[N(C 4 H 9 ) 4 ][MnMo 6 O 18 {(OCH 2 ) 3 CNH 2 } 2 ]@Zn 3 (C 9 H 3 O 6 ) 2 ·6C 3 H 7 NO, which includes two components: Zn[N(C 4 H 9 ) 4 ][MnMo 6 O 18 {(OCH 2 ) 3 CNH 2 } 2 ]·3C 3 H 7 NO ({Zn[MnMo 6 ]}) and Zn 3 (C 9 H 3 O 6 ) 2 ·3C 3 H 7 NO (Zn-BTC). Structural characterization confirmed the host–guest structure, with Zn-BTC encapsulating {Zn[MnMo 6 ]}. In a three-electrode system, HRBNU-5 exhibited a specific capacitance of 851.3 F g −1 at a current density of 1 A/g and retained high stability (97.2 %) after 5000 cycles. Additionally, HRBNU-5 performed well in aqueous-symmetric/asymmetric supercapacitors (SSC/ASC) in terms of energy density and power density in a double-electrode system. Moreover, it demonstrated excellent catalytic performance in a 1.0 M KOH solution, with low overpotentials and Tafel slopes for hydrogen and oxygen evolution reactions: 177.1 mV (η 10 HER), 126.9 mV dec –1 and 370.3 mV (η 50 OER), 36.3 mV dec –1 , respectively, surpassing its precursors and most reported studies. HRBNU-5′s positive performance is attributed to its host–guest structure, high electron-transfer conductivity, and porous structure that enhances efficient mass transport. This work inspires the design of Anderson-type POMOF electrode materials with multiple active sites and a well-defined structure.
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Shuai Zhang,Linxiang Yang,Gaoyu Liu,Shengli Zhang,Qingsong Shan,Haibo Zeng
I–III–VI quantum dots (QDs) and derivatives (I, III, and VI are Ag+/Cu+, Ga3+/In3+, and S2–/Se2–, respectively) are the ideal candidates to replace II–VI (e.g., CdSe) and perovskite QDs due to their nontoxicity, pure color, high photoluminescence quantum yield (PLQY), and full visible coverage. However, the chaotic cation alignment in multielement systems can easily lead to the formation of multiple surface vacancies, highlighted as VI and VVI, leading to nonradiative recombination and nonequilibrium carrier distribution, which severely limit the performance improvement of materials and devices. Here, based on Zn–Ag–In–Ga–S QDs, we construct an ultrathin indium sulfide shell that can passivate electron vacancies and convert donor/acceptor level concentrations. The optimized In-rich 2-layer indium sulfide structure not only enhances the radiative recombination rate by preventing further VS formation but also achieves the typical DAP emission enhancement, achieving a significant increase in PLQY to 86.2% at 628 nm. Moreover, the optimized structure can mitigate the lattice distortion and make the carrier distribution in the interior of the QDs more balanced. On this basis, red QD light-emitting diodes (QLEDs) with the highest external quantum efficiency (EQE; 5.32%) to date were obtained, providing a novel scheme for improving I–III–VI QD-based QLED efficiency.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Huiting Xu,Huibin Liu,Wenyue Yang,Meng Li,Fan Zhao,Chunli Li,Junjie Qi,Honghai Wang,Wenchao Peng,Xiaobin Fan,Jiapeng Liu
Rechargeable aqueous zinc batteries (AZBs) are increasingly recognized as an alternative to conventional energy storage systems due to their environmentally safe nature, abundant zinc resources, and high theoretical capacity. However, the intercalation or surface redox mechanisms limit the development of AZBs cathode materials due to low specific capacity and energy density. The tellurium-based (Te) materials with conversion mechanisms are promising cathode materials for AZBs. Nevertheless, the slow kinetics are detrimental to the increase in specific capacity and energy density for Zn-Te battery. Therefore, a hierarchical structure of manganese oxide (MnO) hollow nanospheres loaded on nitrogen-doped carbon nanosheets (MnO@NC) was rationally designed and used as Te hosts (Te/MnO@NC) for Zn-Te battery. This hierarchical structure facilitates the loading of more Te species. Meanwhile, the MnO hollow nanospheres can expose more active sites, which can promote the kinetics of Te redox reactions thereby lowering the reaction energy barrier. The Te/MnO@NC cathode exhibits high specific capacity and high energy density (429 mAh g −1 and 407 Wh Kg −1 at 0.1 A g −1 ). Additionally, the conversion mechanism was investigated by systematic characterization and density functional theory (DFT) calculations. This study presents a new design platform for developing AZBs with high specific capacity and energy density.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Qifa Wan,Faming Zhang,Yifeng Xiong,Caiyun Shang
Using a simple and scalable solid-state synthesis process, a series of spinel-structured high-entropy oxides were systematically designed and synthesized in a Co–Mn–Fe–Cr–Ni–Zn–O system. These included (Co,Mn,Fe,Cr) 3 O 4 , (Co,Mn,Fe,Ni) 3 O 4 , (Co,Mn,Fe,Cr,Ni) 3 O 4 , (Co,Mn,Fe,Zn) 3 O 4 , (Co,Mn,Fe,Cr,Zn) 3 O 4 , (Co,Mn,Fe,Ni,Zn) 3 O 4 and (Co,Mn,Fe,Cr,Ni,Zn) 3 O 4 . The phase, microstructure and color evolution of 1/3Co 3 O 4 –1MnO-1/2Fe 2 O 3 -1/2Cr 2 O 3 –1NiO powders were studied without ZnO addition. These underwent four phase evolution processes and three color evolution processes before forming the final phase of black, octahedral (Co,Mn,Fe,Cr,Ni) 3 O 4 powders. The formation of an intermediate phase of (Co,Mn,Fe) 3 O 4 medium-entropy oxide powders served as the foundation for the creation of other high-entropy oxide powders. The infrared radiation properties of these synthesized medium and high-entropy oxides powders were evaluated in the near-infrared region at room temperature. Among these synthesized powders, the infrared emissivity values of (Co,Mn,Fe) 3 O 4 , (Co,Mn,Fe,Ni) 3 O 4 and (Co,Mn,Fe,Cr,Ni) 3 O 4 powders exceeded 0.8. All the synthesized powders exhibited excellent thermal stability after being annealed at high temperatures. Notably, after being annealed at high temperatures, the infrared emissivity values of these synthesized powders increased markedly without degradation, surpassing a value of 0.8, and displayed potential for applications in the field of high-temperature infrared energy savings.
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INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Xiaoli Lin,Panke Zhou,Yiqun Gao,Tao Li,Xiong Chen,Haohong Li,Rong Jiang,Zhirong Chen,Huidong Zheng
Polysulfide-based multilevel memorizers are promising as novel memorizers, in which the occurrence of Sn2– relaxation is key for their multilevel memory. However, the effects of crystal packing and the side group of organic ligands on Sn2– relaxation are still ambiguous. In this work, ionic [Zn(S6)2·Zn2(Bipy)2SO4 (1), Zn(S6)2·Zn(Pmbipy)3 (2)] and neutral [ZnS6(Ombipy) (3), ZnS6(Phen)2 (4)] Zn/polysulfide/organic complexes with different packing modes and structures of organic ligands have been synthesized and were fabricated as memory devices. In both ionic and neutral Zn complexes, the S62– relaxation will be blocked by steric hindrances due to the packing of counter-cations and hydrogen-bond restrictions. Consequently, only the binary memory performances can be seen in FTO/1/Ag, FTO/2/Ag, and FTO/4/Ag, which originate from the more condensed packing of conjugated ligands upon electrical stimulus. Interestingly, FTO/3/Ag illustrates the unique thermally triggered reversible binary–ternary switchable memory performance. In detail, after introducing a methyl group on the 6′-position of bipyridine in ZnS6(Ombipy) (3), the ring-to-chain relaxation of S62– anions at room temperature will be inhibited, but it can happen at a higher temperature of 120 °C, which has been verified by elongated S–S lengths and the strengthened C–H···S hydrogen bond upon heating. The rules drawn in this work will provide a useful guide for the design of stimulus-responsive memorizers that can be applied in special industries such as automobile, oil, and gas industries.
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Nano Research
·
2023
·
IF 9.9
Fang Diyi,Liu Chuanlei,Chen Yu,Peng Qilong,Wu Kongguo,Chen Yuxiang,Jiang Hao,Wu Yuan,Shen Benxian,Wu Qiumin,Wu Di,Sun Hui
Porous heterogeneous lyophobic systems (HLSs) find potential applications in energy restoring, dissipating, and absorbing. However, the development of controllable HLSs still lacks rational structure design of nanoporous materials matching the molecular sizes of adopted liquids. Besides that, thoroughly understanding the underlying transportation mechanism in the confined nano channels is greatly challenging. In this work, a series of Co/Zn bimetallic zeolitic imidazolate frameworks (ZIFs) with tunable structures were synthesized via regulating the Co to Zn ratios and employed to investigate the intrusion–extrusion of liquid water in confined nanopores. Structural characterizations confirm the heterometallic coordination in the Co/Zn-doped frameworks. Water intrusion–extrusion experiments unlock the relationship between the intrusion pressure and the nanopore size and realize the evolution of the HLSs between molecular spring and shock-absorber. In addition, cycling tests indicate the reversible structure change of Co/Zn ZIFs encountering pressure-induced water intrusion. In combination with molecular dynamics simulations, we present that the water multimers intrude into nanopores of ZIFs in chain-like forms along with dissociation of hydrogen bonds (HBs). Water molecules in the pre-intrusion state exhibit reduced HBs in response to the increase of pressure and linear structure with 1.6–3.0 HBs on average. After transition to the post-intrusion situation, the associative configuration of water tends to exhibit the tetrahedral structure. Herein, we highlight the roles of pore size and HB in synergically dominating the pressure-induced intrusion–extrusion of liquid water in hydrophobic nanopores. Furthermore, the present work can also guide the development of functional guest–host systems based on porous architectures.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Zhicheng Chen,Zongxu Li,Yuqiang Han,Yue Du,Dongbin Xiong,Xueqing Liu,Jianqing Zhou,Jun Wang,Yunlong Xie,Yahui Yang,Yisi Liu
Due to the high energy density and risk-free operation, flexible zinc–air batteries (ZABs) have the potential to be energy sources for wearable electronic devices. Nonetheless, the performance of quasi-solid-state gel electrolytes diminishes progressively throughout the ion-exchange process, primarily due to water evaporation on the exposed cathode side, which shortens the useful lifetime of ZABs. Herein, we propose a distinctive gel polymer electrolyte membrane comprising cotton fiber (CF) from natural long-staple cotton and polyvinyl acetate (PVA) to effectively extend the battery lifespan, which is due to that the addition of CF improves surface wettability , liquid absorption and retention, and ionic conductivity (1.53 × 10 −2 S cm −1 ) compared with single PVA electrolyte membrane. We also prepare a composite electrocatalyst (Co-N-C@GCF-950) by pyrolyzing the precursor of ZIF-67 in situ grown on the cotton fiber at 950 ℃. The flexible ZAB assembled with Co-N-C@GCF-950 as the cathode electrocatalyst and the CF-PVA membrane as the gel electrolyte shows a high open-circuit voltage of 1.5 V, and a stable charge-discharge voltage gap of 0.8 V for 11-h lifespan at a current density of 2 mA cm −2 under various bending conditions, which guides the future way of the application potential of environmental cotton fibers in the multiaspects for flexible metal-air batteries.
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危险品化学品经营许可证（带存储）