Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 35
·12037-12047
·
IF 6.4
Ruifeng Wu,Haibing Li,Yafei Liu,Aimin Chang,Bo Zhang
It is found that the linearization of the resistance–temperature curve for CaCu3Ti4O12 can be achieved by changing the energy band structure induced by Fe3+, but at the cost of decreasing temperature sensitivity. Here, a novel strategy is proposed to improve the thermal and dielectric properties of CaCu3Ti4O12 ceramics by (La,Fe)-co-doping. This can both linearize the resistance–temperature relationship by adjusting the energy band structure of the grains due to the Fe3+ doping and improve the temperature sensitivity by increasing the grain boundary potential barrier resulting from La3+ doping. The dielectric constant increases upon decreasing the grain boundary potential barrier and increasing the carrier concentration. Therefore, the dielectric constant and temperature sensitivity can be regulated by adjusting the characteristics of grains and grain boundary. This work bridges the relationship between thermal sensitivity and dielectric properties, and opens up a door for the development of a multifunctional coupler CaCu3Ti4O12 device.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Yanpeng Chen,Xing Zhu,Kongzhai Li,Yonggang Wei,Yane Zheng,Hua Wang
Syngas generation via thermochemical H2O–CO2 splitting relies heavily on a high-temperature decomposition of metal oxides into a reduced state. Meanwhile, typical chemical looping partial oxidation of methane to syngas suffers from the carbon deposition and the low selectivity toward syngas. To overcome these drawbacks, the partial oxidation of methane and H2O–CO2 splitting are coupled to consist of an alternative chemical looping redox scheme for the generation of Fischer–Tropsch (F–T)-ready syngas. The usability of lattice oxygen in a redox catalyst is facilitated, and its redox property is also thermodynamically optimized by using H2O and CO2 as soft oxidants, guaranteeing an effective generation of syngas from both redox steps. The carbon tolerance is greatly enhanced due to H2O or CO2 gasification in the reoxidization step. Experimental studies confirm the redox scheme by using CeO2–LaFeO3 redox catalyst, demonstrating generation of syngas with an H2/CO molar ratio around 2.0 in both methane partial oxidation and H2O–CO2 splitting steps over 30 repeated cycles at 850 °C. A syngas selectivity of 95% in methane partial oxidation and nearly 100% conversion of CO2 to CO can be achieved. Synergistic effect and competing reaction between H2O and CO2 splittings over the reduced redox catalyst are the key factors for the control of syngas composition and the intensification of CO2 splitting. The proposed approach can potentially be applied for production of F–T-ready syngas with an increased yield without the need for gas separation when compared to the state-of-the-art thermochemical splitting or methane chemical looping partial oxidation processes.
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MRS Advances
·
2022
·Vol. 7
·期 30
·736-740
·
IF 0
Guo Yong,Tan Junlang,Zhao Jingchang
In this work, (La, Eu) co-doped CaCu 3 Ti 4 O 12 ceramics (Ca 1− x La x Cu 3 Ti 4− x Eu x O 12 (CLCTEO)), x = 0.1, 0.3, and 0.5) were prepared by the solid-state method. The phase structure, morphologies, dielectric properties, and impedance spectrum were investigated methodically. The XRD of CLCTEO ceramics confirmed the formation of the complex perovskite with a residual amount of CaTiO 3 . The refined calculation found that the lattice parameter of CLCTEO ceramics will significantly increase due to the co-doping of La and Eu. The FESEM analysis shows that the grain size of co-doped CCTO is smaller, reaching the nanometer scale. Impedance indicates that the (La, Eu) co-doped CCTO ceramics have higher dielectric permittivity than the single-doped with La or Eu. The results show that co-doping is an effective method to improve the dielectric properties of CCTO ceramics. Graphical abstract
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MATERIALS LETTERS
·
2014
·
IF 2.269
T. Wei,Y.Q. Wang,C.Z. Zhao,X.X. Dong,J.H. Wang
Filled tetragonal tungsten bronze (TTB) structure Sr 4 La 2 Ti 4 Nb 6 O 30 co-doped by Er 3+ and Yb 3+ (SLTN: x Er 3+ – y Yb 3+ ) ceramics with different x and y were synthesized, and their crystal structure, upconversion photoluminescence (UC-PL), and dielectric permittivity were investigated for the first time. Under 980 nm infrared (IR) excitation, bright single-band UC green (515–570 nm) emission was observed for SLTN: x Er 3+ – y Yb 3+ ( x =0.05, y =0), however, featured two-bands UC emission (515–570 nm and 640–690 nm) was confirmed for all SLTN: x Er 3+ – y Yb 3+ ( x =0.05, y ≠0) samples. Two-photon energy transfer process was proved through pumping laser power dependence of emission intensity measurement. It is believed that energy back transfer (EBT) process should be mainly responsible for the two-bands UC emission. In addition, the dielectric properties were also discussed for SLTN: x Er 3+ – y Yb 3+ system.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
IF 4.598
Song Lv,Liya Ma,Xinyu Shen,Hua Tong
To achieve high-performance supercapacitors, nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons (CHC-SK) are successfully prepared by one-step carbonization. In the synthesis, two effective strategies of structure design and heteroatom doping are both used to increase capacitance of carbon materials. To control and design of structure, potassium citrate as a novel pore-former is introduced into chitosan hydrogel systems. It plays three roles in pore formation and thereby can be effective to optimize structure and improve surface area of CHC-SK. In addition, thiourea as binary doping of nitrogen and sulfur can effectively maximize the pseudocapacitance of CHC-SK. Therefore, CHC-SK with large surface area (1596.4 m 2 g −1 ) and high heteroatom content (5.43% for nitrogen, 2.62% for sulfur) show excellent electrochemical performances. The specific capacitance of CHC-SK reaches up to 366.8 F g −1 at 0.5 A g −1 . Even at the high current density of 10A g −1 , its capacitance retention is 97.1% for 10,000 cycles. This simple strategy for the synthesis of nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons with high specific capacitance has promising applications in the future.
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APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Cai Qi,Shu Zu,Xukun Zhu,Tong Zhang,Longyan Li,Li Song,Yachao Jin,Mingdao Zhang
Functional and active carbon material is of great concern in facilitating the performance of lithium-sulfur (Li-S) battery . In this work, we develop a bamboo-like nitrogen-doped carbon nanotubes (Co@NCNTs-2) with low cobalt metal content, which acts as not only the host matrix for sulfur loading but also an efficient catalyst for the adsorption and conversion of lithium polysulfides (LiPSs). The characterization results show that the Co particles are mainly encapsulated inside the Co@NCNTs-2, and the N species are mainly distributed on the outer surface of Co@NCNTs-2. The Co particles are the growth sites of carbon nanotubes and are wrapped by carbon to form Co@NCNTs-2. It is confirmed that the uniform graphitized structure contributes to charge transfer, while the enriched N species assist the trap and catalytic conversion of the polysulfides, thus helping to restrain the shuttle effect. As a result, the resultant Co@NCNTs-2-S cathode presents high reversible capacity at different current densities and exhibits superior cycling stability for 300 cycles at 0.5 C.
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Nature Communications
·
2025
·
IF 15.7
Gu Ming-Zheng,Min Yuan,Jiang Ling,Zhou Fu,Chen Qiao,Zhang Xiao-Jun,Chen Jie-Jie,Yu Han-Qing,Wang Guang-Feng
The challenge in precisely controlling the adsorption configuration of oxygen-binding intermediates in the branching path following C–C coupling constrains the directed selectivity of electroreduction CO 2 -to-ethanol. Here, we present a subsurface Co-doped CuS (Co-Sub-CuS) catalyst, which exhibits directed selectivity toward ethanol. We elucidate the role of subsurface doping in enhancing the oxophilicity of surface Cu sites, thereby facilitating the conversion of key intermediates ( * CHCHO * ) via the formation of surface-O bonds, guiding subsequent protonation towards ethanol. Moreover, the surface sulfur vacancies created by subsurface Co-doping help regulate the optimal distance between dual sites, facilitating asymmetric C–C coupling. Theoretical calculations combined with in-situ isotopic spectroscopy validate these views, and the branching pathway for converting * CHCO to * CHCHO * is captured. Consequently, in a membrane electrode assembly electrolyzer, the optimized Co-Sub-CuS achieves an ethanol Faradaic efficiency of 78.7% at a partial current density of 550.9 mA cm -2 , with stability over 305 h at industrial-level current density of 700 mA cm -2 . These findings provide a rational design for the development of directionally selective catalysts for CO 2 electroreduction.
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PubMed
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Qingping Xin,Zhaoqi Qu,Xinghui Zhang,Xingwei Wang,Jiaxin Wu,Dengdi Wu,Wei Huang,Mengke Wang,Ningning Gao,Xiaoli Ding,Yuzhong Zhang
Composite membranes, which consist of a multi-layer membrane structure comprising an ultra-thin dense separation layer and a porous support layer, are used for gas separation. However, issues such as poor adhesion between layers often arise. In this study, a novel reverse-induced diffusion method was employed to achieve the in situ growth of a covalent organic framework COF (TaPa-1) on one side of polyacrylonitrile (PAN) at room temperature, resulting in the formation of a tightly bonded gutter layer. Subsequently, a metal-organic framework MOF (NH 2 -ZIF-8) was secondarily grown in situ on the TaPa-1 membrane to prepare a PAN/COF-MOF composite membrane with stable interlayer bonding. The TaPa-1 layer, with high gas permeability, and the NH 2 -ZIF-8 layer due to sheltering effect, with high gas selectivity, act synergistically to enable efficient gas sieving and rapid transport. When treating simulated flue gas (CO₂/N₂ = 1:4), the gas separation selectivity of the PAN/COF-MOF composite membrane reach 29.9, with a CO₂ permeability of 825 GPU, achieving excellent CO₂ separation performance. In this study, the PAN/COF-MOF composite membrane is constructed using the reverse-induced diffusion method, achieving stable interlayer bonding and synergistic separation, demonstrating excellent CO₂ permeability and selectivity.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Zhidan Zheng,Wenbiao Liu,Xudong Huang,Huatian Chen,Zhijie Ren,Chengwu Zou,Huihua Tan,Qian Sun,Shuangliang Zhao
Pesticides and fertilizers are typically used in traditional agriculture. However, their incompatibility often causes efficacy reduction and environmental risks. Herein, we propose a new strategy for preparing polydopamine (PDA) multi-compartment microcapsules. The PDA nanocapsules can be synthesized through emulsion polymerization, with spherical morphology and a particle size range of 30–100 nm, which are used as shell materials to fabricate PDA multi-compartment microcapsules via spray drying technology. The as-prepared spherical microcapsules obtain a particle size range of 0.8–3.0 μm and good dispersibility, and can separately encapsulate the oil-soluble avermectin (AVM) and water-soluble urea to form Urea@AVM@PDA. In addition, these microcapsules can achieve controlled release of AVM and urea under different temperatures, pH, and NIR conditions, with good adhesion ability. The Urea@AVM@PDA also exhibits a lower LC 50 (18.416 μg/mL) than avermectin emulsifiable concentrate (AVM-EC, 23.923 μg/mL), and causes 36.67 % higher mortality of Plutella xylostella after ultraviolet treatment, which confirms the ultraviolet resistance of PDA shell layers. Furthermore, the potting experiment proves the Urea@AVM@PDA can promote pumpkin seedling growth.
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Processes
·
2025
·Vol. 13
·期 11
·3543
·
IF 2.8
Zhen Zhao,Meng Chen,Lei Wang
This study investigates the torrefaction of polyvinyl chloride (PVC) and cellulose, two major constituents of agricultural waste, with the aim of improving chlorine removal and enhancing the energy quality of the resulting solid products. Thermodynamic simulations using HSC Chemistry 9.0 were first conducted to predict equilibrium compositions, particularly chlorine-containing species. Thermogravimetric analysis (TGA) and coupled TGA-FTIR were employed to monitor mass loss and identify gaseous chlorine compounds. Based on these preliminary results, torrefaction experiments were carried out at temperatures of 250–300 °C and durations of 30–90 min. The results demonstrate a significant synergistic effect between cellulose and PVC during co-torrefaction, achieving 97% chlorine removal under optimal conditions (9:1 cellulose-to-PVC ratio, 250 °C, 30 min). This effective dechlorination helps mitigate Cl-induced corrosion and reduces the risk of dioxin formation in industrial applications, enabling the sustainable upcycling of PVC-contaminated biomass into clean solid fuels. Torrefaction temperature exerted a stronger influence than time on mass loss, yielding approximately 40% solid residue at 300 °C. While both solid and energy yields decreased with increasing temperature and time, the O/C and H/C atomic ratios decreased by 56% and 48%, respectively, indicating a substantial improvement in fuel properties. The observed synergy is attributed to cellulose-derived hydroxyl radicals promoting PVC dehydrochlorination. This process offers a scalable and economically viable pretreatment route for PVC-containing biomass, potentially reducing boiler corrosion and hazardous emissions.
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ELECTROCHIMICA ACTA
·
2025
·
IF 5.6
Hengzhi Zhang,Junyu Yuan,Yulin Liu,Rongzong Zheng,Chunyang Jia
Polyaniline (PANI) is a promising electrochromic (EC) material for adaptive camouflage due to its reversible infrared (IR) emissivity regulation via electrochemical redox processes under electrical stimulation. Nevertheless, structural instability originating from chain conformation degradation during prolonged electrochemical cycling, coupled with restricted polaron delocalization that impedes charge carrier mobility in π-conjugated systems, impose fundamental limitations on IR emissivity regulation, compromising operational durability and emissivity modulation efficiency. Constructing metal ion ligand coordination networks within PANI is a viable strategy for the simultaneous enhancement of optoelectronic performance and structural stability. Capitalizing on this coordination chemistry paradigm, a co-doping strategy combining protonic acid and zinc ion (Zn 2+ ) was developed to fabricate a high-performance PANI-based EC device. The optimized device exhibited an exceptional emissivity modulation amplitude (Δε = 0.65) within 8-14 μm while maintaining 98% emissivity modulation retention after continuous electrochemical switching over 1000 cycles. The results show that co-doping effectively enhances electron delocalization and polaron density in PANI chains. Moreover, the intra- and inter-chain coordination of Zn 2+ with PANI strengthens their interaction, thus improving the IR emissivity modulation range and electrochemical stability.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Lu Guo,Chengbo Kou,Daliang Fang,Liping Yang,Guorui Deng,Lei Zhu,Wen Ji,Zhonglei Zhu,Haojie Li,Kuo Meng,Xinyue Ma,Binling Li,Meng Ding,Hui Ying Yang
Porous graphene-based electrodes possess great potential in membrane capacitive deionization (MCDI) applications due to their high conductivity and specific capacitance. To further enhance their desalination performance, a MCDI system utilizing nanostructured porous graphene doped with trace amounts of Co and N atoms (CoNG) as the cathode, and N-doped graphene (NG) as the anode is proposed. The porous structure and co-doping of N and Co imparts CoNG with numerous active reaction sites and enhances its electrochemical stability. Besides, the combination of CoNG and NG electrode lowers the overall adsorption energy of the MCDI system. Under optimal conditions, a high desalination performance of 69.23 mg g −1 and a desalination rate of 2.307 mg g −1 min −1 have been achieved with an energy consumption of 0.36 Wh g −1 . This study highlights the potential of graphene-based materials in desalination and lays a foundation for further improvements in their desalination performance.
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