ACS Catalysis
·
2024
·
IF 11.3
Baoxin Ge,Pengyang Jiang,Biyi Chen,Caijin Huang
The orbital hybridization between metal and oxygen of perovskite catalysts can lower the overpotential and enhance the oxygen evolution reaction (OER) activity. This study combines density functional theory with experiments to clarify how Sr/Fe codoping modulates orbital hybridization and enhances OER catalytic activity of LaCoO3. The as-prepared La0.50Sr0.50Co0.75Fe0.25O3 shows remarkable performance with a low overpotential of 310 mV at 10 mA cm–2 current density and a 107.03 mV dec–1 Tafel slope, outperforming most state-of-the-art perovskite-based OER electrocatalysts. The experimental results confirm that Sr/Fe codoping enhances the expansion of Co–O–Co bond angles and strengthens the covalency of the Co–O bond in LaCoO3, leading to enhanced electrocatalytic activity. Moreover, increasing Sr doping reduces the distance between the Co 3d/O 2p center and the Fermi level, decreasing the energy difference between them and enhancing the degree of orbital hybridization between Co 3d and O 2p. As the degree of Co 3d/O 2p orbital hybridization increases, a higher charge transfer was found between the active center and intermediate product, OOH, reducing the energy barrier of the rate-determining step while lowering the overpotential. This study provides thorough insight into the rational design of OER catalysts based on orbital hybridization.
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高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2024
·
IF 5.3
Zhaoyang Zheng,Dong Han,Tianyu Zhang,An Du,Ruina Ma,Yongzhe Fan,Xue Zhao,Xiaoming Cao
The Co-depletion zone in WC–Co brazed joints is the main zone of joint failure, so it is crucial to explore novel processes to inhibit the Co-depletion zone and enhance the joint shear strength. In this study, a composite process of pre-plating Cu on the WC–Co surface + brazing was designed. Co-depletion zone reduces from 6 μm to 1 μm due to the Cu plating. Meanwhile, the formation of a plating fusion zone in the filler layer transforms TiCo with a thickness of 2.5 μm into a small number of TiCo particles. Moreover, the high concentration of Cu atoms in the vicinity of the WC particles at the interface changes the Co-segregation layer in the WC into a Cu-rich layer. The concentration of Cu in the filler layer leading to precipitation of TiCu and Ti 2 Cu particles. Ti 2 Cu particles encapsulated by ductile Ag–Cu–In ternary eutectic contribute to inhibit the cracks propagation. The shear strength of the joints was enhanced by 51.3 % to 295 MPa. The composite process of pre-plating on the base material surface + brazing has positive significance in inhibiting the excessive diffusion of elements from the base materials to the filler layer.
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高影响因子
APPLIED CATALYSIS A-GENERAL
·
2024
·
IF 4.7
Meidan Que,Yabo Wang,Ruochen Shi,Xun Sun,Jun Xu,Peihong Ma,Yanbo Sun,Jing Guan,Shengxia An
MIL-125(Ti) is well known for having stable structure, tunable electron structure, and multiple active sites, which is commonly studied in the field of photocatalysis . In this work, a series of rare earth (RE) doped MIL-125(Ti) (RE=Ce, Pr, Tm, Dy, Eu, and Sm) are prepared via the one-step hydrothermal method . Notably, Pr-MIL-125 displays a significantly enhanced catalytic performance than other RE-doped MIL-125, resulting in a maximal CO and CH 4 yield of 13.30 and 0.87 µmol·g −1 ·h −1 , respectively, which are 2.53-fold and 4.14-fold of the pristine MIL-125. The layered morphology endows Pr-MIL-125 with more active sites and facilitates the reaction of photoreduction CO 2 . Furthermore, the promoted photoactivities attributed to Pr ion dopant can act as electron transfer bridge and suppress charge recombination. This work would provide insight and guidance for designing RE-MOF based photocatalysts and enhancing the performance of photoreduction CO 2 .
研究领域:
材料化学
·
光催化
·
环境科学
·
无机化学
·
能源化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Kang An,Siran Zhang,Hong Wang,Ningyan Li,Ziyang Zhang,Yuan Liu
Direct hydrogenation of CO 2 into ethanol has been considered as an up-and-coming way to achieve CO 2 utilization. Ethanol can be generated by reverse water gas shift as well as CO hydrogenation over Co-based catalysts, where the regulation of Co 0 − Co δ+ is critical. Herein, we designed a supported Co-based catalyst doped with gallium, which was derived from Co-Al-O spinel precursor to facilitate synergistic catalyzing for CO 2 -to-ethanol transformation. The selectivity of ethanol reached 20.1 % in a continuous flow fixed micro-reactor over reduced CoGa 1.0 Al 1.0 O 4 /SiO 2 catalyst at 270 °C and 3.0 MPa. Results of characterization show that the existence of the strong interaction between Ga oxide and cobalt induced the configuration of Co 0 − Co δ+ active pairs, which promotes the process of ethanol synthesis by coupling the dissociation (CH x *)/non-dissociation (CO*) of the intermediates. The strategy by tuning the interaction between cobalt and gallium and/or aluminum oxide brings an avenue to tailor Co 0 − Co δ+ active pairs for the hydrogenation of CO and CO 2 .
研究领域:
催化化学
·
能源化学
·
材料化学
·
环境化学
·
工业催化
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Yafei Xue,Ge Ma,Xin Wang,Mingliang Jin,Eser Metin Akinoglu,Dan Luo,Lingling Shui
The development of high-efficiency oxygen electrocatalysts with earth-abundant transition metals rather than scarce noble metals has aroused growing interests due to their potential for energy storage and conversion applications. Herein, we developed a facile strategy to synthesize hollow tubular bimetallic Ni–Co oxide rooted with dense nanosheets for enhanced bifunctionality and facilitated redox reaction kinetics. Owing to the rational design of morphology and well-dispersed Ni and Co ions, the bimetallic samples exhibit admirable bifunctional electrocatalytic activities. This bimetallic Ni–Co oxide shows superior oxygen electrocatalytic performance in comparison with the monometallic Ni and Co oxides, according to the electrocatalytic synergistic effect from the bimetallic system. The optimized sample with the specific mass ratio of Ni and Co displays the oxygen reduction reaction (ORR) property comparable to commercial Pt/C and oxygen evolution reaction (OER) performance superior to commercial RuO2. The electrochemical tests and structural characterizations offer in-depth dissection on the electrocatalytic behaviors, especially the superb stability in both ORR and OER tests, as well as the outstanding resistance to methanol poisoning, representing a promising candidate in the renewable energy field.
研究领域:
材料科学
·
能源化学
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DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Jianhua Lü,Yuqin Fu,Dongmei Wang,Changli Lü
Luminescent silver nanoclusters (NCs) decorated with temperature-responsive copolymer P(NIPAm-co-MQ) have been fabricated in aqueous solution as a new fluorescent pH stimuli-responsive functional materials. P(NIPAm-co-MQ) was prepared by a conventional free-radical copolymerization of isopropylacrylamide (NIPAm) as thermo-responsive units and 5-(2-methacryloylethyloxymethyl)-8-quinolinol (MQ) as coordinating groups. The obtained fluorescent Ag NCs with various sizes showed different morphologies from single sphere to chain structure induced by the copolymer ligand. Upon changing the temperature, the fluorescence intensity of the Ag NCs exhibited temperature triggered response simultaneously. The copolymer stabilized Ag NCs as a pH probe exhibited reversible pH-dependent PL properties over the pH range of 3.04–5.25. With the pH decreased, the fluorescence intensity of Ag NCs under a UV lamp decreased and it was almost completely quenched after pH 3.04. Also, the properties of this fluorescence change with pH are reversible.
研究领域:
材料科学
·
纳米技术
·
分析化学
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DOI
高影响因子
ELECTROCHIMICA ACTA
·
2021
·
IF 6.901
Na Ye,Yanxin Bai,Zhao Jiang,Tao Fang
For the first time, PdCu/TaN C catalyst with a special core-shell structure is assembled, which exhibits high catalytic performance for methanol oxidation reaction (MOR) in alkaline medium (1326.95 A g Pd −1 ) and formic acid oxidation reaction (FAOR) in acidic medium (1052.63 A g Pd −1 ), 6.3 and 4.9 times those of the commercial Pd/C, respectively. According to the results of Tafel, Electrochemical Impedance Spectroscopy (EIS), CO stripping and chronoamperometry (CA), it is revealed that the reaction kinetics, anti-CO poisoning ability and stability of PdCu/TaN C for MOR and FAOR are all enhanced significantly. Density Functional Theory (DFT) calculations also indicate that the adsorption intensity of CO is weakened and the binding intensity of OH is enhanced on the Pd 3 Cu 1 /TaN(001) surface, which are beneficial to the removal of adsorbed CO and enhancement of the anti-CO poisoning ability. Combined with the characterization analysis and theoretical calculations, the good catalytic performance of PdCu/TaN C for MOR and FAOR can be attributed to the unique electronic structure and morphology from the effective interface, geometric effects and proper d-band center.
研究领域:
电化学
·
催化材料
·
理论计算
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 31
·15192-15199
·
IF 3.925
Zhihui Rao,Zhilin Li,Xiujian Zhao,Xiao Gong
Cs2AgInCl6 lead-free double perovskites are environmentally benign with easily modulated fluorescence. However, their wide band gap (∼3.3 eV) and forbidden optical transitions limit their visible application. Herein, we prepared Cs2AgInCl6 microcrystals (MCs) and corresponding doped samples (bismuth: Bi3+, samarium: Sm3+, and Bi3+–Sm3+) to achieve such a functionality by a precipitation method at low temperature (80 °C). Bi3+-doped Cs2AgInCl6 MCs introduce 1S0 to 1P1 absorption with a fluorescence enhancement at lower excitation energy (370 nm). Although the f–f transition of Sm3+ is parity forbidden, Bi3+–Sm3+ co-doped Cs2AgInCl6 MCs show a combination of luminescence in the visible range with two sharp additional spectral features at 567 and 600 nm, which are attributed to the 4G5/2 → 6H5/2 (∼567 nm) and 4G5/2 → 6H7/2 (∼600 nm) transitions of Sm3+ ions. We proposed a mechanism in which Cs2AgInCl6:Bi–Sm MCs achieve mutual enhancement of fluorescence through recombination of self-trapped excitons and energy-transfer transitions. Moreover, thermogravimetric (TG) analysis indicated that the materials have remarkable thermal stability. Afterwards, light-emitting diodes (LEDs) with bright yellow light were fabricated by combining Cs2AgInCl6:Bi–Sm MCs with a 365 nm chip, and the corresponding color coordinate is about (0.535, 0.440) with a 2000 K correlated color temperature (CCT).
研究领域:
材料科学
·
光学
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DOI
高影响因子
RARE METALS
·
2019
·Vol. 40
·期 1
·90-95
·
IF 1.785
Zhu Ying-Gang,Shang Chao-Qun,Wang Zhen-Yu,Zhang Jian-Qiao,Yang Ming-Yang,Cheng Hua,Lu Zhou-Guang
It is a big challenge to prepare non-rare metal and high-activity
electrocatalysts for oxygen reduction reaction (ORR). In this paper, a cobalt/carbon
nanotubes/chitosan composite gel was synthesized and then annealed under nitrogen
atmosphere to yield the cobalt and nitrogen co-modified carbon nanotubes (Co–N-CNTs)
nanocomposite electrocatalysts. In this strategy, the cobalt component considerably
enhanced the ORR activity and improved the degree of graphitic structure to increase the
electronic conductivity. The chitosan served as sustainable source for nitrogen doping.
The Co–N-CNTs exhibit excellent oxygen reduction reaction (ORR) electrocatalytic
activity due to the synergetic effect of Co species and N-doping. The Co–N-CNTs also
deliver excellent methanol tolerance and superior long-term durability to that of
commercial Pt/C, making it a promising ORR electrocatalyst.
研究领域:
材料科学
·
电化学
·
催化科学
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DOI
高影响因子
Journal of Macromolecular Science Part B-Physics
·
2021
·
IF 1.504
Meiling Yi,Zhihua Zhou,Wenjuan Liu,Tianlong Huang,Yanmin Zhao,Ping Chen,Ziwei Zhou,Dan Wang,Chao Zhang,Jianjun Fang
Among drug delivery systems, polymer microspheres have been proved to be the most promising carriers during the past several years. In this paper we describe the preparation of poly(L-lactide-co-glycolide-co-ε-caprolactone) (PLLGC) random terpolymer microspheres; their in-vitro degradation behaviors, including the changes of pH value, mass loss, molecular mass and surface morphology, were investigated during various degradation periods and compared with poly(lactic-co-glycolic acid) (PLGA) microspheres. The results showed that the introduction of the ε-caprolactone (ε-CL) unit reduced the degradation rate of the PLGA polymers. Therefore, we suggest the PLLGC microspheres with controllable degradation rate could supply a wider application future in drug delivery field than pure PLGA microspheres.
研究领域:
生物医学工程
·
药剂学
·
高分子科学
·
材料科学
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DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2026
·
IF 7.3
Lei Wang,Zekun Liu,Han Zhang,Pengfei Xu,Zhihao Liu,Bo Wang,Fei Ding,Jiadai Xue,Langping Wang,Yanji yang,Yong Chen,Yupeng Xu,Dianlong Wang,Bo Wang
Achieving near-zero internal stress without sacrificing strength remains a key challenge in Ni-based electroforming. Here, a Co/BSA co-regulation strategy is developed using benzenesulfonamide (BSA) as a dual-functional additive. Theoretical calculations and electrochemical measurements show that the benzene ring promotes interfacial adsorption, while activation of the sulfonamide group facilitates S incorporation, shifting the internal stress from tensile to compressive. Dynamic BSA adsorption suppresses lateral and through-thickness grain growth, promotes nucleation, and drives the transition from columnar grains to refined equiaxed grains. Meanwhile, facet-dependent BSA adsorption drives a concentration-dependent texture transition by shifting the deposition mode from grain-growth-dominated at low BSA concentrations to nucleation-dominated at high concentrations, favoring (200)- and (111)-oriented grains, respectively. The resulting texture evolution and S segregation cause a mismatch between the low-stress and high-hardness windows. To overcome this trade-off, Co is introduced for synergistic regulation. Co incorporation provides tensile-stress compensation and solid-solution strengthening, shifting the near-zero-stress state toward the high-strength region. Consequently, Co/BSA co-regulation enables the fabrication of near-zero-stress Ni-Co deposits with a hardness of 549.3 HV 0.1 and a tensile strength of 1598.2 MPa. This work provides a strategy for designing low-stress and high-strength electroformed Ni-based materials.
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Siyuan Wang,Wei Cai,Dongsheng Shi,Jingwu Zheng,Liang Qiao,Haibo Chen,Naoki Wakiya,Naonori Sakamoto,Takahiko Kawaguchi,Shenglei Che
High-performance SrFe 12 O 19 meets the current demands for lightweight and high-efficiency devices. In this study, Sm‒(Co/Zn/Ca) co-doped spherical SrFe 12 O 19 powders were synthesized via ultrasonic spray pyrolysis. This approach overcomes the limitation of single Sm doping in M-type strontium ferrite, which enhances coercivity but decreases saturation magnetization. The effects of co-doping on the structural and magnetic properties of the material were systematically investigated using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller, Mössbauer spectroscopy, and both room-temperature and low-temperature vibrating sample magnetometry (VSM). Among all the synthesized samples, SrSm 0.20 Zn 0.05 Fe 11.75 O 19 exhibited the highest saturation magnetization ( M s = 78.983 emu/g) while maintaining a coercivity of 7.097 kOe. Compared to SrSm 0.20 Fe 11.80 O 19 , Sm‒Zn co-doping resulted in a 20.12% increase in M s with only a 0.42% reduction in H cj . The results indicate that Zn 2+ preferentially substitutes Fe 3+ at the 4f 2 spin-down sites, reducing the contribution of reverse magnetic moments and thereby enhancing M s . Additionally, as a non-magnetic ion, Zn 2+ does not disrupt Fe‒O‒Fe super-exchange interactions, leading to a minimal reduction in H cj . In contrast, Ca 2+ tends to occupy the 12k and 2a spin-up sites, which reduces spin-up magnetic moments, negatively affecting M s enhancement. Moreover, Co 2+ , being a magnetic ion, disturbs Fe‒O‒Fe super-exchange interactions when incorporated into the SrFe 12 O 19 lattice, leading to a more significant decrease in coercivity. The magneton number ( n B ) calculated from low-temperature VSM confirmed the magnetic moment enhancement effect in the co-doped system, while Mössbauer spectroscopy provided further insights into the hyperfine interactions. This study demonstrates that the Sm‒(Co/Zn/Ca) co-doping strategy effectively balances M s and H cj , significantly improving the magnetic performance of SrFe 12 O 19 . Furthermore, ultrasonic spray pyrolysis proves to be a scalable and cost-effective synthesis method, showing great potential for the large-scale production of high-performance ferrite powders. These findings provide a theoretical foundation for optimizing SrFe 12 O 19 magnetic properties and offer new perspectives for its application in permanent magnet technology.
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