ACS Applied Energy Materials
·
2022
·
IF 6.959
Bolei Shen,Haojing Zhang,Yingjie Wu,Hao Jiang,Yanjie Hu,Chunzhong Li
The demand for lithium compensation materials is becoming urgent as energy density requirements increase. As next-generation anodes, mixed silicon and carbon (Si–C) materials are limited by low efficiency in the first cycle owing to the formation of a solid electrolyte interphase film. However, most compensation materials are water- and oxygen-sensitive and exhibit low electrochemical activity and decomposition efficiency. In this study, water- and oxygen-stable lithium oxalate (Li2C2O4) was developed to enhance the capacity and cycle-life of the lithium-ion battery. Various metal oxides were screened to improve the electrochemical activity of Li2C2O4. Co3O4 exhibited the strongest catalytic performance, and the catalytic mechanism of Co3O4 on Li2C2O4 was studied by density functional theory. Ultrasonic atomization drying was used to combine Co3O4 quantum dots (Co3O4-QDs) with Li2C2O4 for improved efficiency. The electrochemical activity of the modified Li2C2O4 improved, and the decomposition voltage decreased from 4.65 to 4.0 V. The modified Li2C2O4 exhibits catalytic activity, and it can be used in LiFePO4, which has weak catalytic activity; the decomposition efficiency in the LiFePO4 system increased from 34.16 to 99.10%. In the Si–C//LiFePO4 full battery system, the first cycle discharge capacity increased from 80 to 160 mA h g–1; the lost capacity of the first cycle was fully compensated for. Additionally, the CO2 produced by Li2C2O4 decomposition could inhibit the decomposition of the electrolyte, further improving the cycle performance of the battery.
研究领域:
材料科学
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电化学
·
能源存储
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Lin Gong,Xiaodong Li,Qi Zhang,Bing Huang,Qiang Yang,Guangcheng Yang,Yousong Liu
Transition metal quantum dots (QDs) are ideal electrocatalysts due to their short ion diffusion path, high atom utilization and effective electron transfer properties. However, a lack of facile and large-scale synthesis strategy limits their industrial production and commercial application. In this study, a triaminoguanidine salt-induced one-step deflagration method is first reported for the ultrafast (hundreds of milliseconds) and gram-scale synthesis of Co 3 O 4 QDs-C 3 N 4 /rGO as an efficient oxygen reduction reaction (ORR) catalyst with high durability. The deflagration reaction process is carefully studied and the formation mechanism is proposed to explain the controllable synthesis of Co 3 O 4 QDs. An optimized sample is capable of achieving an excellent ORR performance in terms of an onset potential of 0.97 V (vs. RHE, equivalent to Pt/C) and the limited current density of −5.33 mA·cm −2 at 0.35 V (vs. RHE, ~7% higher than that of Pt/C). It is believed that this simple and effective synthesis strategy will open up an exciting new avenue to the future design and facile synthesis of Co 3 O 4 or other QDs-based functional materials.
研究领域:
材料科学
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电化学
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED POWDER TECHNOLOGY
·
2016
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IF 2.478
Junying Xue,Wenle Ma,Li Wang,Hongtao Cui
Co 3 O 4 quantum dots (QDs) with diameter of 3–5 nm were successfully prepared by a facile surfactant-free large-scale synthesis strategy at room temperature in ethanol. The formation of Co 3 O 4 QDs follows the sequence of Co 2+ + 2OH − → Co(OH) 2 → CoOOH → Co 3 O 4 . It is demonstrated that the dissolved oxygen and the bubbling of compressed air are the two keys for the synthesis of Co 3 O 4 QDs. The produced Co(OH) 2 was oxidized to CoOOH by the oxygen dissolving in ethanol. In order to synthesize pure phase Co 3 O 4 QDs, compressed air has to be bubbled into the solution vigorously to promote the decomposition of CoOOH by removing the oxygen evolved from the decomposition reaction. Due to small particle size and inherent properties of Co 3 O 4 , the QDs have excellent electrochemical performance and high long-term electrochemical stability.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 30
·10501-10514
·
IF 4.39
Xuqiang Hao,Dingzhou Xiang,Zhiliang Jin
Herein, a novel amorphous monodisperse Co3O4 quantum dots/3D hexagonal CdS single crystals (0D/3D Co3O4 QDs/CdS) p–n heterojunction was constructed by a simple hydrothermal and electrostatic self-assembly method. The amorphous monodispersed Co3O4 QDs (≈4.5 nm) are uniformly and tightly attached to the surface of the hexagonal CdS single crystals. The sample, 0.5% CQDs/CdS exhibits outstanding hydrogen evolution activity of 17.5 mmol h−1 g−1 with a turnover number (TON) of 4214, up to 10.3 times higher than that of pure CdS. The enhanced photocatalytic activity can be attributed to the synergistic effect of the p–n heterostructure and the quantum confinement effect of Co3O4 QDs, which significantly promoted the separation efficiency of photo-generated electrons and holes. Additionally, the sulfur vacancy also can act as electron trappers to improve carrier separation and electron transfer. The photoelectrochemical and time-resolved fluorescence (TRPL) results further certify the effective spatial charge separation. This work gives an insight into the design of the 0D/3D Co3O4 QDs/CdS p–n heterostructure for a highly efficient photocatalysis.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
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2022
·
IF 10.383
Enzhu Lin,Jiang Wu,Zihan Kang,Ni Qin,Kanghui Ke,Dinghua Bao
Piezocatalysis is one of the green and promising catalytic technologies for the degradation of organic pollutants. Surface modifications such as exposed facet engineering and surface decoration of nanoparticles (NPs) are simple but useful enhancement strategies for a catalytic system. However, the synergistic effect and mechanism of facet engineering and dual-cocatalyst decoration on piezocatalytic activity are still ambiguous and more investigations are expected. Herein, the piezocatalytic activities of BaTiO3 (BTO) polyhedrons with anisotropic {001} and {110} facets and BTO cubes with isotropic {001} facets were compared. Furthermore, BaTiO3 (BTO) convex polyhedrons with selectively deposited Ag NPs and uniformly loaded Co3O4 quantum dots (QDs) are rationally synthesized through photochemical deposition. The individual and synergistic effects of Ag NPs and Co3O4 QDs on the piezocatalytic activities are systematically studied. It was found that dual-cocatalyst-modified BTO possesses the highest piezocatalytic activity in methyl orange degradation, with a reaction constant k of 0.0539 min–1, around 5, 2.2, and 1.3 times higher than that of nonmodified and Ag NP- and Co3O4 QD-modified BTO, respectively. Moreover, dual-cocatalyst-decorated BTO also exhibits excellent piezocatalytic performance in nondye pollutant degradation, with ∼100% tetracycline hydrochloride decomposed in 60 min. By analyzing the contribution, quantifying the amount of different free radicals, and comparing the chemical states of surface elements before and after piezocatalytic measurements, it was inferred that facet-dependent Ag NPs acted as efficient electron-transport sites, while uniformly loaded Co3O4 QDs served as hole-transfer sites to fully facilitate the migration of electrons and holes in a piezocatalytic reaction. This research presents a rational and effectual modification strategy to enhance the piezocatalytic activity of piezocatalysts and gives a thorough discussion of the enhanced mechanism.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Zhiwei Zhao,Junyu Fan,Xiaoyong Deng,Jie Liu
In this study, Co 3 O 4 quantum dots decorated phosphorus-doped g-C 3 N 4 nanosheets was synthesized though one-step thermal polymerization method using vitamin B12 (VB12) as precursor of cobalt and phosphorus mixed with melamine. The prepared photocatalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), BET, transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and electrochemical measurements. Appropriate amount of introduced VB12 can improve photocatalytic activities while excess caused inhibition. The sample with the weight ratio of VB12 in precursors at 1% exhibited the optimum photodegradation efficiency for metronidazole (MTZ), about 2 times as higher as the removal rate of pure g-C 3 N 4 . Several effects on the photocatalytic activity was also investigated and the results showed that enough dissolved oxygen and presence of Fe 3+ was found to promote MTZ photodegradation, while NO 3 − , Ca 2+ and HCO 3 − would inhibit it. Superoxide radical O 2 − was identified as the dominate active specie in photodegradation process and possible enhancement mechanism of introduced VB12 for photocatalytic activities was proposed. It was inferred that the synergistic effect of generated Co 3 O 4 quantum dots and P-doped g-C 3 N 4 , including increasing the separation efficiency of photo-inducted electrons and holes, inhibiting the recombination process of them and decreasing the band gap energy, could be the reason for the better photocatalytic activity. At last, MTZ degradation pathway in the photosystem was determined.
研究领域:
材料科学
·
环境化学
·
光催化
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Jinping Liang,Ling Fu
Persulfate-based advanced oxidation process (PS-AOP) is a promising technology for in-depth wastewater treatment. Here, Co 3 O 4 quantum dots (QDs) decorated hierarchical C@Co 3 O 4 (C@Co 3 O 4 -Q5) was prepared by a facile route. The crystalline structure, micrograph and chemical composition of C@Co 3 O 4 -Q5 were characterized by XRD, SEM, TEM and XPS. Taking Rhodamine B (RhB) as a model contaminant, the influences of process parameters on the degradation performance were evaluated. Detailed reaction kinetics investigation indicated that, at elevated temperatures higher than 30 °C, RhB degradation rate approximately follows this expression: r = 1.022 × 1 0 7 e x p ( - 47850 / R T ) [ R h B ] [ P M S ] 0.36 , whereas the real energies for catalytic activation ( Eac ) and heat activation ( Eah ) were 16.231 kJ·mol −1 and 31.62 kJ·mol −1 , respectively. Reactive oxygen species (ROS) quenching experiments and EPR tests suggested that not the general held radical SO 4 − but the downstream OH and the nonradical ROS 1 O 2 co-contribute to RhB mineralization. Meanwhile, PMS activation mechanisms referring to OH and 1 O 2 generation were elaborated based on XPS discussion. It was revealed that Co 3 O 4 quantum dots and oxygen functional groups and/or oxygen defects on carbon surface cooperate to generate ROS. Additionally, 5 successive cycles confirmed C@Co 3 O 4 -Q5′s high stability and reusability. These findings provided new insights into carbon-loaded QDs catalysts for PMS-mediated micropollutants removal.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）