JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Yi-Shan Ouyang,Qing-Yuan Yang
Photocatalyst systems generally consist of catalysts and cocatalysts to realize light capture, charge carrier migration, and surface redox reactions. Developing a single photocatalyst that performs all functions while minimizing efficiency loss is extremely challenging. Herein, rod-shaped photocatalysts Co 3 O 4 /CoO/Co 2 P are designed and prepared using Co-MOF-74 as a template, which displays an outstanding H 2 generation rate of 6.00 mmol·g −1 ·h −1 when exposed to visible light irradiation. It is 12.8 times higher than pure Co 3 O 4 . Under light excitation, the photoinduced electrons migrate from the catalysts of Co 3 O 4 and CoO to the cocatalyst Co 2 P. The trapped electrons can subsequently undergo a reduction reaction to produce H 2 on the surface. Density functional theory calculations and spectroscopic measurements reveal that enhanced performance results from the extended lifetime of photogenerated carriers and higher charge transfer efficiency. The ingenious structure and interface design presented in this study may guide the general synthesis of metal oxide/metal phosphide homometallic composites for photocatalysis.
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2020
·
IF 5.647
Jia Liu,Jan Baeyens,Yimin Deng,Xianlu Wang,Huili Zhang
A major action to reduce CO 2 emissions is replacing fossil fuels by renewable energy sources . Matching the energy supply and demand by the mostly intermittent renewable resources (wind, solar, wave) is hence a hot topic, and energy storage has become crucial. Thermo-chemical energy storage (TCES) has a higher energy density than sensible and latent heat storage , and allows energy to be stored in the reaction products for multiple reuse and even off-site application. Design parameters are the equilibrium temperature , the reaction heat and the reaction rate, as obtained from both thermodynamic and kinetic assessments. Equilibrium temperatures of the selected metal oxides , Mn 2 O 3 /Mn 3 O 4 and Co 3 O 4 /CoO are between 1115 K and 1179 K. The present research studies both redox reactions as examples. Commercial Mn 2 O 3 and Co 3 O 4 were previously investigated in detail, and suffer from incomplete reversibility . The present study investigates the use of self-made Mn 2 O 3 and Co 3 O 4 mesoporous particles, of micrometer or nanometer scale, respectively. The average particle size of self-made Mn 2 O 3 particles is < 5 μm, with a BET surface area of 239.7 m 2 /g, and T eq of 1177 K at ambient pressure . Self-made Co 3 O 4 was of nano size, with average size of about 100 nm, a BET surface area of 54.2 m 2 /g, and T eq of 1109 K at ambient pressure. The redox reactions of these ultrafine particles are fast and nearly fully reversible. The effect of adding inert Al 2 O 3 or Fe 2 O 3 was also studied, but proven to offer no kinetic benefit, while reducing the reaction heat due to their inert additive character. The findings were used in the design of a 10 kW TCES pilot plant that is currently being tested in a concentrated solar furnace .
研究领域:
能源存储
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可再生能源
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材料科学
·
化学工程
·
热力学
·
动力学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Beiyang Guo,Jianfeng Ma,Yichao Shi,Kewen Zheng,Minghong Wu,Guofa Ren,Sridhar Komarneni
Here in, a system of Co 3 O 4 /CoO catalyst activated with the aid of bisulfite (NaHSO 3 ) was established for the decomposition of methylene blue (MB). The Co 3 O 4 /CoO material was designed by a two-step uniform precipitation and calcination method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) spectroscopy to detect the crystallinity, morphology, magnetic ability, element valence and the different types of free radicals, respectively. The efficient degradation of MB relies on the synergistic effect between the Co 3 O 4 /CoO catalyst and bisulfite (NaHSO 3 ) to generate some strongly oxidizing radicals, which could achieve a MB degradation rate of 90.7% within 40 min using this novel system. Additionally, the ferromagnetic property of Co 3 O 4 /CoO catalyst is expected to supply an excellent magnetic separation ability to help separate the solid catalyst from the aqueous solution. The novel catalyst system of Co 3 O 4 /CoO/NaHSO 3 may serve as a promising new system for wastewater treatment.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·Vol. 12
·期 4
·2618-2627
·
IF 1.5
Gongrui Wang,Yanshuang Meng,Lei Wang,Jun Xia,Fuliang Zhu,Yue Zhang
A novel yolk-shell structured Co 3 O 4 -CoO/Carbon (Co 3 O 4 -CoO/C) composite was prepared and applied as cathode active materials in lithium ion batteries. The composites were prepared through a facile copolymerization of ionic liquid and acrylonitrile, which were used as carbon sources, followed by carbonization. The yolk-shell structure of the composite endows the electrodes with excellent cycling performance due to improved electronic conductivity, reduced strain and depressed aggregation of active materials compared with bare Co 3 O 4 . Thus, the Co 3 O 4 -CoO/C composite showed a high reversible capacity and cycling life of 590 mAh·g -1 after 50 charge/discharge cycles at a current rate of 890 mAh·g -1 .
研究领域:
材料科学
·
电化学
·
储能
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2021
·
IF 6.583
Lei Liu,Zijian Zhou,Changqing Wang,Jie Xu,Hongqiang Xia,Guozhang Chang,Xiaowei Liu,Minghou Xu
Co 3 O 4 has been regarded as one of the most promising materials for redox energy storage due to its high theoretical conversion and complete redox reversibility. However, when undergoing charge-discharge cycles at high temperature, the material becomes sintered. The reversibility of the cobaltous oxides highly deteriorates, and the reoxidation reaction rate notably decreases. In addition, the obvious thermal hysteresis in the redox reaction process also limits the energy storage performance of the material. In this work, Co 3 O 4 with different micro-nanostructured morphologies is synthesized to evaluate its thermochemical energy storage performance. The capacity of the synthesized and commercial Co 3 O 4 is tested by thermogravimetric analysis (TGA). The fresh and recycled oxides are well characterized. Results suggest that all samples show complete reversibility, and the conversion decreases slightly after 30 cycles. The synthesized samples show better performance, especially cubic Co 3 O 4 . The reoxidation rate of the commercial sample is approximately 150 μmol/min/g, but that of the cubic sample is approximately 300-200 μmol/min/g in the first five cycles. The oxidation rate of the cubic sample decreases and finally remains at about 180 μmol/min/g from the 5th cycle to the 30th cycle. After 5 charge-discharge cycles, the commercial Co 3 O 4 is severely sintered, while the cubic oxides are only slightly sintered. After 30 redox cycles, the morphology of commercial oxides completely changed, while that of the cubic oxide retains the approximate shape of a cube. Moreover, the thermal hysteresis values of the commercial and cubic Co 3 O 4 are 24.7°C and 10.1°C, respectively, suggesting that the energy loss of cubic oxides is much smaller. The higher exothermic temperature of the cubic Co 3 O 4 redox process also indicates that it can supply high-grade thermal energy.
研究领域:
材料科学
·
能源存储
✓ 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）