ACS Sustainable Chemistry & Engineering
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2023
·
IF 8.4
Ming Ya,Jianghao Wang,Guangshe Li,Guichen Gao,Xu Zhao,Jiawen Cui,Haijun Wu,Liping Li
Spinel-type oxides exhibit great potential for the electrocatalytic oxygen evolution reaction (OER) due to their variable surficial composition and electronic structure. Herein, taking MgCo2O4 as a prototype, we put forward a surface engineering procedure to tailor the surface composition and valence state of cobalt ions for enhancing the OER performance. We discovered that the calcination temperature can finely tailor the ratio of Co/Mg and Co3+/Co2+ on the surface of MgCo2O4. MgCo2O4 with the maximum ratio of Co3+/Co2+ gives a current density of 10 mA cm–2 at a small overpotential of 283 mV. Such an overpotential is significantly lower than that of most cobalt-based spinel oxides ever reported. X-ray photoelectron spectra demonstrate that increasing the ratio of Co3+/Co2+ plays key roles in improving the OER performance. This work furnishes an instructive idea in pursuit of spinel-type oxides with high OER catalytic activity and stability by surface engineering.
研究领域:
材料科学
·
电化学
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DOI
高影响因子
Inorganic Chemistry Frontiers
·
2024
·
IF 6.1
Zhiyuan Liu,Qixuan Xiang,Hao Zhang,Xianglong Zhang,Huijun Tan,Yaping Zhao
MgCo2O4, a cobalt-based binary oxide, has garnered increasing attention as a promising active material for supercapacitor electrodes due to its enhanced conductivity and high theoretical capacitance. In this study, a novel mechanochemical approach was developed to convert stoichiometric MgO and Co2O3 into MgCo2O4. This innovative synthesis involved a one-step ball milling process that integrates two reaction steps. Initially, MgO reacted with water to form Mg(OH)2, followed by migration of Mg ions from Mg(OH)2 into the Co2O3 lattice to generate MgCo2O4. The milling parameters were optimized to enhance the conversion efficiency of MgCo2O4 through X-ray diffraction analysis. Complete conversion of MgCo2O4 was achieved with a single batch production capacity of 100 g, using a ratio of water volume to reactant weight of 2.0 mL g−1, a ball-to-powder ratio of 10 : 1, a revolution speed of 350 rpm, and a milling time of 80 hours. The synthesis mechanism was elucidated using X-ray photoelectron spectroscopy. The synthesized MgCo2O4 particles exhibited a small particle size of 117.8 nm and a high specific surface area of 63.3 m2 g−1. Based on these properties, the electrode exhibited a notable specific charge of 266.3 C g−1 at 0.1 A g−1, highlighting its potential as an excellent active material for supercapacitor electrodes. This study demonstrates a facile, green, cost-effective, and scalable production method for MgCo2O4, promoting its application in electrochemical energy storage.
研究领域:
材料科学
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电化学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
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IF 6.2
Guofei Zhang,Xin Yu,Zhenlong Wang,Sirong Li,Yunjiong Zhu,Yude Wang,Xuechun Xiao
Organic fuels are the main factors affecting the morphology, pore structure and catalytic active sites of metal oxides in solution combustion synthesis (SCS). However, due to the diversity of organic fuel structures, the specific role of organic fuel types on SCS is questionable. In this work, we compared the effects of five organic fuels on the thermocatalytic active sites of graded porous MgCo 2 O 4 nanomaterials . MgCo 2 O 4 (CA-MCO) prepared with citric acid as fuel has the largest specific surface area and the richest pore structure with the largest number of active sites. And the porous CA-MCO exhibited the best catalytic properties that the T HTD of AP decreased by 206.06 °C, the activation energy ( E a ) decreased by 104.58 kJ·mol −1 , and the reaction rate ( k ) increased by 2.49 s −1 . A possible catalytic mechanism for the thermal decomposition of AP was also proposed based on TG-MS and Hall effect tests. Finally, CA-MCO was applied to AP/HTPB-based composite solid propellants (CSPs), and the results showed that the introduction of CA-MCO significantly shortened the ignition delay time of the CSPs (From 29 ms to 8 ms), indicating its potential application in the CSPs.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
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IF 5.2
Zhiyuan Liu,Qixuan Xiang,Hao Zhang,Xianglong Zhang,Hunjun Tan,Yaping Zhao
MgCo 2 O 4 is a promising electrode material in electrochemical energy storage devices. In this work, the supercritical CO 2 -assisted solvothermal (SCAS) method was applied to synthesize MgCo 2 O 4 nanomaterials for the first time. The crystallite size of the MgCo 2 O 4 prepared by SCAS was significantly smaller than the one prepared by the ethanol solvothermal method, reaching 9.0 nm at a CO 2 pressure of 16 MPa. The as-prepared MgCo 2 O 4 nanospheres exhibited a special spherical structure with abundant irregular pores and a high specific surface area of 69.9 m 2 /g. X-ray photoelectron spectroscopy demonstrated that the Co 3+ /Co 2+ ratio of the MgCo 2 O 4 was increased by the SCAS method and the mechanism of synthesizing MgCo 2 O 4 nanospheres was explored. In addition, the MgCo 2 O 4 electrode material prepared by the SCAS method exhibited a high specific capacitance of 741 F/g at 0.1 A/g. The results confirm that the SCAS method can synthesize ultrafine MgCo 2 O 4 nanoparticles with special morphology and high specific surface area, which are expected to be applied in high-performance electrode materials.
研究领域:
材料科学
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电化学储能
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DOI
高影响因子
Canadian Journal of Chemistry
·
2022
·Vol. 100
·期 6
·
IF 1.051
Xia Gao,Peng Deng,Kehua Han,Yu Cao
The catalysis effects of MgCo2O4 nanosheets on the thermal decomposition of ammonium perchlorate (AP) were investigated. The MgCo2O4 nanosheets were synthesized with a facile free-template hydrothermal method. The chemical structure and micromorphology of MgCo2O4 nanosheets were characterized. Moreover, the catalysis thermal decomposition properties of AP using composite metal oxides MgCo2O4 nanosheets with different amounts (1 wt%, 3 wt%, and 5 wt%) as catalysts were investigated. The results showed that the reducing decomposition temperature of AP was 155.9 °C from 431 °C to 275.1 °C with 5 wt% MgCo2O4 added. The heat release of AP was increased by 907 J/g at least. In addition, the catalysis thermal decomposition mechanism of AP with the existence of MgCo2O4 nanosheets was explained. With the increasing temperature, the accumulated electrons (e–) and holes (h+) excited were activated at the surface of MgCo2O4 nanosheets, which accelerated H transfer from H atom of NH4+ to O atom of ClO4– and boosted AP decomposition.
研究领域:
材料科学
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化学
✓ 已验证
DOI
高影响因子
APPLIED OPTICS
·
2026
·Vol. 65
·期 15
·G17
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IF 1.7
Wang Xiaohui,Wang Xiaohui,Chen Huiyu,Wang Canjin,Yuan Xiaoming,Liu Wenyao,Tang Jun
The whispering gallery mode (WGM) microbottle resonators, with their natural liquid delivery channel structure and high-quality factor (Q), provide a crucial technical platform for precise microfluidic measurement. To further enhance the detection sensitivity, this research constructs a highly sensitive ethanol and acetone sensor by modifying the inner wall of a hollow microbottle resonator (HMR) with
nanomaterials. The results show that the sensitivity of the modified sensor is 0.0792 nm/% to ethanol solution, which is 2.1 times that of acetone. This indicates that the sensor has higher selectivity for ethanol. In addition, to further utilize the full-spectrum information, a multilayer perceptron (MLP) deep learning algorithm is introduced for intelligent analysis. The results indicate that the test accuracy for ethanol and acetone is 99.85% and 99.79%, respectively. With its high sensitivity and testing accuracy, this research provides support for the development of intelligent optical microcavity sensing.
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高影响因子
Environmental Science-Water Research & Technology
·
2018
·Vol. 4
·期 10
·1671-1684
·
IF 3.649
Ting Li,Taiwan Liao,Xiangde Su,Xiang Yu,Boping Han,Yi Zhu,Yuanming Zhang
In this paper, a series of cobalt-containing spinel oxides MCo2O4 (M = Mg, Mn, Cu) were prepared by a solution combustion method and used as novel adsorbents for phosphate for the first time. MgCo2O4 exhibited the highest adsorption capacity of up to 90.02 mg g−1, which was much greater than that of MnCo2O4, CuCo2O4 and most phosphate adsorbents. The adsorption isotherm and kinetics of MgCo2O4 followed the Langmuir monolayer model and the pseudo-second-order model, respectively. The phosphate adsorption of MgCo2O4 was found to be endothermic and nonspontaneous. Coexisting ions Cl−, NO3−, SO32−, and HCO3− did not affect the adsorption of phosphate on MgCo2O4, but the presence of CO32− would significantly interfere with the adsorption. Little decrease in removal efficiency after three adsorption–desorption cycles suggested its excellent stability and recyclability. Leakages of Co3+ and Mg2+ from MgCo2O4 were negligible when pH was higher than 3.0 during the adsorption process. The mechanism study revealed that the adsorption mechanism involved precipitation, electrostatic interaction and ligand exchange. The large surface area, high surface hydroxyl group content and more positive zeta potential resulted in high adsorption capacity. This work provided an excellent reference to constructing novel phosphate adsorbents and a deep insight into the study of the phosphate adsorption mechanism.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2022
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IF 9.965
Enhui Bao,Xianglin Ren,Runze Wu,Xiaohong Liu,Huiyu Chen,Yi Li,Chunju Xu
In this work, MgCo 2 O 4 microspheres (MgCo 2 O 4 MSs) and MgCo 2 O 4 nanoflakes (MgCo 2 O 4 NFs) were prepared by one-step and two-step synthetic method, respectively, and combined with a post annealing treatment. Both MSs and NFs electrode materials possessed porous structure and large specific surface areas. The electrochemical properties were evaluated using three-electrode as well as two-electrode systems. The MgCo 2 O 4 NFs delivered a specific capacity of 375.5C g −1 at 1 A g −1 together with a high rate performance (74.9%) at 10 A g −1 , while the MgCo 2 O 4 MSs exhibited 276.3C g −1 at the current density of 1 A g −1 . A hybrid supercapacitor (HSC) device was assembled with a cathode made from MgCo 2 O 4 and an anode made from activated carbon (AC) for evaluation of real applications, and it was able to run over a high voltage window (1.75 V). This MgCo 2 O 4 NFs//AC HSC delivered a high energy density ( E d , 35.4 W h kg −1 ) at 950.6 W kg −1 , and at the highest power density ( P d ) of 8905.0 W kg −1 , it could still hold 25.8 W h kg −1 . On the other hand, the MgCo 2 O 4 MSs//AC HSC device exhibited an E d of 32.4 W h kg −1 at a P d of 1048.0 W kg −1 . Both HSCs exhibited good long-term cycling stability due to no capacity decay over 6000 cycles at 6 A g −1 . The excellent electrochemical performance demonstrates that these MgCo 2 O 4 electrode materials, especially the MgCo 2 O 4 NFs, have great application potential for electrochemical energy storage. This synthesis method is simple and is possibly to be applied in synthesizing other transition metal oxides (TMOs)-based electrode materials with large surface area and outstanding electrochemical performance.
研究领域:
材料科学
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电化学
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能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2023
·Vol. 13
·期 24
·6951-6958
·
IF 5
Hui Zhang,Hui Han,Xuan Yang,Hongyu Ma,Zhifei Song,Xuqiang Ji
Active-site regeneration from d-band-center control engineering and electronic redistribution based on target-atom implantation is of enormous importance for efficient water oxidation. Here, low-activity Co catalytic sites of MgCo2O4 are reactivated for large-current (500 mA cm−2) and high-efficiency water oxidation through vanadium-atom electronic affinity synergy with Mg sites toward charge rearrangement around Co sites. Interestingly, very little vanadium (1.3 wt%) was implanted into MgCo2O4 to achieve atom-scale structure tailoring and electronic redistribution, reversing the Mg suppression effect on Co-site water oxidation of MgCo2O4. Vanadium-implantation-tailored MgCo2O4 coupled with MgO (V–MgCo2O4@MgO) exhibits significantly enhanced oxygen evolution reaction performance, with low overpotentials of 240 and 290 mV for 100 and 500 mA cm−2, respectively, in 1 M KOH. Operating at 500 mA cm−2, V–MgCo2O4@MgO has good catalytic stability for at least 20 hours. This work constructs excellent catalysts through atomic-level structural regulation and provides a new perspective for the principle of electronic-affinity synergy between V and Mg species toward Co–O bond optimization.
研究领域:
材料科学
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电化学
✓ 已验证
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DOI
高影响因子
危险品化学品经营许可证（带存储）