JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2024
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IF 5.8
Guangyang Wang,Shaobai Sang,Qinghu Wang,Yawei Li,Heng Wang,Tianbin Zhu
MgCr 2 O 4 is a potential infrared radiation material for high-temperature furnaces energy-saving. However, poisonous Cr 6+ is easily formed in MgCr 2 O 4 -based materials during the preparation process, which is harmful to the environment. In this study, TiO 2 -doped MgCr 2 O 4 materials were prepared at 1600 ℃ by solid-phase sintering method. The effects of TiO 2 as a dopant on the infrared radiation properties of MgCr 2 O 4 and the leaching concentration of Cr 6+ were investigated, and the mechanism was discussed. Results show that the emissivity of MgCr 2 O 4 in both near-infrared and mid-infrared bands is enhanced with the increase of TiO 2 content, and the specimen MgCr 1.6 Ti 0.4 O 4.2 has the highest average emissivity in the 0.8–2.5 μm and 2.5–10.0 μm bands, which are 0.82 and 0.87, respectively. Moreover, the addition of TiO 2 significantly reduces the Cr 6+ content of MgCr 2 O 4 , with the Cr 6+ removal rate of MgCr 1.6 Ti 0.4 O 4.2 up to 84.2 %.
研究领域:
材料科学
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能源工程
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环境科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
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2023
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IF 5.2
Guangyang Wang,Shaobai Sang,Qinghu Wang,Yiran Sun,Yawei Li
It is crucial to develop high near- and mid-infrared emissivity radiation materials for energy-saving application in industrial furnaces at 1000 °C–1600 °C. In this study, NiO-doped MgCr 2 O 4 (MN), was prepared at different temperature using the solid-phase sintering method. The effect of temperature on infrared radiation property was investigated and the mechanism was discussed. The results show that the emissivity of MN in the near-to mid-infrared band is improved with the preparation temperature increasing from 1000 °C to 1600 °C. When the temperature is 1600 °C, the average infrared emissivity of MN is 0.88 in the wavelength range of 1.0–2.5 μm and 0.83 in the wavelength range of 2.5–14 μm. Compared with the samples treated at 1000 °C, the emissivity of MN is improved by 15 % in 1.0–2.5 μm waveband and 9 % in 2.5–14 μm waveband. The increase in temperature leads to an increase in the crystallinity of spinel. Moreover, at temperature above 1400 °C, the volatilization of Cr 2 O 3 results in an increase in the concentration of oxygen vacancies in spinel. At the same time, the Cr 5+ as well as Ni 3+ content increases and the forbidden bandwidth decreases, which were responsible for the increase of near- and mid-infrared radiation of MN.
研究领域:
材料科学
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热能工程
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光学性质
✓ 已验证
DOI
高影响因子
BIOMASS & BIOENERGY
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2025
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IF 5.8
Hui Hou,Jingang Yao,Fuli Yang,Hongqing Ma,Guiying Xu
CO 2 and green hydrogen for aromatics production are effective methods to mitigate CO 2 emissions. Herein, Mg 3-X Cr X O 4 spinel oxide was constructed via co-precipitation of Mg and Cr, followed by physical mixing with HZSM-11 to form a metal oxide-zeolite (OX-ZEO) bifunctional catalyst. The catalytic performance of this system in CO 2 aromatization was systematically evaluated. Notably, the designed catalysts followed a methanol-mediated pathway, overcoming limitations of the Anderson-Schulze-Flory distribution in aromatic hydrocarbon products. At varying Mg/Cr molar ratios, MgCr 2 O 4 /HZSM-11 exhibited the highest single-pass CO 2 conversion of 19.2 % and the highest aromatic selectivity of 75.2 % (excluding CO). Additionally, the optimal reaction conditions were determined for MgCr 2 O 4 /HZSM-11, achieving an excellent aromatic selectivity of 82.4 % and a CO 2 conversion of 22.6 % at 320 °C, a gas hourly space velocity (GHSV) of 1200 mL·gat −1 ·h −1 and a pressure of 3.5 MPa. After 100 h, the MgCr 2 O 4 /HZSM-11 tandem catalyst maintained substantial catalytic activity, with aromatic selectivity and CO 2 conversion of 79.3 % and 21.1 %, respectively. This strategy offers valuable insights for designing OX-ZEO bifunctional catalysts.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
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2024
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IF 2.4
Luo Shuxuan,Ma Xingyue,Chen Ziwei,Zhang Lei,Wang Wanlin,Sun Yongqi
Chromium, broadly present in metallurgical systems such as stainless steel slags and vanadium-bearing slags, tends to be in a trivalent form bound in spinel phases due to their ultrahigh stability. To explore the stability of chromium bearing spinels with different divalent cations, herein ACr 2 O 4 (A=Mg, Zn, Mn) spinels were synthesized and stability-tested under both alkaline and acidic environments. X-ray diffraction (XRD) and refinement results reveal that MnCr 2 O 4 exhibited the largest lattice parameters. X-ray photoelectron spectroscopy (XPS) results show that MnCr 2 O 4 had the highest oxygen vacancy concentration, potentially triggering structural instability, consistent with the Fourier-transform infrared (FTIR) and Raman analyses. To further investigate the stability of ACr 2 O 4 spinels in alkaline and acidic environments, we introduced CaO and SiO 2 , respectively, for high temperature calcinations. XRD analyses reveal that ACr 2 O 4 spinels exhibited a high instability under an alkaline condition, with an increasing degree of instability for MgCr 2 O 4 , ZnCr 2 O 4 , and MnCr 2 O 4 successively. We further quantified the relationship between the oxygen vacancy concentrations and the divalent cations containing in spinels as well as the spinel stabilities under an alkaline environment. Under an acidic condition, all ACr 2 O 4 spinels demonstrated a relatively strong structural stability. The understanding of formation and stability of chromium bearing spinels under different conditions could contribute to potential modifications and applications of spinels especially with regard to resource recycling in metallurgy.
研究领域:
材料科学
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环境科学
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冶金学
✓ 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）