Carbon Energy
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2025
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IF 24.2
Zhao Sun,Kun Lei,Louise R. Smith,Nicholas F. Dummer,Richard J. Lewis,Haifeng Qi,Kieran J. Aggett,Stuart H. Taylor,Zhiqiang Sun,Graham J. Hutchings
Advanced oxygen carrier plays a pivotal role in various chemical looping processes, such as CO 2 splitting. However, oxygen carriers have been restricted by deactivation and inferior oxygen transferability at low temperatures. Herein, we design an Fe–O v –Ce–triggered phase-reversible CeO 2− x ·Fe·CaO ↔ CeO 2 ·Ca 2 Fe 2 O 5 oxygen carrier with strong electron-donating ability, which activates CO 2 at low temperatures and promotes oxygen transformation. Results reveal that the maximum CO 2 conversion and CO yield obtained with 50 mol% CeO 2− x ·Fe·CaO are, respectively, 426% and 53.6 times higher than those of Fe·CaO at 700°C. This unique multiphase material also retains exceptional redox durability, with no obvious deactivation after 100 splitting cycles. The addition of Ce promotes the formation of the Fe–O v –Ce structure, which acts as an activator, triggers CO 2 splitting, and lowers the energy barrier of C═O dissociation. The metallic Fe plays a role in consuming O 2− lattice transformed from Fe–O v –Ce, whereas CaO acts as a structure promoter that enables phase-reversible Fe 0 ↔ Fe 3+ looping.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Sustainable Energy & Fuels
·
2023
·Vol. 7
·期 4
·1027-1040
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IF 5.6
Ke Gao,Xianglei Liu,Qi Wang,Zhixing Jiang,Cheng Tian,Nan Sun,Yimin Xuan
Solar thermochemical CO2 splitting has emerged as a promising strategy for solar fuel production to alleviate climate change challenges and reduce the energy crisis. However, traditional redox materials still suffer from low CO production, poor cycle stability, high operating temperature, and large temperature swing, leading to low solar-to-fuel efficiency. Herein, Ce- and Al-doped SrMnO3 perovskites are proposed for high-performance solar thermochemical CO2 splitting within moderate temperature swing (1350/1100 °C). Sr0.6Ce0.4Mn0.8Al0.2O3 demonstrates a remarkable CO yield of 799.34 μmol g−1, which is ∼6.67 times as high as that of benchmark CeO2. Fast CO2 splitting kinetics of SCMA20 is demonstrated by the CO peak production rate enhanced by 142% compared with undoped SrMnO3. The proposed Sr0.6Ce0.4Mn0.8Al0.2O3 also exhibits excellent stability with no obvious deactivation or degradation over multiple cycles. The ultrahigh CO yield can be attributed to lower oxygen vacancy formation (3.65 eV) and migration energy (2.14 eV) as confirmed by DFT calculations, and the transformation of the first-order reaction (F1) to the second-order reaction (F2) compared to SrMnO3. This work provides a new path for high-performance solar thermochemical CO2 splitting with high CO production, fast reaction kinetics, good cycling stability, moderate temperature swing, and high solar absorptance.
研究领域:
材料科学
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能源化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Chenxuanzi Wang,Mingxuan Zhong,Yongcheng Cai,Zewei Zhang,Bo Xiao,Tingting Xu,Xun Wang
The chemical looping reforming coupled with CO 2 splitting (CLR-CS) offers a promising solution for syngas production and simultaneous decomposition of CO 2 . In this study, the Sr-Fe based oxygen carriers (OCs) were evaluated in CLR-CS using ethanol as fuel. The presence of Sr significantly improved the oxidation performance of iron oxides. The Sr element in fresh Sr-Fe based OCs mainly formed two crystal phases, including SrFe 12 O 19 and Sr 4 Fe 6 O 13 . Increasing the amount of Sr element made it easier to form Sr 4 Fe 6 O 13 crystal phase. The Sr 4 Fe 6 O 13 was favorable for syngas production, due to the higher surface oxygen vacancy formation energy with a range of 3.13–3.37 eV. However, the lower oxygen transfer capacity (OTC) of Sr 4 Fe 6 O 13 resulted in a lower CO yield in the of stage of CO 2 decomposition. Compared with Sr 4 Fe 6 O 13 , SrFe 12 O 19 exhibited the higher OTC and the higher reactivity of lattice oxygen, which was preferable to produce more CO 2 in the stage of ethanol reforming in fuel reactor. During the cycle tests, the crystalline phase of SrFe 12 O 19 didn’t regenerate under the CO 2 atmosphere but transformed into Sr 4 Fe 6 O 13 . It was attributed to the lower energy barrier of CO 2 oxidation on the oxygen defect surface of Sr 4 Fe 6 O 13 . The phase transformation of SrFe 12 O 19 accompanied the formation of Fe 3 O 4 . The excessive Fe 3 O 4 had poor stability and inactivated easily due to sintering and agglomeration in Sr1Fe4 and Sr1Fe6 samples. The Sr1Fe2, namely the molar ratio of SrO to Fe 2 O 3 of 1:2, exhibited the better performance for syngas (0.291 Nm 3 /kg OC) and CO (0.141 Nm 3 /kg OC) coproduction at 800 °C. Additionally, the Sr1Fe2 presented an excellent cyclic stability in 30 cycles due to the suitable proportion of Sr 4 Fe 6 O 13 and iron oxides formed, which maintained a high syngas yield and avoided sintering of iron oxides. Overall, the Sr1Fe2 is a promising OC candidate in CLR-CS process.
研究领域:
能源科学
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材料科学
✓ 已验证
DOI
高影响因子
Journal of the American Chemical Society
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2020
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IF 14.612
Xianhua Zhang,Chunlei Pei,Xin Chang,Sai Chen,Rui Liu,Zhi-Jian Zhao,Rentao Mu,Jinlong Gong
Modulating lattice oxygen in metal oxides that conducts partial oxidation of methane in balancing C–H activation and syngas selectivity remains challenging. This paper describes the discovery of distorting FeO6 octahedra in La1–xCexFeO3 (x = 0, 0.25 0.5, 0.75, 1) orthorhombic perovskites for the promotion of lattice oxygen activation. By combined electrical conductivity relaxation measurements and density functional theory calculations studies, this paper describes the enhancement of FeO6 octahedral distortion in La1–xCexFeO3 promoting their bulk oxygen mobility and surface oxygen exchange capability. Consequently, La0.5Ce0.5FeO3 with the highest FeO6 distortion achieves exceptional syngas productivity of ∼3 and 8 times higher than LaFeO3 and CeFeO3, respectively, in CH4 partial oxidation step with simultaneous high CO2 conversion (92%) in the CO2-splitting step at 850 °C. The results exemplify the feasibility to tailor the active lattice oxygen of perovskite by modulating the distortion of BO6 in ABO3, which ultimately influences their reaction performance in chemical looping processes.
研究领域:
材料化学
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催化化学
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能源化学
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无机固体化学
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化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）