APPLIED CATALYSIS B-ENVIRONMENTAL
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2024
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IF 20.2
Hailong Tang,Yongqing Ma,Ganhong Zheng,Chuhong Zhu,Meiling Wang,Yilin Lu,Xiao Sun
Photocatalytic CH 4 conversion to CH 3 OH under mild conditions is undoubtedly an efficient strategy to realize CH 4 upgrading. In this work, in-situ formed highly reactive Fe IV =O complex with a bound Cl axial ligand was detected at ambient temperature and its contribution to CH 4 photoxidation to CH 3 OH was deeply investigated. Under optimized experimental condition, a high CH 3 OH yield of 3026.1 mmol mol Fe −1 (6.76 mmol g cat −1 h −1 ) with selectivity of 73.6 % was obtained during 8 h. Isotope labeling mass spectroscopy experiments manifested that O 2 was the only source of oxygen in products. The formation of Cl-(H 2 O) 4 Fe IV O complex was confirmed using low-temperature electron spin resonance spectroscopy and cryogenic Raman spectroscopy (ν(Fe O) = 828 cm −1 ). Through density functional theory (DFT) calculation, we showed that the Cl axial ligand acts as an “electron reservoir” during CH 4 conversion, i.e., electron acceptor during the process of CH 4 oxidation to CH 3 OH, while electron donor in CH 3 OH desorption. This not only lowered C-H cleavage energy, but also facilitated CH 3 OH desoption and inhibited overoxidation. As far as we know, Cl-(H 2 O) 4 Fe IV O is the first detected Fe IV O complex generated directly from O 2 and Fe 3+ at ambient temperature.
研究领域:
化学
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环境科学
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DOI
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-12
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IF 15.7
Chen Tiantian,Zhang Ganbing,Sun Hongwei,Hua Yetong,Yang Shu,Zhou Dandan,Di Haoxin,Xiong Yiling,Hou Shenghuai,Xu Hui,Zhang Lizhi
The microenvironment regulation of Fe-N 4 single atom catalysts (SACs) critically governs peroxymonosulfate (PMS) activation. Although conventional heteroatom substitution in primary coordination enhances activity, it disrupts Fe-N 4 symmetry and compromises stability. Herein, we propose oxygen doping in the secondary coordination shell to construct Fe-N 4 -C 6 O 2 SAC, which amplifies the localized electric field while preserving the pristine coordination symmetry, thus trading off its activity and stability. This approach suppresses Fe-N bond structural deformation (bond amplitude reduced from 0.875–3.175 Å to 0.925–2.975 Å) during PMS activation by lowering Fe center electron density to strengthen Fe-N bond, achieving extended catalytic durability (>240 h). Simultaneously, the weakened coordination field lowers the Fe=O σ* orbital energy, promoting electrophilic σ-attack of high-valent iron-oxo towards bisphenol A, and increasing its degradation rate by 41.6-fold. This work demonstrates secondary coordination engineering as a viable strategy to resolve the activity-stability trade-off in SAC design, offering promising perspectives for developing environmental catalysts.
研究领域:
环境科学
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催化化学
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Zhengming He,Cong Li,Jingzhen Su,Kai Zhang,Jiaxue zhu,Ren Cai,Yunshu Zhang,Jieming Yuan,Xiaohong Guan
Iron-based catalysts are generally used to activate oxidizing species, such as hydrogen peroxide by increasing homogeneous active substances like free radicals, to promote the degradation of organic matter. However, less attention has been paid to the reactions on the surface or the generation of heterogeneous metal-oxo species. Herein, oxygen vacancies (Vo) were introduced into Fe oxides by a calcination-induced hetero-atom doping modification. The characteristic peak of the heterogeneous hypervalent iron-oxo [≡Fe IV =O] species in the UV–Vis spectrum at 371 nm was observed. In the context of electrochemical experiment, Vo-rich Mn-Fe 2 O 3 significantly enhanced the electron conduction of sulfamethoxazole and H 2 O 2 , while simultaneously inhibiting the self-decomposition of potassium ferrate (Fe(VI)). Regarding the H 2 O 2 generated during the self-decomposition process of Fe(VI), Vo-rich Mn-Fe 2 O 3 can accelerate the degradation of sulfamethoxazole, increasing the reaction rate to 0.1081 min −1 (with a 30.05 % improvement in removal efficiency). Density functional theory calculations indicate that Vo leads to an enhanced capture of O atoms by the low-coordinated Fe atoms, promoting the anchoring of H 2 O 2 and the formation of the active ≡Fe IV =O with a higher spin state. This work proposes heterogeneous reactive species on the surface of metal oxidase, constructing Vo as the O atom capture sites in iron-based oxides to facilitate the formation of ≡Fe IV =O and the degradation of organic compounds.
研究领域:
环境化学
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催化科学
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材料化学
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环境污染与控制
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物理化学
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产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2023
·
IF 8.9
Lingxiang Zhao,Xinyue Cheng,Zhaoxian Wang,Enzhe Zhang,Zilian Liu,Huajing Zhou,Liang He,Qingqing Guan
Although alkaline sulfite activation of ferrate (Fe(VI)) has advantages of fast response and high activity for degradation of organic contaminants , the specific production pathways of active species and the pH conditions still hinder its widespread application. Based on this, our study constructed a novel advanced oxidation process of calcium sulfite (CaSO 3 ) could activated Fe(VI) continuously by Ca 2+ buffering and investigated the mechanism under different pH values and CaSO 3 dosages with ciprofloxacin as a target organic pollutant. The results showed that Ca 2+ stabilized the process at a neutral/weakly alkaline microenvironment of pH 7–8, which could alleviate the hydrolysis of ≡Fe IV =O by protons and iron hydroxyl groups. Besides, the removal of pollutants occurred efficiently when sulfate (SO 3 2− ) was excessive and had a 3:1 ratio of SO 3 2− to Fe(VI), achieving more than 99% removal of electron-rich phenolic organic pollutants within 2 min. By adding different radical scavengers and combining electrochemical analysis methods and electron paramagnetic resonance spectroscopy techniques to revealed that the main active species in Fe(VI)/CaSO 3 process were ≡Fe IV =O/≡Fe V =O. Furthermore, the reactivity of various sulfate species (such as SO 3 2− , SO 3 •− , SO 4 •− , SO 5 •− ) with Fe(VI) was calculated using density functional theory (DFT), and it was found that Fe(VI)–SO 3 2− reaction has a much lower energy barrier (−36.08 kcal/mol), indicating that SO 3 2− can readily activate Fe(VI) and generate ≡Fe IV =O to attack the atoms with high Fukui index (f - ) in organic pollutants. The above results confirm the feasibility of Fe(VI)/CaSO 3 process. Thus, this study can theoretically and practically prove that the main active species is ≡Fe IV =O, rather than SO 4 •− or • OH in Fe(VI)/CaSO 3 process.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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