JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
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2021
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IF 3.995
Li Huang,Yiqing Zeng,Yibo Gao,Hu Wang,Yuhao Zong,Zhengfeng Chang,Shule Zhang,Pei Han,Yang Yu
The oxidation of SO 2 into SO 3 promote the formation of NH 4 HSO 4 (ABS), which can cover surface active sites catalyst, and then leading to the decrease of NH 3 -SCR De-NO x activity. In this work, phosphorus species were loaded on the V 2 O 5 -MoO 3 /TiO 2 De-NO x catalyst to enhance its SO 2 resistance via inhibiting the SO 2 /SO 3 conversion. XRD and N 2 -adsorption results showed that phosphorus has little impact on the structure and pore property of the catalyst. The results of XPS , H 2 -TPR, and NH 3 -TPD analyses illustrated that suitable amount of phosphorus (1%) increases the content of polymeric vanadate and chemisorbed oxygen (O α ) of the catalyst, which is benefit to the SCR process. Phosphorus species decreases the SO 2 absorbability and SO 2 oxidation activity of V-Mo-P/Ti catalysts, thus it exhibits higher NH 3 -SCR activity than that of the P-free catalyst at presence of SO 2 due to the lower SO 2 /SO 3 conversion and fewer amount of NH 4 HSO 4 deposition.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
Environmental Chemistry
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2023
·Vol. 20
·期 6
·235-248
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IF 4.3
Hailiang Zhang,Long Jia,Yongfu Xu
Environmental context The process of ethylene ozonolysis is an essential source of CH2OO radicals, and the latter is an important oxidant for the atmospheric pollutant SO2. The accuracy of a widely used atmospheric chemistry model (Master Chemical Mechanism, MCM) in quantifying SO2 oxidation has not been evaluated. In this study, this accuracy was evaluated, and optimal parameters underpinned by data from smog chamber experiments.Rationale The oxidation of SO2 by CH2OO radicals in the ethylene-O3 system is one of the important pathways of sulfate aerosol formation, but the accuracy of Master Chemical Mechanism (MCM) simulation for this reaction was not evaluated, although the MCM has been widely used in previous studies.Methodology The oxidation of SO2 in the ethylene-O3 system was performed in detail under different conditions, which were used to evaluate the accuracy of MCM simulation for the reactions in this study.Results The experimental conditions of low RH and high initial SO2 concentration favour the SO2 oxidation in the ethylene ozonolysis, and the yield of CH2OO in the ethylene ozonolysis without irradiations was determined to be 0.43. The n-hexane (C6H14) oxidation intermediates can promote the SO2 oxidation rate by generating sulfur-containing organics in the aerosol water. The original MCM simulated SO2 consumption after 4-h reaction was more than 70% smaller than the measured results. By adjusting the yield of CH2OO and updating the reaction rate constants of CH2OO-related reactions (e.g. with SO2, H2O and organic acid), the difference between experiments and simulations decreased from 70% to 6.6%.Discussion The promotion effects of n-hexane on the oxidation of SO2 suggest that alkanes may be the precursors of sulfur-containing organics in the atmospheric environment. This study further confirms the effect of CH2OO on the oxidation of SO2 in the atmospheric environment and provides information on the performance of MCM simulation.
研究领域:
大气化学
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环境科学
✓ 已验证
DOI
高影响因子
Journal of the American Chemical Society
·
2024
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IF 14.4
Yiqun Cao,Jiarong Liu,Qingxin Ma,Chunyan Zhang,Peng Zhang,Tianzeng Chen,Yonghong Wang,Biwu Chu,Xiuhui Zhang,Joseph S. Francisco,Hong He
We present a novel mechanism for the formation of photocatalytic oxidants in deliquescent NaCl particles, which can greatly promote the multiphase photo-oxidation of SO2 to produce sulfate. The photoexcitation of the [Cl––H3O+–O2] complex leads to the generation of Cl and OH radicals, which is the key reason for enhancing aqueous-phase oxidation and accelerating SO2 oxidation. The mass normalization rate of sulfate production from the multiphase photoreaction of SO2 on NaCl droplets could be estimated to be 0.80 × 10–4 μg·h–1 at 72% RH and 1.33 × 10–4 μg·h–1 at 81% RH, which is equivalent to the known O3 liquid-phase oxidation mechanism. Our findings highlight the significance of multiphase photo-oxidation of SO2 on NaCl particles as a non-negligible source of sulfate in coastal areas. Furthermore, this study underscores the importance of Cl– photochemistry in the atmosphere.
研究领域:
大气化学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Yuwen Wang,Lingdong Kong,Jie Tan,Beibei Liu,Yixuan An,Lianghai Xia,Yu Lu,Qing Li,Lin Wang
Hydrogen peroxide (H2O2) plays a crucial role as an oxidizing agent within the tropospheric environment, making a substantial contribution to sulfate formation in hydrated aerosols and cloud and fog droplets. Field observations show that high levels of H2O2 are often observed in heavy haze events and polluted air. However, the source of H2O2 remains unclear. Here, using the droplets formed in situ by the deliquescence of hygroscopic compounds under a high relative humidity (RH), the formation of H2O2 by the photochemistry of imidazole-2-carbaldehyde (2-IC) under ultraviolet irradiation was explored. The results indicate that 2-IC produces IM–C•–OH and IM–C•═O radicals via H transfer itself to its excited triplet state and generates H2O2 and organic peroxides in the presence of O2, which has an evident oxidizing effect on SO2, suggesting the potential involvement of this pathway in the formation of atmospheric sulfate. H2O2 formation is limited in acidic droplets or droplets containing ammonium ions, and no H2O2 is detected in droplets containing nitrate, whereas droplets containing citric acid have an obvious promotion effect on H2O2 formation. These findings provide valuable insights into the behaviors of atmospheric photosensitizers, the source of H2O2, and the formation of sulfate in atmospheric droplets.
研究领域:
大气化学
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环境科学
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物理化学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2025
·
IF 11.3
Wenjie Liao,Ling Zhou,Xiaoqiang Wang,Yue Liu,Zhongbiao Wu
Both improving the activity and reducing SO3 emissions during selective catalytic reduction of NOx by the NH3 (NH3–SCR) process over commercial V–Ti-based catalysts remain a challenge. Herein, Ce and P cooperatively modified the VMo/Ti catalyst to address this challenge. Within the temperature range of 250–350 °C, the optimal VMoCeP/Ti catalyst achieved a NO conversion of more than 95% and maintained a SO2 oxidation ratio below 1.0%. The enhanced SCR activity of the modified catalyst could be attributed to the improvement in surface acidity and redox capacity by the addition of Ce and P, which would promote NH3 adsorption and activation. Meanwhile, Ce and P coaddition could regulate the surface structure of vanadyl species from predominantly polymeric to a more dimeric form, which could also promote the SCR reaction. More importantly, except for the suppressed sulfation of vanadium species, both a lower proportion of polymeric vanadyl species and the strong interactions among V–Ce–P species could raise the energy barrier of the decomposition of sulfated vanadium species into SO3, thereby inhibiting SO2 oxidation. This work provided novel insights into developing efficient SCR catalysts with low SO2 oxidation ratios for both the academic and industrial fields.
研究领域:
催化化学
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环境化学
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2023
·
IF 3.7
Xinbo Jing,Zhe Chen,Xue Cao,Qishen Huang,Pai Liu,Yun-hong Zhang
Sulfate formation is arguably the most important chemical process during urban haze events in China; however, the complex mechanism of sulfate formation from SO2 remains unresolved. Recent studies showed regionally transported sea spray aerosols (SSAs) and transition-metal ions (TMI)-catalyzed SO2 oxidation are major contributors to sulfate in haze events near coastal regions. To better understand the role of SSA and TMI catalysis, we investigated the reaction kinetics of Mn2+-catalyzed SO2 oxidation in NaCl microdroplets using confocal Raman spectroscopy coupled with a relative humidity (RH) and trace gas control system. We demonstrated that the reaction occurred on the droplet surface according to the linear correlation between the reaction rate and the droplet radius. The saturation concentration for both Mn2+ (0.001 mol/L at 1 ppm SO2) and SO2 (2 ppm at 10–5 mol/L Mn2+) implies the existence of an upper limit of the SO2 uptake coefficient, which is intercorrelated with Mn2+ and SO2 concentrations. The uptake coefficient increased with high ionic strength, while it remained constant when the pH ranged from 5 to 8. The uptake coefficient was on the order of 10–5 to 10–4, which is 10 to 100 times larger than that of the uncatalyzed autoxidation of SO2 and is overall higher than other mineral dust oxidation pathways.
研究领域:
大气化学
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环境科学
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气溶胶科学
✓ 已验证
产品关联
DOI
高影响因子
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