APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
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IF 14.229
Yuxian Wang,Lulu Chen,Hongbin Cao,Zhaoxu Chi,Chunmao Chen,Xiaoguang Duan,Yongbing Xie,Fei Qi,Weiyu Song,Jian Liu,Shaobin Wang
La-based perovskites are catalytically active owing to the oxygen vacancies, redox metal centers of B sites and surface hydroxyl groups. Nevertheless, the insights into these active centers on environmental catalysis are still insufficient. In this study, hierarchical mixed oxides perovskite microspheres were synthesized for catalytic ozonation over oxalic acid and benzotriazole. LaMn 4 O x , with LaMnO 3-δ as the dominant crystal phase, demonstrated superior catalytic activity to Mn 2 O 3 and LaMnO 3 synthesized from citric acid sol-gel method. Temperature-programmed desorption of NH 3 (NH 3 -TPD) and pyridine-Fourier transform infrared spectroscopy (pyridine-FTIR) tests proved Lewis acid as the main acid type. Temperature-programmed reduction of H 2 (H 2 -TPR), O 2 -TPD and X-ray photoelectron spectroscopy (XPS) analysis indicated the presence of oxygen vacancies and mixed valences of Mn in the crystal structure facilitated the catalytic process. Moreover, the content of oxygen vacancy was calculated by iodometric titration method. With the aid of theoretical calculations, oxygen vacancies were found to exhibit a strong affinity toward ozone adsorption, where ozone molecules spontaneously dissociated into reactive oxygen species (ROS) such as O 2 − and 1 O 2 . The B site of Mn facilitated ozone decomposition by extending the O O bond of ozone due to the electron transfer from Mn 3+ /Mn 4+ redox cycle. In-situ EPR and quenching tests confirmed the contribution of O 2 − and 1 O 2 in benzotriazole degradation along with OH. This study stepped further to unveil the ozone adsorption/decomposition and ROS generation on nanoscale perovskite-based composites.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
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2016
·Vol. 6
·期 74
·69855-69860
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IF 3.289
Baohuai Zhao,Rui Ran,Li Sun,Xingguo Guo,Xiaodong Wu,Duan Weng
The perovskite oxides LaMnO3+δ were prepared by a citrate method and then etched by acid solution with different times. After etching, the perovskite structures of all the catalysts remained, the surface area enlarged apparently, and the NO catalytic oxidation activities were obviously promoted by increasing the etching time. Long-term experiments revealed the acceptable stability of the etched catalysts. The favorable activities of the etched LaMnO3+δ catalysts were mainly due to their high specific surface area, abundant activated oxygen species and vacancies, as well as the higher valence state of Mn ions resulting from the loss of La3+ in the perovskite structure.
研究领域:
材料科学
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环境催化
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2019
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IF 5.155
Fawei Lin,Jiaming Shao,Hairong Tang,Yan Li,Zhihua Wang,Guanyi Chen,Dingkun Yuan,Kefa Cen
NO x control by catalytic oxidation combined with wet absorption has been a promising technology for the flue gas treatment of industrial boiler and furnace. LaMnO 3+δ perovskites were investigated as catalysts for NO oxidation. The comparison between metal substitution of La and Mn cations was researched. The activity results indicated that La site substitution was more favorable for NO oxidation than Mn site substitution. LaCoMnO exhibited the highest activity in NO oxidation with maximum value of 83.74% at 250 °C. That value further increased to 89.96% after acid etching (LaCoMnO-A), and closely, such high value of 89.78% was achieved at 220 °C. The surface area was significantly improved by acid etching, i.e., from 47.0 m 2 /g to 212.0 m 2 /g, Tremendous changes in crystalline structure and morphology were taken place, i.e., perovskites phase disappeared and MnO 2 was detected instead; compact amorphous particle morphology was replaced by multiple layer structure. Even more, Mn 4+ ions and oxygen vacancies accumulated on the surface were improved. Deservedly, the redox property was enhanced enormously, especially at low temperature. Subsequently, SO 2 poisoning tests were conducted at 250 °C under 20 ppm SO 2 . Interestingly, no decrease was observed for LaCoMnO-A within 480-min SO 2 poisoning test, which was totally contrasted with the nearly complete deactivation results of LaCoMnO. In-situ DRIFTS measurements validated nitrate disappeared and replaced by sulfate formation on the catalyst surface. Merely, under low-concentration SO 2 atmosphere, the monodentate nitrate and bidentate nitrate were destroyed, while the free nitrates exhibited higher resistance. Overall, the acid etching improved the catalyst resistance to SO 2 , which may have the potential to apply in the flue gas treatment of low-sulfur and sulfur-free fuel fired boiler and furnace.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry B
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2018
·Vol. 6
·期 37
·5931-5939
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IF 4.776
Lifei Song,Yun Zhu,Zezhou Yang,Ce Wang,Xiaofeng Lu
Nanomaterials with ABX3-type perovskite structure have attracted considerable and increasing attention due to their unique physical and chemical properties as well as promising applications in various fields. In this work, we have developed a simple electrospinning followed by a calcination process to prepare ABO3-type perovskite LaMnO3+δ nanofibers as efficient oxidase mimics for the detection of L-cysteine. The oxidase-like catalytic activity of the prepared LaMnO3+δ nanofibers is heavily dependent on the calcination temperature which results in different sizes of the LaMnO3+δ crystals and their crystallinity, and the maximum activity is achieved at the calcination temperature of 700 °C. Based on the high oxidase-like catalytic activity of the as-prepared perovskite LaMnO3+δ nanofibers, a simple and accurate colorimetric detection method towards L-cysteine has been developed. The detection limit is as low as 109.8 nM and an excellent selectivity for L-cysteine detection with common substances in human blood as interferents is also achieved. In addition, the LaMnO3+δ nanofibers can be retained as a monolithic membrane after the calcination process, making them an oxidase mimic for on-demand colorimetric sensing. This work reveals the promising prospects for the perovskite LaMnO3+δ materials in biosensing, medical diagnosis, food safety and environmental monitoring.
研究领域:
生物传感
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医学诊断
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食品安全
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环境监测
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产品关联
DOI
PubMed
高影响因子
Nano Energy
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2017
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IF 12.343
Long Kuai,Erjie Kan,Wei Cao,Marko Huttula,Sami Ollikkala,Taru Ahopelto,Ari-Pekka Honkanen,Simo Huotari,Wenhai Wang,Baoyou Geng
Oxygen reduction reaction (ORR) is the key reaction in various electrochemical energy devices. This work reports an inexpensive mesoporous LaMnO 3+δ perovskite for ORR with remarkable activity, synthesized by a facile aerosol-spray assisted approach. The mesoporous LaMnO 3+δ material shows a factor of 3.1 higher activity (at 0.9 V vs. RHE) than LaMnO 3 obtained from co-precipitation method (LMO-CP). Based on results of x-ray absorption near-edge spectroscopy (XANES), x-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis, we conclude that the chemical state of surface Mn and the high surface area are the sources to the notably enhanced activity. The study of Zn-air batteries device further confirmed a Pt/C comparable performance in the practical devices with the novel mesoporous LaMnO 3+δ catalyst, where the power density at 200 mA/cm 2 is only 2.1% lower than in the battery with same-loaded Pt/C catalyst. Therefore, the high mass activity and low-cost of Mn/La may make LaMnO 3+δ further approach to the application of electrochemical devices .
研究领域:
材料科学
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电化学
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PAPERS
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2026
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IF 2.7
Shen Houming,Shao Chendong,Wu Qirui,Sun Yikai,Rahman Sheikh Tamjidur,Wang Geming,Fan Peng
A series of perovskite-type LaMnO 3 (LMO) electrocatalysts (LMO-4, LMO-6, and LMO-8) with different oxygen contents (δ) has been successfully prepared by regulating the sintering temperature and time under nitrogen vs. air atmosphere sintered sample (LMO-0). We investigated the effects of microstructural features such as oxygen vacancies, adsorbed oxygen (O ads ), δ value, Mn 3+ /Mn 4+ ratio, and Mn-O bond lengths on their magnetic performance and oxygen evolution reaction (OER) activity and its intrinsic correlation mechanism. The nitrogen induces crystal structure transition from tripartite phase (LMO-0) to orthorhombic phase and increases the adsorbed oxygen (O ads ) content with the variation of annealing conditions. LMO-0 with a high δ-value and high Mn 4+ ratio exhibits a predominantly Mn 3+ -O-Mn 4+ ferromagnetic double-exchange interaction. Among the samples, LMO-0 exhibits the optimal OER activity with the lowest apparent kinetic slope and charge transfer resistance, which is attributed to its highest Mn 4+ ratio, oxygen vacancy content, and most significant electrochemically active area.
✓ 已验证
DOI
高影响因子
Applied Catalysis O: Open
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2024
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IF 0
Ximu Li,Haibo Yao,Jie Miao,Wei Zhou,Zongping Shao
This study aimed to construct a perovskite LaMnO 3+δ (LMO) with abundant oxygen vacancies (OVs) by an electrochemical approach at different potentials and figure out the role of OVs in peroxymonosulfate (PMS) activation. All modified samples achieved superior PMS activation activity than LMO (0.49 min −1 ) towards Rhodamine B (RhB) removal, LMO + 2 with more OVs showed the best performance (1.21 min −1 ). OVs regulated the Mn 3+ /Mn 4+ redox cycle and increased active sites, triggering RhB oxidation in LMO + 2/PMS system via a 1 O 2 -dominated nonradical pathway. These results suggest that perovskites efficiently enriched OVs through an electrochemical strategy and regulated activating PMS towards 1 O 2 -dominated oxidation.
研究领域:
环境科学
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材料科学
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电化学
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催化化学
✓ 已验证
DOI
危险品化学品经营许可证（带存储）