CATALYSIS COMMUNICATIONS
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2022
·
IF 3.51
Baohuai Zhao,Baofang Jin,Xiaodong Wu,Duan Weng,Rui Ran
A series of Sm-Mn oxides (SmMnO 3 , SmMn 2 O 5 and Sm 0.9 Ag 0.1 Mn 2 O 5 ) of perovskite-type and mullite crystal phases were synthesized for the catalytic oxidation of CO and C 3 H 8 . The Sm 0.9 Ag 0.1 Mn 2 O 5 composition showed the highest catalytic activity among the series of solids, especially for the CO oxidation to CO 2 with T 50 and T 90 values of 60 and 95 °C, respectively. The catalysts were characterized by powder XRD, Raman, BET, XPS, and H 2 -TPR. It was found that the catalytic performance of the solids was correlated well with their redox properties. Synergetic effects between Ag-related species and the mullite phase resulted in more active surface oxygen species and remarkably lowered the reduction temperature of the Sm 0.9 Ag 0.1 Mn 2 O 5 solid.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 39
·20922-20931
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IF 8.867
Jieyu Liu,Meng Yu,Xuewei Wang,Jie Wu,Changhong Wang,Lijun Zheng,Dachi Yang,Hui Liu,Yan Yao,Feng Lu,Weichao Wang
An alternative material SmMn2O5 mullite with regard to Pt/C is proposed to catalyze the oxygen reduction reaction (ORR) by combining density functional theory (DFT) calculations and experimental validations. Theoretical calculations are performed to investigate the bulk phase diagram, as well as the stability and electrocatalytic activity of the ORR under alkaline conditions for SmMn2O5 (001) surfaces, which are passivated by nitrogen atoms to avoid any spurious interference. The adsorptions of relevant ORR species (O*, OH*, OOH* and OO*) tend to compensate the coordination of manganese atoms to form Mn-centered octahedral or pyramidal crystal fields, and the corresponding binding energies fulfill a linear relationship. An oxygen molecule prefers to be reduced to OH−via a four-electron pathway and this prediction is verified by electrochemical measurements on the as-prepared SmMn2O5 catalyst with a nanorod structure. Volcano curves are obtained to describe the trends in theoretical ORR activity as a function of a single parameter, i.e. the oxygen binding energy. An overpotential of 0.43 V is obtained at the O* binding energy around 3.4 eV, which is close to the experimental observation (0.413 V) in this work. SmMn2O5 mullite exhibits favorable ORR activity and superior stability with only ∼5% decay in activity over 20 000 s of chronoamperometric operation in contrast to ∼15% decrease of Pt/C, making it a promising candidate for a cathode catalyst.
研究领域:
材料科学
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电化学
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产品关联
DOI
高影响因子
Catalysts
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2024
·Vol. 14
·期 2
·135
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IF 3.8
Baofang Jin,Yuxin Liu,Yue Ma,Zhenguo Li,Kaixiang Li,Shuang Liu,Rui Ran,Xiaodong Wu
A series of Ag-modified manganese-mullite (SmMn2O5) catalysts with different Ag contents (1, 3, and 6 wt.%) were prepared via a citric acid sol–gel method for catalytic soot oxidation. The catalysts were characterized by powder X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Raman spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy analysis (HRTEM), X-ray photoelectron spectroscopy (XPS), and H2temperature-programmed reduction (H2-TPR). The soot oxidation activity of the mullite was significantly promoted by the addition of silver and affected by the loading amount of the metal. Herein, the influences of silver loading on the metal size distribution and its interactions with the mullite were studied. Based on these characterizations, a possible soot oxidation reaction mechanism was proposed for silver-modified SmMn2O5.
研究领域:
催化材料
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环境科学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
·
IF 22.1
Yi Liu,Haolu Hu,Jiamin Zheng,Fei Xie,Huayu Gu,Sadegh Rostamnia,Fangfang Pan,Xiao Liu,Lizhi Zhang
Surface lattice oxygen (O latt ) over transition metal oxides plays a pivotal role in catalytic combustion of automobile exhaust. The insufficient O latt activity at low temperatures, however, remains the key problem restricting its practical application. To overcome this deficiency, we activated the O latt of mullite SmMn 2 O 5 through the interface fabrication with spinel Co 3 O 4 . The optimized Co 3 O 4 /SmMn 2 O 5 catalyst exhibited 90% conversion at 247 °C for the typical automobile exhaust propane combustion, 77 °C lower than the original SmMn 2 O 5 . Additionally, Co 3 O 4 /SmMn 2 O 5 showed extremely high stability even under harsh operating temperature (e.g., 800 °C). Experimental and theoretical calculation results revealed that the regulated interface of Co 3 O 4 /SmMn 2 O 5 facilitated the electrons transfer from SmMn 2 O 5 to Co 3 O 4 , contributing to the enhanced propane adsorption and catalytic oxidation activity due to the formation of electrophilic oxygen in SmMn 2 O 5 around the interface. This work can provide a basic understanding of the O latt activation for developing efficient automobile exhaust combustion catalysts.
研究领域:
材料科学
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催化化学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2025
·
IF 4.1
Xiao Li,Xue-wei Wang,Xiao-Ran Wen,Shi-qi Li,Kun Zhang,Jia-cheng Yu,Yan Guo
Mn-based mullite, with its unique structure featuring two distinct Mn coordination environments, has garnered significant attention in the research and development of oxygen reduction reaction (ORR) catalysts. The nucleation and growth of SmMn 2 O 5 were influenced by controlling the hydrothermal reaction time and temperature, resulting in SmMn 2 O 5 with varying degrees of crystallinity. With the increase of hydrothermal temperature and time, the crystallinity of SmMn 2 O 5 is enhanced, and the morphology changes from an amorphous lamellar structure to a finer and longer nanorod structure. SmMn 2 O 5 with an amorphous lamellar structure prepared at 150 °C for 3 h has a maximum specific surface area of 355.35 m 2 g −1 . The electrochemical results indicate that the amorphous lamellar SmMn 2 O 5 shows excellent ORR performance with a half-wave potential of 0.76 V. This is mainly due to the fact that crystallinity induces an increase in the number of oxygen vacancies, which increases the number of active sites and changes the valence state of Mn. The amorphous lamellar SmMn 2 O 5 was used as a cathode in zinc-air batteries with a power density of 119 mW/cm 2 , showing potential applications. This work demonstrates an effective and simple strategy for increasing the number of oxygen vacancies in SmMn 2 O 5 , which helps the development and application of SmMn 2 O 5 in the field of electrocatalysis.
研究领域:
材料科学
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电化学
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产品关联
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2025
·
IF 4.1
Shao-Hui Huang,Jie Wu,Jing Chi,Tai-Shen Yang,Jin-Chao Cao
Selective dissolution is an effective strategy to improve the catalytic performance. This method was used to regulate the surface structure of SmMn 2 O 5 through HNO 3 acidification to promote its oxygen reduction reaction (ORR) performance. The relationship between the structures and ORR performances of SmMn 2 O 5 acidified by different concentrations of HNO 3 (5-8 M) was investigated. HNO 3 can selectively dissolve part of Sm, which reduces Sm/Mn ratio, and increases Mn 4+ /Mn 3+ and surface adsorbed oxygen/lattice oxygen ratios on the catalyst surface. Especially, the increase of Mn 4+ content optimizes the adsorption of oxygen-containing intermediates on Mn 3+ active sites and enhances the ORR activity. When treated with 7 M HNO 3 for 10 h, the acidified SmMn 2 O 5 surface has suitable Mn 4+ /Mn 3+ ratio, exhibiting excellent ORR performance. Compared with SmMn 2 O 5 , the half-wave potential of the acidified SmMn 2 O 5 increases from 0.80 V to 0.83 V, and the diffusion-limited current density improves from 3.44 mA·cm −2 to 4.76 mA·cm −2 . Additionally, the synergistic catalytic mechanism of Mn 4+ with Mn 3+ active sites was well discussed.
研究领域:
材料科学
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电化学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
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IF 16.683
Baofang Jin,Baohuai Zhao,Shuang Liu,Zhenguo Li,Kaixiang Li,Rui Ran,Zhichun Si,Duan Weng,Wu Xiaodong
The mullite SmMn 2 O 5 (SMO) was modified with silver for soot oxidation by two methods, i.e. sol-gel (Ag/SMO-sg) and impregnation (Ag/SMO-im). The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectrometry (ICP-AES), H 2 -O 2 titration, H 2 temperature-programmed reduction (H 2 -TPR), CO temperature-programmed reduction (CO-TPR), soot temperature-programmed reduction (soot-TPR), O 2 temperature-programmed desorption (O 2 -TPD), cycled H 2 temperature-programmed reduction (cycled H 2 -TPR), NO temperature-programmed oxidation (NO-TPO) and soot temperature-programmed oxidation (soot-TPO). Metallic silver nanoparticles were observed in the mullite matrix for both the catalysts. For Ag/SMO-sg, the possible incorporation of silver into the mullite crystal cell and strong electronic interaction between the highly dispersed metal and the support increase the Mn 4+ /Mn 3+ ratio and create more structural defects in the mullite, resulting in boosted NO oxidation and thereby NO 2 -assisted soot combustion. The introduction of Ag can promote the generation/regeneration of active oxygen, which accelerates the ignition of soot in O 2 at low temperatures. Therefore, the sol-gel-synthesized Ag/SmMn 2 O 5 is highly promising for application in diesel particulate filters.
研究领域:
催化化学
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环境科学
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DOI
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 6
·期 14
·5580-5589
·
IF 5.287
Zijian Feng,Jianqiang Wang,Xiao Liu,Yanwei Wen,Rong Chen,Hongfeng Yin,Meiqing Shen,Bin Shan
A series of LaxSm1−xMn2Oδ (x = 0, 0.1, 0.3, 0.5) catalysts were synthesized through a co-precipitation method. The catalytic activity for NO oxidation was enhanced with La substitution, and the maximum activity was achieved at x = 0.3. XRD and HRTEM results revealed the formation of a multiphase oxide as well as the interface structure between the mullite (SmMn2O5) phase and Mn-rich perovskite (La0.96MnO3.05) phase. The main impact of different La/Sm molar ratios is the amount of surface adsorbed oxygen (Oads) and surface Mn4+ ions as revealed by XPS results. The NO oxidation performance was enhanced through La addition by promoting the decomposition of nitrate/nitrite species and desorption of NO2, improving the reducibility of surface adsorbed oxygen, as determined by H2-TPR, NO + O2-TPRD and in situ DRIFTS studies. Mono-, bi-dentate and bridged nitrates formed on the surface were determined to be the primary reaction intermediates.
研究领域:
催化化学
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材料科学
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环境化学
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表面科学
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无机化学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
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2023
·Vol. 58
·期 6
·2494-2505
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IF 4.5
Ding Jiancai,Li Guangpeng,Ran Rui,Wu Xiaodong,Weng Duan,Yang Zhigang
Manganese-based mullite-type and perovskite-type mixed oxides were prepared by sol–gel method, and then palladium was loaded onto the mixed oxides by wet impregnation method. The catalytic performance for methane combustion, the influence of the supports, and the interaction between noble metal and the mixed oxides were investigated via experiments and theoretical calculations. The Pd/SmMn 2 O 5 catalyst exhibited superior low-temperature catalytic activity for methane combustion ( T 50 = 328 °C), which was superior to the Pd/perovskites catalysts and even better than Pd/Al 2 O 3 catalyst. It was ascribed to the abundant labile surface lattice oxygen species with high mobility and the uniformly dispersed Pd species on SmMn 2 O 5 , as revealed by TEM, CO-chemisorption, H 2 -TPR and XPS. DFT calculations verified the significant metal-support interaction via electron transfer between Pd and SmMn 2 O 5 , which further activated the lattice oxygen and improved the catalytic performance. It demonstrates the prospect of utilizing SmMn 2 O 5 mullite to optimize the typical noble metal catalysts. Graphical Abstract
研究领域:
催化化学
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材料科学
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环境科学
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产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
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2022
·
IF 5.6
Yun-Long Zhang,Xue-Wei Wang,Ke Ma,Xiao-Ran Wen,Zhong-Qing He,Zhi-Hao Yuan
In this work, sea urchin-like SmMn 2 O 5 /MnO 2 is synthesized by the hydrothermal method . Compared with SmMn 2 O 5 , SmMn 2 O 5 /MnO 2 has a half wave potential of 0.82 V (vs RHE), which shows excellent electrocatalytic activity of oxygen reduction reaction (ORR) in the alkaline media. More importantly, the composite of SmMn 2 O 5 /MnO 2 shows higher number of electron transfers , better stability of ORR, and stronger methanol-tolerant ability comparison with the commercial catalyst of Pt/C. The remarkable ORR activity is due to the formation of abundant oxygen vacancies and Mn 3+ , which are beneficial to the adsorption of oxygen species and the activation of O-O bond. The sea urchin-like morphology increases the specific surface area, and the tip-like synapses play an essential role in charge accumulation and rapid transfer. Moreover, the rechargeable zinc-air battery made of SmMn 2 O 5 /MnO 2 not only has a high peak power density, but also has excellent cycle stability of 450 h in long-term charge discharge measurement.
研究领域:
材料科学
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电化学
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能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Wenling Li,Heng Mao,Baofang Jin,Jiancai Ding,Yue Ma,Xiaodong Wu,Rui Ran,Zhichun Si,Duan Weng
SmMn 2 O 5 nanosheets with high specific surface area and (0 0 1) facet orientation were synthesized by a facile and efficient microwave-assisted hydrothermal strategy. The BET surface area of the leaf-like mullite (SMO-MW) reached 122 m 2 /g, which was about 4 times to that of counterpart (SMO-HT) prepared by conventional hydrothermal method. The relative intensity ratio of (0 0 1) facet to (2 1 1) in SMO-MW was 0.74 ~ 0.87, which was higher than 0.23 ~ 0.28 in SMO-HT. Compared with SMO-HT, the Mn x + reduction temperature of SMO-MW declined significantly ( Δ T = 63 °C for Mn 4+ →Mn 3+ , and Δ T = 76 °C for Mn 3+ →Mn 2+ ) in the temperature-programmed reduction with H 2 . Moreover, the weakened Mn-O bonds, higher concentration of Mn 4+ ions, and more chemisorbed oxygen were obtained via microwave irradiation. The pre-exponential factors of SMO-MW reached about 9 times comparing with those of SMO-HT, revealing the generation of more active sites. Impressively, the MW-500 calcined at 500 °C exhibited high catalytic performance with a 50% C 3 H 8 conversion at 243 °C, which was competitive with 1 wt% Pd/Al 2 O 3 catalyst. Meanwhile, it kept above 90% propane conversion during 80 h durability test at 285 °C. This study was expected to promote a new strategy on developing efficient mixed oxides catalysts for environmental and energy applications.
研究领域:
材料科学
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环境科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Hongming Liu,Jingxin Wang,Hai Xiong,Yue Chen,Jianzhong Xiao,Chao Wang
Restricted by an insufficient understanding of the compositional and structural characteristics of the sensing materials that affect the sensing performances, the YSZ-based CO gas sensor remains in a dilemma in terms of further promoting sensitivity, selectivity and long-term stability. In this work, two bimetallic oxides with different crystal structures, perovskite SmMnO 3 and mullite SmMn 2 O 5 , were prepared and adopted to elucidate the roles of the Mn 3+ , Mn 4+ and surface oxygen vacancies . Compared with SmMnO 3 , the coexisting coordination modes of Mn 3+ and Mn 4+ in SmMn 2 O 5 is conducive to generating oxygen vacancies. Furthermore, a SmMn 2 O 5 -based sensor with more oxygen vacancies demonstrates a relatively faster response/recovery speed and enhanced sensitivity of 2.05 times that of SmMnO 3 under the same operation conditions. Such work may broaden insight into the development of efficient sensing materials that introduce oxygen vacancies through the construction of phase structures without complicated operations. Overall, the sensor attached to SmMn 2 O 5 exhibits a low detection limit (5 ppm), a feasible response/recovery speed (24 s/28 s toward 40 ppm CO operating at 450 °C), satisfactory CO selectivity and long-term stability, highlighting its potential for CO monitoring in harsh environments.
研究领域:
材料科学
·
传感器技术
✓ 已验证
DOI
高影响因子
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