INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
·
IF 4.326
Jiamin Huang,Guanghui Zhang,Jie Zhu,Mingrui Wang,Fanshu Ding,Chunshan Song,Xinwen Guo
The catalytic conversion of CO2 to higher alcohols (HAs, representing ethanol and alcohols with more than two carbon atoms) has been of great interest to mitigating the greenhouse effect and effectively utilizing CO2. However, most present catalysts have disadvantages of poor activity (conversion less than 30%) and selectivity (less than 10%) and high price. Herein, we report a Mn- and K-modified iron carbide catalyst that offers a CO2 conversion higher than 40% and a selectivity of higher alcohols exceeding 10%, and the proportion of propanol and butanol in alcohol products is more than 30%. Unpromoted iron carbide has a strong ability of hydrocarbon chain growth, leading to the fast formation of hydrocarbon products rather than HAs. However, on the Mn- and K-modified iron carbide catalyst, K is used to increase the surface C/H ratio of the catalyst by enhancing the adsorption of CO2 on the catalytic surface. The increased C/H ratio is indispensable to the formation of HAs, and the addition of Mn promoter dramatically improves the production of HAs, especially the formation of propanol and butanol. The synergistic effect between Mn and K on iron carbide is the key to produce HAs. In addition, the Mn- and K-modified iron carbide is of low cost, which can potentially provide an alternative for the hydrogenation of CO2 to produce valuable chemicals.
研究领域:
催化化学
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环境科学
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能源科学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2024
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IF 9.4
Gang Xing,Xuan Liu,Yazhen Jia,Jialin Wu,Liming Chai,Wenjie Zhai,Zhaojun Wu,Jing Kong,Jianbin Zhang
Synthesis of catalysts with high catalytic degradation activity for formaldehyde (HCHO) at room temperature is highly desirable for indoor air quality control. Herein, a novel K-Mn 3 O 4 @CeO 2 catalyst with excellent catalytic oxidation activity toward HCHO at near room temperature was reported. In particular, the K addition in K-Mn 3 O 4 @CeO 2 considerably enhanced the oxidation activity, and importantly, 99.3 % conversion of 10 mL of a 40 mg/L HCHO solution at 30 °C for 14 h was achieved, with simultaneous strong cycling stability. Moreover, the addition of K species considerably influenced the chemical valence state of Mn from +4 ( ε -MnO 2 ) to +8/3 (Mn 3 O 4 ) on the surface of CeO 2 , which obviously changed the tunnel structure and the number of oxygen vacancies. One part of K species is uniformly dispersed on K-Mn 3 O 4 @CeO 2 , and the other part exists in the tunnel structure of Mn 3 O 4 @CeO 2 , which is mainly used to balance the negative charge of the tunnel and prevent collapse of the structure, providing enough active sites for the catalytic oxidation of HCHO. We observed a phase transition from tunneled KMnO 2 to Mn 3 O 4 to tunneled MnO 2 with the decreasing K + content, in which K-Mn 3 O 4 @CeO 2 exhibited higher HCHO oxidation activity. In addition, K-Mn 3 O 4 @CeO 2 exhibited lower oxygen vacancy formation and HCHO adsorption energies in aqueous solution based on density functional theory calculations. This is because the K species provide more active oxygen species and richer oxygen vacancies on the surface of K-Mn 3 O 4 @CeO 2 , promote the mobility of lattice oxygen and the room-temperature reduction properties of oxygen species, and enhance the ability of the catalyst to replenish the consumed oxygen species. Finally, a possible HCHO catalytic oxidation pathway on the surface of K-Mn 3 O 4 @CeO 2 catalyst is proposed.
研究领域:
环境科学
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催化化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Ruixuan Weng,Xueyi Mei,Zhaoliang Zhang,Ying Xin,Jiaqiang Xu,Yexin Zhang,Jian Zhang
Elimination of soot particulates using catalytic combustion technologies at lower temperatures remains a big challenge for diesel engines with the ever-lowering emission temperatures. We recently reported an electrified catalysis strategy that decreased the soot ignition temperature for 50% conversion ( T 50 ) to below 75 °C on potassium-supported antimony-tin oxides (K/ATO) (Mei et. al., Nature Catalysis, 2021, 4: 1002). However, the detailed affecting factors were not present for the sake of promptly enjoying this exiting progress. Herein, three important factors, including K loading amounts, electric power ramp rates and nitrogen oxides (NO x ), for the Electrically Powered Programmed Oxidation (EPPO) of soot were investigated on K/ATO. First, K loading enhances soot ignition but much higher K content (>1 wt%) is detrimental due to spoiling catalyst conductivity. Second, elevating the electric power ramp rate to 0.1 W min −1 reaches an apex with the promise of the balance of soot ignition conversion and energy efficiency. Finally, NO x , a promoter in traditional thermal catalysis, is overwhelmed by the tremendous active oxygen trigged from the electrification process, showing no effects on soot ignition. These findings are instructive to rational catalyst designs and vital to accelerate the industrial applications of the newly developed electrified catalytic soot combustion in the hybrid electric vehicle (HEV) aftertreatment system.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·Vol. 53
·期 6
·2526-2533
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IF 3.5
Jia-Min Lyu,Shen Yu,Zhan Liu,He-You Du,Ming-Hui Sun,Chun-Mu Guo,Yi-Long Wang,Yu Li,Li-Hua Chen,Bao-Lian Su
Excessive emission of CO2 into the atmosphere has severely impacted the global ecological environment. Converting CO2 into valuable chemicals and fuels is of great significance for sustainable development. However, low activity and undesirable selectivity often result from the inherent inertness of CO2. Herein, K- or/and Zn-modified Fe-based catalysts were prepared by an incipient-wetness impregnation method for CO2 hydrogenation via a cascade reaction. The results indicate that K species exist as K2O while Zn species exist as ZnFe2O4. In the CO2 hydrogenation pathway, K2O facilitates the adsorption of CO2 and restrains the adsorption of H2, accelerating the transformation of CO2 into C2–C4 olefins rather than paraffins while Zn species promote the dispersion of Fe species, leading to improved activity. Synergistically, a K- and Zn-modified Fe-based catalyst (2Zn–10K–Fe/Al) shows excellent catalytic CO2 hydrogenation activity, achieving a CO2 conversion of 77% which is 1.8 times that (42%) of the unmodified Fe-based catalyst (Fe/Al). Our catalyst also shows a significantly promoted selectivity to C2–C4 olefins of 17% in comparison with the Fe/Al catalyst (0%). It is envisioned that such a binary effect of elements might contribute to the low-cost and industrial production of Fe-based catalysts for selective CO2 conversion.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2024
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IF 6.7
Xixi Chen,Ruxing Gao,Qiang Wang,Kehao Hu,Fenfen Wang,Chao Deng,Lujing Xu,Chundong Zhang,Ki-Won Jun,Seok Ki Kim,Tiansheng Zhao,Hui Wan,Guofeng Guan
Direct hydrogenation of CO 2 to liquid hydrocarbons via modified Fischer-Tropsch synthesis represents an appealing and sustainable route for efficient CO 2 utilization. However, the selective production of liquid hydrocarbons remains a significant challenge. In this work, we designed a series of carbon-coated K/Fe-C catalysts with various K loadings (ranging from 0 to 8 wt%) that enhance C 5+ hydrocarbon selectivity during CO 2 hydrogenation. It is found that the 4 K/Fe-C catalyst exhibits the highest C 5+ selectivity of 54.78 % at CO 2 conversion of 32.40 % and good stability within 100 h time-on-stream. This is attributed to the high dispersion of the Fe nanoparticles and the confinement effect of porous carbon matrix on the aggregation of Fe nanoparticles, resulting in high catalytic activity and selectivity. Meanwhile, the well dispersed K on the porous carbon matrix can reduce the particle size of Fe nanoparticles and promote the production of iron carbide active species for CO 2 -FTS, thus facilitating the selective formation of C 5+ hydrocarbons. Moreover, we also discussed a possible reaction mechanism for the direct hydrogenation of CO 2 to C 5+ hydrocarbons over the K/Fe-C catalysts. This study provides deep insights into the design of efficient Fe-C catalysts for converting CO 2 to liquid hydrocarbons.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
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2025
·
IF 5.3
Haoyu Liu,Wei Liu,Yanlin Wang,Hong Yuan
The incorporation of mesopores into zeolite catalysts improves both reactant diffusion and the catalyst lifespan. In this study, a bolaform surfactant, C6H13–N+(CH3)2–C6H12–N+(CH3)2–C6H12–O–C6H4–O–C6H12–N+(CH3)2–C6H12–N+(CH3)2–C6H13 (BAM–6–6–6), was used to guide the synthesis of hierarchical MFI zeolite nanosheets (HMNs). The HMN pore structure and acidic sites were altered by varying the ratio of the K2SO4-derived K+ and Al sources in the initial gel. The X-ray diffraction, Fourier transform infrared spectroscopy, scanning electronic microscopy, and N2 adsorption/desorption were used to characterize these materials. The HMNs each had an interconnected hierarchical pore structure which consisted of MFI and mesoporous structures and mesopore-specific surface areas as high as 353.8 m2 g–1, indicating that the BAM–6–6–6 formed lamellar micelles based on π–π stacking. Temperature-programmed NH3 desorption and 27Al magic angle spinning nuclear magnetic resonance spectroscopy revealed that the intersection cavity of the HMN structure was enriched with acidic sites. Because of the layered HMN structure, which promoted diffusion and increased resistance to carbon deposition and buildup, the catalysts possessed good catalytic activity in cracking oleic acid. For the HMN zeolite, the light-olefin yield reached 50.02% at 500 °C, outweighing that of conventional ZSM-5 (39.80%), and the initial catalytic activity was retained for up to 50 h. Furthermore, for HMN, the hard coke loss (3.8%) was less than that for CZSM-5 (9.7%).
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2023
·Vol. 69
·期 10
·e18158
·
IF 3.7
Han Han,Xue Ye,Jie Yao,Xinhua Gao,Jinghao Yu,Lisheng Guo,Jie Li
The application of heterogeneous catalysts in dimethyl carbonate (DMC) synthesis from methanol is hindered by low activation efficiency of methanol to methoxy intermediates (CH 3 O*), which is the key intermediate for DMC generation. Herein, a catalyst of alkali metal K anchored on the CuO/ZnO oxide is rationally designed for offering Lewis acid–base pairs as dual active centers to improve the activation efficiency of methanol. Characterizations of CO 2 -TPD, NH 3 -TPD, XPS, and DRIFTS revealed that the addition of Lewis base K observably boosted the dissociation of methanol and combined with Lewis acid CuO/ZnO oxide to adsorb the formed CH 3 O* stably, thus synergistically promoted the transesterification. Finally, the CuO/ZnO-9%K 2 O catalyst exhibited the optimal catalytic activity, achieving a high yield of 74.4% with an excellent selectivity of 98.9% for DMC at a low temperature of 90°C. The strategy of constructing Lewis acid–base pairs provides a reference for the design of heterogeneous catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2021
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IF 13.084
Mengwei Gu,Sheng Dai,Runfa Qiu,Michael E. Ford,Chenxi Cao,Israel E. Wachs,Minghui Zhu
The reverse water–gas shift (RWGS) reaction is an initial and essential step for CO2 hydrogenation. In this study, Cu- and K-modified iron oxide catalysts were investigated with a series of in/ex-situ characterization techniques, including in situ XRD, in situ Raman, in situ DRIFTS quasi in situ XPS, quasi in situ HS-LEIS, H2-TPR, CO2-TPD, and TPSR. The surface structure of the catalyst is found to strongly depend on the presence of Cu and K, leading to diverse reducibility and basicity. Adding K to the iron-based catalyst alters the reaction from a redox pathway that proceeds on surface redox sites to an associative pathway that proceeds on surface redox and basic sites. Metallic Cu facilitates hydrogen dissociation and promotes both mechanisms by either boosting surface vacancy sites or supplying abundant surface hydrogen atoms. These findings would be beneficial for the rational design of CO2 hydrogenation catalysts.
研究领域:
催化化学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Xiaoli Jin,Huiqing Wang,Xiongtao Lv,Qing Lan,Teng Ge,Lin Guo,Xin Li,Hongxian Sun,Chenghua Ding,Yuwei Guo,Haiquan Xie,Liqun Ye
The development of bifunctional photocatalysts for enhancing hydrogen (H 2 ) and hydrogen peroxide (H 2 O 2 ) production from water is essential in addressing environmental and energy issues. However, the practical implementation of photocatalytic technology is still constrained by the inadequate separation of photo-generated charge carriers. Herein, potassium (K) atoms are introduced into the interlayers of graphitic carbon nitride (g-C 3 N 4 ) with a hollow hexagonal structure (K-TCN) and are coordinated with N atoms in adjacent layers. The presence of K–N coordination serves as a layer bridge, facilitating the separation of charge carriers. The hollow hexagonal structure reduces the distance over which photogenerated electrons migrate to the surface, thereby enhancing the reaction kinetics. Consequently, the optimized K-TCN exhibits a dramatically improved photocatalytic H 2 (941.6 μmol g −1 h −1 with platinum (Pt) as the cocatalyst) and H 2 O 2 (347.6 μmol g −1 h −1 ) generation as compared to hollow g-C 3 N 4 (TCN) and bulk g-C 3 N 4 nanosheet (CN) without K–N bridge under visible light irradiation. The unique design holds promising potential for developing highly efficient bifunctional photocatalysts towards producing renewable fuels and value-added chemicals.
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
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Junyuan Zhang,Ziwei Deng,Shuli Bai,Changyu Liu,Mengchen Zhang,Chao Peng,Xiaolong Xu,Jianbo Jia,Tiangang Luan
In this work, potassium acetate (KAc) was added during the synthesis of a Zn-Fe based metal-organic framework (Fe-ZIF-8) to increase the fixed amount of Fe while simultaneously enhancing the number of pores. Electrospinning was utilized to embed KAc-modified Fe-ZIF-8 (Fe-ZIF-8-Ac) into the polyacrylonitrile nanofiber mesh, to obtain a network composite (Fe@NC-Ac) with hierarchical porous structure. Fe@NC-Ac was co-pyrolyzed with thiourea , resulting in Fe, N, S co-doped carbon electrocatalyst . The electrochemical tests indicated that the prepared catalyst displayed relatively remarkable oxygen reduction reaction (ORR) catalytic activity, with an onset potential (E onset ) of 1.08 V (vs. reversible hydrogen electrode, RHE) and a half-wave potential (E 1/2 ) of 0.94 V, both higher than those of the commercial Pt/C (E onset = 0.95 V and E 1/2 = 0.84 V), respectively. Assembled into Zn-air batteries, the optimized catalyst exhibited higher open circuit voltage (1.698 V) and peak power density (90 mW cm −2 ) than those of the commercial 20 wt% Pt/C (1.402 V and 80 mW cm −2 ), respectively. This work provided a straightforward manufacturing strategy for the design of hierarchical porous carbon-based ORR catalysts with desirable performance.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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