FUEL
·
2020
·
IF 5.578
Muhammad Irfan,Aimin Li,Lei Zhang,Guozhao Ji,Yuan Gao
Catalytic gasification, coupled with in-situ CO 2 capture over Ni-CaO catalyst, is considered to be an effective approach for H 2 -rich and tar-free syngas production. However, the poor stability of Ni-CaO based catalyst raises a question regarding its large scale application. In this study, HfO 2 was used as a stabilizer and promoter for the Ni-CaO catalyst system. The stability of catalyst was evaluated through cyclic carbonation-calcination test with a thermogravimetric analyzer. The results showed that HfO 2 incorporated catalysts performed better stability towards cyclic CO 2 capture. The effect of different HfO 2 additions in catalyst, catalyst to municipal solid waste (C/MSW) ratio, gasification temperature, and moisture content (MC) of MSW was investigated on syngas composition, H 2 yield, dry gas yield (DGY) and product distribution (syngas, tar and char). The results indicated that H 2 yield was improved from 212 mL/g (without catalyst) to 442 mL/g with Ni-CaO (NC) catalyst and further improved with the application of HfO 2 promoted catalysts (Ni-CaO-HfO 2 ). The catalyst with 20% HfO 2 (NCH-20) exhibited maximum H 2 yield of 597 mL/g. Moreover, a significant reduction in tar content from 8.79 wt% (without catalyst), 3.19 wt% (with Ni-CaO) to 2.81 wt% (with NCH-20) was also recorded with HfO 2 promoted catalysts.
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APPLIED CATALYSIS A-GENERAL
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2020
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IF 5.006
Wanliang Yang,Meng Chen,Jiayuan Zhou,Yingnan Duan,Yinmin An,Mao Liu,Mengkui Tian
Porous carriers play an important role in the catalytic transformation of syngas into higher alcohols, which promises higher sustainability in C1 chemistry. In this work, a series of hierarchical hollow silica spheres (HHSS) supported Cu-Fe bimetal catalysts were successfully prepared through ultrasonic-assisted impregnation for higher alcohols synthesis from syngas. Structural characterization results indicate that the hierarchical hollow structure of HHSS support can be maintained and the Cu-Fe bimetallic nanoparticles are highly dispersed on HHSS surface. The catalytic performances of samples in the test of CO hydrogenation for higher alcohols synthesis were investigated. The results revealed that the conversion rate of CO and the selectivity of C 2+ OH alcohol increased first and then decreased with the decrease of the amount of Cu content in the Cu x Fe y @HHSS catalyst. The highest CO conversion, alcohol selectivity and STY ROH over Cu-Fe@HHSS catalyst are 65.1 %, 46.6 %, and 118.1 gkg −1 h −1 , respectively. It was found that a large number of CuFe 2 O 4 were formed in Cu-Fe@HHSS catalyst and also confirmed that the CuFe 2 O 4 spinel and CuO-CuFe 2 O 4 were converted to Cu-Fe 5 C 2 composite in the spent Cu-Fe@HHSS catalyst, which can enhance the synergy between Cu-Fe bimetals. Furthermore, copper and iron are highly dispersed on HHSS after the reaction, which enhances the structural stability of the catalyst. Based on the development and utilization of low-cost catalysts and the production of clean liquid fuels, HHSS has a great prospect of catalyst support in the energy field.
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ENERGY & FUELS
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2020
·
IF 3.421
Li Zhang,Yue Hu,Weibin Xu,Chuande Huang,Yang Su,Ming Tian,Yanyan Zhu,Huimin Gong,Xiaodong Wang
Iron-based oxides are promising oxygen carriers for chemical looping syngas production from methane; however, facile coke formation over reduced metallic Fe0 largely limits the syngas productivity. This work demonstrates that the introduction of Sn promoters into BaFe1–xSnxO3−δ perovskite oxides significantly restrains coke formation and improves the syngas yield to above 19.2 mmol/g with a H2/CO ratio of 2, which is 2.9-fold in comparison to BaFeO3−δ. Characterization results suggest that Sn cations are well-confined in the perovskite matrix by substitution of Fe. The Fe cations serve as main active sites for C–H bond activation with Sn cations as an oxygen reservoir, which donate the neighboring lattice oxygen to active Fe for selective methane oxidation. Besides, an intimate Fe–Sn interaction induces the formation of the FeSn alloy rather than metallic Fe0 under a reducing atmosphere, which restrains methane pyrolysis and notably improves the coke resistance. When Sn loading (x) increases to above 0.6, all Fe cations can be deeply reduced to the metallic state without coke accumulation and oxygen storage capacity reaches as high as ca. 6.5 mmol/g with nearly 100% syngas selectivity, which breaks the “seesaw” effect between oxygen supply and syngas selectivity for traditional iron-based materials. These results provide meaningful guidance for fabricating prospective oxygen carriers or catalysts with better anti-coke property for the chemical looping process or specific catalytic reactions.
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CATALYSIS TODAY
·
2020
·
IF 5.825
Hong Du,Miao Jiang,Xiuyun Ma,Peifang Yan,Z. Conrad Zhang
The rapid consumption of fossil resources and the grim environmental situation encourage the application of renewable and clean energy resources. Conversion of biomass, which is a kind of renewable, CO 2 neutral as well as abundant reserves carbon containing resource, is significantly important. The production of fuels from biomass by means of gasification and Fischer-Tropsch synthesis is one of the most promising routes for industrial applications. The wax-free liquid fuels synthesis directly from H 2 -deficient syngas similar to bio-gas is highly advantageous for reducing investment and operating cost. Thus, the Mn-promoted meso-ZSM-5 supported cobalt catalyst was applied for the production of wax-free liquid fuels by catalytic H 2 -deficient syngas conversion in this study. The performance of the reaction was influenced obviously by Mn content. The cobalt dispersion increased with the addition of Mn, whereas the reduction degree decreased after Mn doping. Then, the balance between the dispersion and reduction degree led to the change in CO uptake followed a volcanic curve. The catalyst with moderate amount of Mn (1 wt%) had the suitable cobalt particle size and the maximum CO uptake. Thus, the highest CO conversion was obtained over Co-1Mn/meso-ZSM-5 catalyst thanks to its maximum exposed active sites. The appropriate amount of Mn addition also resulted in the decreasing of CH 4 selectivity. The highest space time yield of liquid fuels was acquired over the Co-1Mn/meso-ZSM-5 catalyst from H 2 -deficient syngas conversion under the moderate conditions.
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CHEMICAL ENGINEERING JOURNAL
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2021
·
IF 13.273
Zhao Sun,Hanpeng Liu,Hongcun Bai,Shufan Yu,Christopher K. Russell,Liang Zeng,Zhiqiang Sun
Reducing anthropogenic CO 2 emissions has become a primary environmental concern for the present society, making the development of energy-efficient, net-negative CO 2 emitting technology paramount. Here, the Chemical looping deoxygenated gasification (CLDG) process is experimentally conducted to demonstrate the crucial role of deoxygenation on syngas refinement and CO 2 utilization via Fe 0 ↔ Fe 3+ looping. A reduction of 0.324 g CO 2 per gram pine wood biomass gasified is achieved, a 288% reduction in CO 2 emissions compared with that of biomass conversion without deoxygenation. The superiority of CLDG can be also reflected in syngas yields increased by 16.37% and a CO 2 concentration decreased by 44.16%. Results from the heat balance calculation indicate that both the gasifier and the regenerator are endothermic, which cannot achieve the auto-thermal operation of CLDG, thus requires an extra energy supply source. Density functional theory calculations elucidate that the active site of CO 2 adsorption is located at the three-phase interface of CaO(1 1 1), Fe(1 1 0), and amorphous carbon (AC). It is anticipated that CLDG has the potential to serve as an effective measure for reducing CO 2 emissions while promoting syngas yield and quality.
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高影响因子
Journal of CO2 Utilization
·
2019
·
IF 5.189
Qingxiang Ma,Yunxing Han,Qinhong Wei,Shengene Makpal,Xinhua Gao,Jianli Zhang,Tian-sheng Zhao
The bimodal mesoporous-macroporous alumina support was prepared via evaporation-induced self-assembly method (EISA), in which the polystyrene latex spheres with 100 nm diameter size were employed as sacrificial templates to fabricate macropores. The mesoporous-macroporous Al 2 O 3 -supported Ni catalyst (Ni/MM-A) was prepared by incipient-wetness impregnation method and applied for dry reforming of methane (DRM) to syngas. Characterizations by XRD, H 2 -TPR, SEM, and TEM revealed that the long-range ordered mesopore structure together with existing macropores was fabricated by using the EISA method, and the Ni particles were mainly stabilized inside the mesoporous channels of Al 2 O 3 support and the strong interaction between Ni and Al 2 O 3 was constructed. The Ni/MM-A catalyst exhibited more excellent catalytic performance in DRM reaction than that over Ni/M-A without macroporous structure. Stability tests for 100 h DRM reaction further indicated that the Ni/MM-A catalyst presented strong catalytic stability, which was significantly attributed to the macroporous structure that allowed the rapid mass transport, enhanced the tolerance to graphitic carbon and reduced the amount of graphitic carbon depositions.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Yajing Wang,Yane Zheng,Yuhao Wang,Kongzhai Li,Yaming Wang,Lihong Jiang,Xing Zhu,Yonggang Wei,Hua Wang
Chemical-looping reforming of methane (CLRM) offers an effective approach for the production of syngas . A series of Ce x Zr y Cu 1−x−y (x = 0.6, 0.7, y = 0–0.35) mixed oxides were successfully prepared by sol-gel method, and characterized by means of XRD , H 2 -TPR, BET, XPS , Raman and CH 4 -TPR. The addition of Cu and Zr ions caused the distortion of CeO 2 lattice and induced more oxygen vacancies , which promoted the mobility of lattice oxygen in the materials. Ce x Zr y Cu 1−x−y mixed oxides also owned smaller grain size and better thermal stability than pure CeO 2 -CuO mixed oxides. Among the series of Ce x Zr y Cu 1−x−y mixed oxides, the reducibility of Ce 0.6 Zr x Cu 0.4−x and Ce 0.7 Zr x Cu 0.3−x samples gradually increased with the Cu content. It was found that the Ce 0.7 Zr 0.2 Cu 0.1 sample owned the most abundant oxygen vacancies on the surface. The Ce x Zr y Cu 1−x−y mixed oxides with lower Cu content (≤0.1) produced higher amount of H 2 and CO while smaller CO 2 . Ce 0.7 Zr 0.2 Cu 0.1 sample still retained better structural stability and thermal stability after 20 times cycled reaction.
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Catalysts
·
2019
·Vol. 9
·期 3
·218
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IF 3.444
Shaoxia Guo,Guilong Liu,Tong Han,Ziyang Zhang,Yuan Liu
Owing to the outstanding catalytic performance for higher alcohol synthesis, Ga-Co catalysts have attracted much attention. In view of their unsatisfactory stability and alcohol selectivity, herein, K-modulated Co nanoparticles trapped in La-Ga-O catalysts were prepared by the reduction of La1−xKxCo0.65Ga0.35O3perovskite precursor. Benefiting from the atomic dispersion of all the elements in the precursor, during the reduction of La1−xKxCo0.65Ga0.35O3, Co nanoparticles could be confined into the K-modified La-Ga-O composite oxides, and the confinement of La-Ga-O could improve the anti-sintering performance of Co nanoparticles. In addition, the addition of K modulated parts of La-Ga-O into La2O3, which ameliorated the anti-carbon deposition performance. Finally, the addition of K increased the dispersion of cobalt and provided more electron donors to metallic Co, resulting in a high activity and superior selectivity to higher alcohols. Benefiting from the above characteristics, the catalyst possesses excellent activity, good selectivity, and superior stability.Keywords:perovskite-type oxide (PTO);cobalt;gallium;potassium;higher alcohols;syngas
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JOURNAL OF SOLID STATE CHEMISTRY
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2018
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IF 2.179
Shi-Yuan Zhang,Yuan-Yuan Yang,Yue-Qing Zheng,Hong-Lin Zhu
Electrocatalytic reduction of CO 2 to useful fuels or chemicals is a promising path for carbon recycling. In this study, a novel mixed-metallic MOF [Ag 4 Co 2 (pyz)PDC 4 ][Ag 2 Co(pyz) 2 PDC 2 ] was synthesized, and it transformed into Ag doped Co 3 O 4 catalyst, which exhibits excellent electro-catalytic performance for reduction of CO 2 in water to syngas (H 2 + CO). The as-prepared Ag/Co 3 O 4 material exhibits a high selectivity of CO in 0.1 M KHCO 3 aqueous solution (CO 2 saturated) with the corresponding faradaic efficiency up to 55.6%. Compared with the Ag/Co 3 O 4 electrode, the maximum faradaic efficiency (FE) of CO of pure Co 3 O 4 is 21.3% at − 1.8 V vs. SCE. The results show that the presence of Ag can improve the efficiency of CO significantly, thereby inhibiting the production of H 2 . The stability of the samples can be maintained for more than 10 h at − 1.8 V vs. SCE. The ratio of production between H 2 and CO can be controlled by varying the potential values.
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FUEL
·
2024
·
IF 6.7
Juzhi Leng,Xinru Yang,Qi Zeng,Wenting Chen,Shupeng Guo,Min Zhong,Lili Liu,Yunlei Chen,Pengju Yang,Mingqi Li
Photochemical reduction of CO 2 (CO 2 RR) to syngas is an attractive approach for carbon–neutral recycling. Manipulating binding strength to reactive species on catalyst surfaces is challenging but essential for achieving efficient syngas production with a desired CO/H 2 ratio. Here, we demonstrate that the binding strength to key reaction intermediates (*CO 2 , *H and *CO) on the Co 3 O 4 surface can be fine-tuned by incorporating varying amount of Zn atoms. Dedicated experiments and theoretical simulations unveil that Zn doping allows for simultaneous control of both CO 2 adsorption/activation and the adsorption affinity of *CO on Zn-Co 3 O 4 catalysts, resulting in a significant enhancement in CO 2 to CO conversion. Moreover, Zn doping can alter the hydrophilicity of the catalyst surface, affecting the water adsorption behavior and adjusting the hydrogen evolution reaction (HER) activity. As a result, the CO/H 2 ratio can be readily tuned via varying the Zn doping level. This study presents an effective and economical method approach to manipulate the electronic structure of catalyst surfaces for controlling the kinetics of CO 2 RR and HER reactions, providing valuable insight into the design of highly active transition metal oxides (TMOs) based photocatalysts for syngas production with a tailored CO/H 2 ratio.
研究领域:
材料科学
·
化学工程
·
环境科学
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高影响因子
Nano Research
·
2021
·Vol. 15
·期 1
·528-534
·
IF 8.897
Shen Chenqi,Wang Pengtang,Li Leigang,Huang Xiaoqing,Shao Qi
Syngas (CO + H 2 ) is the incredibly important feedstock for producing synthetic fuels and various value-added chemicals. CO 2 electrochemical reduction to syngas is an environmental-friendly and sustainable approach, but still challenging to produce tunable syngas with a wide ratio of CO/H 2 . Herein, by modulating the structure and phase, we have successfully obtained a series of copper-indium (Cu-In) catalysts, which are efficient for producing syngas with tunable CO/H 2 ratios. A series of CuIn bimetallic catalysts with different structures from hollow sphere to two-layer hollow sphere and different phases from CuO to Cu 2 O are developed. We find that the CO and H 2 are the only gaseous products, in which the CO/H 2 ratios can be readily tuned from 1.2 ± 0.1 to 9.0 ± 1.5 by simply controlling the thermal annealing temperature. It also exhibits high durability during a 10-h test. The unique performance is attributed to the modulated In enrichment on the Cu surfaces during the CO 2 reduction reaction, which causes the differences in binding energies for key reaction intermediates, thus resulting in the tunable composition of syngas. The present work emphasizes a simple yet efficient phase and structure modulating strategy for designing potential electrocatalysts for producing syngas with widely tunable CO/H 2 ratios.
研究领域:
材料科学
·
能源化学
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Xiaodan Zhang,Fei Yu,Jie Zhang,Zhiyong Tang,Yuhan Sun
Wall-coating is an attractive approach for immobilizing catalyst into microchannels due to potential enhancement in heat and mass transfer and a small pressure drop. A novel hybrid method was thus developed for efficiently wall-coating special cobalt carbide catalyst into FeCrAlloy microchannels on the direct production of lower olefins from syngas. The effect of pretreatment was investigated to form a uniform Al2O3 layer on the surface of FeCrAlloy substrate. The small loss of coated catalyst layer in the mechanical adherence test by exposing the FeCrAlloy substrate to a fast nitrogen flow indicated its outstanding stability in the immobilization of cobalt carbide catalyst. The coating catalyst exhibited a stable and good activity after reaching the steady state. Additionally, calculations revealed that the wall-coated and fixed-bed microreactors had comparable mass transfer factor jD, but the former provided a five times larger heat transfer factor jH and 100 times lower pressure drop per unit length, confirming in detail the advantages of wall-coating. The proposed wall-coating strategy can be applied for immobilizing other catalyst within metallic microchannels, providing a practical technical solution for industrial implementation of microreactors.
研究领域:
化学工程
·
催化材料
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危险品化学品经营许可证（带存储）