CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Rosine Ahishakiye,Fumin Wang,Xubin Zhang,Mingshuai Sun,Yi Zhai,Yongkui Liu,Yuzhou Wu,Mengyue Li,Mengyao Li,Qing Zhang
The efficient production of the liquid fuel 2,5-dimethylfuran (DMF) from biomass-derived 5-hydroxymethylfurfural (HMF) is very complicated because of the presence of the aldehyde group, hydroxyl group, and C C bond. In this study, a novel Co-CoOx –FeNiCo/γ-Al 2 O 3 catalyst was developed for selective hydrogenation of HMF to DMF. The catalyst was characterized by using XRD, TEM , SAED , BET, XPS, NH 3 -TPD, and H 2 -TPR techniques. The catalyst reduced at 500 °C exhibited excellent catalytic performance and the highest DMF yield (>99.9%) was obtained at 190 °C and 4 h. During the reaction, metal sites selectively hydrogenated the C O bond while acid sites (CoOx acid sites) selectively hydrogenolyzed C O bond. Appropriate surface acidity of the catalyst and the balance between metal and metal oxide species are the main factors for achieving a high yield of DMF. At reaction temperatures below 150 °C, DMF was not produced and HMF has completely converted into 2,5-Bis(hydroxymethyl)furan (BHMF), an important furan diol for polymers production. 100% BHMF yield was also obtained for the HMF hydrogenation over 300 °C reduced catalysts due to the high concentration of strong acid sites. The catalyst recyclability exhibited excellent stability and the original activity was maintained after six reuses. A reaction mechanism was also proposed.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Yajing Cai,Guojie Zhang,Jun Liu,Yunfei Zhang,Tianshan Li,Xiaodi Zhang,Ying Wang,Yuqiong Zhao,Guoqiang Li
Dry reforming of methane (DRM) is an effective method for achieving carbon reduction and carbon neutrality by directly converting two greenhouse gases , CH 4 and CO 2 , into value-added products. However, catalysts used in this process are prone to metal sintering and carbon deposition , which are major obstacles. Thus, the design of high-performance catalysts is crucial for the success of dry reforming technology. In this paper, a series of Co-based catalysts modified with different rare earth metals (Y, Tb, Gd) and γ-Al 2 O 3 as the support were prepared using the conventional co-impregnation method. The effects of the introduction of rare earth metals additives on the activity and resistance to carbon build-up of the catalysts were investigated. The catalysts were analyzed using various characterization techniques. The results showed that Y and Tb as additives could effectively improve the activity and stability of the catalyst. However, the Gd modified Co-based catalyst had a large specific surface area but was less favorable for the DRM reaction. The best performance catalyst was achieved with the 10Co–5Y/γ-Al 2 O 3 under 750 °C with CH 4 and CO 2 conversions of 91.79% and 98.33%, respectively. This is mainly due to the fact that the introduction of Y enhances the electron transfer between Co and metal oxides , generating more oxygen vacancies and base vacancies on the surface, thus enhancing the adsorption and activation of CO 2 . The 10Co–5Y/γ-Al 2 O 3 catalyst demonstrated excellent DRM performance even after 20 h at 750 °C. Moreover, we proposed a hypothesis regarding the mechanism of resistance to carbon build-up. This study provides a reasonable idea to design Co-based catalysts with resistance to sintering and carbon accumulation to improve the performance of reforming catalysts.
研究领域:
催化
·
化学工程
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2016
·
IF 3.958
Huan Chen,Ting Li,Fang Jiang,Zhe Wang
Catalytic reduction of N -nitrosodimethylamine (NDMA) was investigated over γ-Al 2 O 3 supported bimetallic Pd-Ni catalysts (3%(Pd x Ni 1−x )). NDMA could be reduced to dimethylamine over 3%(Pd 0.8 Ni 0.2 ) with a metal-loading-normalized pseudo-first-order rate constant of 836 ± 21 L g me −1 h −1 . Characterization results showed that the reducibility of PdO (or NiO) was improved by addition of Ni (or Pd) in 3%(Pd x Ni 1−x ); Pd-Ni ensembles were formed in 3%(Pd x Ni 1−x ) and there was an electronic transfer from Pd to Ni; metal dispersion was affected by the formation of Pd-Ni ensembles and a volcano curve of metal dispersion via Pd/Ni ratio was observed. The activity profiles demonstrated that TOF had a significant positive relationship with metal dispersion of 3%(Pd x Ni 1−x ), indicating high metal dispersion favor NDMA reduction. NDMA reduction over 3%(Pd 0.8 Ni 0.2 ) catalyst could be described by Langmuir-Hinshelwood model, reflecting an adsorption controlled reduction mechanism. The reduction mechanism of NDMA over 3%(Pd 0.8 Ni 0.2 ) catalyst was proposed to be that H 2 was activated by Pd, and H spillover from Pd to Ni/NiO reduced NDMA though N-N cleavage.
研究领域:
环境科学
·
化学工程
·
催化
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Xinglin Wen,Yonglu Yang,Yong Pan,Jitao Hu,Xiaoyue Wan,Yanhui Yang,Sébastien Leveneur,Juncheng Jiang
The hydrogenation of 2,4-dinitrotoluene (2,4-DNT) into 1-methyl-2,4-cyclohexanediamine (2,4-MCHD), a significant yet underutilized raw material for the synthesis of methylcyclohexane diisocyanate (HTDI) with exceptional properties, represents one of the most promising reactions for the development of diisocyanate chemical processes. In this study, we developed a highly efficient and stable heterogeneous catalytic system for the direct hydrogenation of 2,4-DNT to 2,4-MCHD using Li-modified γ-Al 2 O 3 supported Ru nanoclusters (Li-modified-Ru/γ-Al 2 O 3 ). Under mild reaction conditions, we successfully inhibited side reactions, such as deamination, achieving a selectivity exceeding 95% for 2,4-MCHD, while the conversion of 2,4-DNT surpassed 99%. Kinetic studies revealed that the hydrogenation of 2,4-DNT in this system occurs as a tandem reaction, with the hydrogenation of the benzene ring identified as the rate-determining step. Investigations into the structure–activity relationship indicated that the valence state of the Ru nanocluster, the acid-base properties of the catalyst, the modification by Li, and the synergistic effects of various elements within the catalyst are critical factors contributing to the high activity and stability of the Li-modified-Ru/γ-Al 2 O 3 catalyst for the hydrogenation of 2,4-DNT to produce 2,4-MCHD. This work represents the first example of the direct hydrogenation of dinitroaromatic compounds to yield diamino aliphatic compounds and provides a solid foundation for understanding such reaction systems.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Yongli Sun,Xiang Gao,Na Yang,Xiaowei Tantai,Xiaoming Xiao,Bin Jiang,Luhong Zhang
With the aim of simultaneously achieving synthesis and morphology control of three-dimensional (3D) hierarchical layered double hydroxide (LDH) by more efficient and environmentally friendly methods, a facile and cost-efficient double-drop coprecipitation method was creatively applied to fabricate 3D flowerlike microstructures (Al2O3-MgAl-LDHs) using γ-Al2O3 as a sacrificial template. The morphology evolution process and growth characteristics of Al2O3-MgAl-LDHs were investigated in detail, revealing that γ-Al2O3 not only provides an effective support for the crystal growth of LDH but also is involved in the LDH layer formation process through self-decomposition. More importantly, LDH morphologies can be regulated by varying the reaction conditions, such as the γ-Al2O3 concentration, Mg2+/Al3+ molar ratio, and pH. Additionally, a possible formation mechanism for 3D hierarchical flowerlike Al2O3-MgAl-LDHs was illustrated. Remarkably, owing to the high specific surface area and low/medium/high-strength basic sites, the as-obtained LDH after calcination exhibited excellent catalytic activity and reusability in the transesterification of glycerol with dimethyl carbonate.
研究领域:
材料科学
·
催化
·
化学工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）