CHEMICAL ENGINEERING SCIENCE
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2023
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IF 4.7
Xia Zhang,Haibo Wang,Lianke Gou,Lanpeng Li,Aijun Duan,Zhengkai Cao
Serial VPO catalysts with different crystal structures were prepared by adjusting the ratios of air and N 2 in the calcination process. The precursors and vanadium phosphorus oxide (VPO) catalysts were characterized by various measurements. As the air and N 2 ratios were lower than 1:1, the ordered VOHPO 4 ·0.5H 2 O phase was mainly formed in the precursors during calcination. However, as the ratio of air to N 2 reached 3:1, amorphous VOPO 4 phases were formed over the surface of the precursor during calcination, which prevented the formation of ordered V5+ species over the surface of the VPO catalyst after activation. Meanwhile, a high proportion of VOHPO 4 ·0.5H 2 O in the precursor could facilitate more formation of the ordered α 1 -VOPO 4 phase over the surface of the VPO catalyst. Interestingly, the crystal structure over the surface of active VPO catalysts was totally different from the core of VPO catalysts. There were more P species and V species with 5+ existing over the surface of the VPO catalysts. The evaluation results of n-butane oxidation showed that when the ratio of air to N 2 was 1:3, the corresponding VPO-1A catalyst presented the highest conversion of n-butane and yield of the MA product (57.6 m% at 412 °C). The reason should be related to the fact that the VPO-1A catalyst possessed the highest acidity and proportions of surface V5+ species and Sur-O species. As the ratio of air to N 2 reached 3:1, the VPO-3A catalyst showed the poorest performance in the oxidation of n-butane, which could be due to the formation of inactive and amorphous VOPO 4 phases over the surface of the VPO catalyst. Finally, kinetic and thermodynamic models were established and calculated to investigate the characteristics of n-butane oxidation reactions for various VPO 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
CATALYSIS LETTERS
·
2022
·Vol. 153
·期 1
·271-284
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IF 2.936
Faizan Muhammad,Zhang Ruirui,Liu Ruixia
Recently, global warming is proving to be an increasing challenge for the sustainable human survival on planet earth. Worldwide, researchers are putting their efforts into controlling carbon emissions and have set the aim to achieve levels of overall carbon neutrality. Different industrial processes, especially oil refinery processes, release large amounts of low-carbon alkanes as gaseous byproducts directly into the air and pollute clean environments, which is one of the major reasons for sudden climate changes, ocean acidification, loss of biodiversity, and rising sea levels. The conversion of lighter alkanes, especially n-butane, into value-added chemicals can be beneficial for green economies and green environments. Presently, heterogeneous vanadium phosphorus oxide catalysts (VPOs) are considered potential candidates for n-butane selective oxidation toward maleic anhydride (MA). In this research, we developed a VPO catalyst with the assistance of copper-based ionic liquids (Cu-ILs), including [Bmim][OAc]–[Cu(OAc) 2 ], [Bmim][Cl]–[CuCl], and [Bmim][Cl]–[CuCl 2 ]. We observed significant improvement in the MA selectivity; meanwhile, the CO x (CO and CO 2 ) selectivity was decreased. Compared to the unpromoted catalyst (Blank-VPO), the Cu-IL-promoted catalyst, i.e., [Bmim][Cl]–[CuCl 2 ]-VPO remarkably increased the MA selectivity (11%) and n-butane conversion (9.2%) and minimized the CO x selectivity (11%). In addition to this the ratio of CO/CO 2 has been reduced from 2.01 to 1.32. Therefore, this can be a helpful process for achieving carbon neutrality goals. Graphical Abstract
研究领域:
化学工程
·
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2022
·
IF 6.76
Muhammad Faizan,Hao Li,Yumei Liu,Kexin Li,Shuang Wei,Ruirui Zhang,Ruixia Liu
Currently, deep eutectic solvents (DESs), as an exclusive class of ionic liquid analogs, are extensively employed in various fields. Herein, vanadium phosphorus oxide (VPO) catalysts assisted by copper-based deep eutectic solvent (Cu-DES) as an electronic promoter and structure directing agent were ingeniously synthesized and exploited in the selective oxidation of n-butane to maleic anhydride (MA). The DES is efficient, cost effective and highly green compared to conventionally use metal inorganic modifiers. Cu-DES was prepared from a eutectic mixture of an organic salt (ChCl) and a metal salt hydrate/metal salt of cupric (Cu(NO 3 ) 2 .3H 2 O, CuCl 2 ) and cuprous (CuCl) salt with a molar ratio of 1:1–1:3, which notably improved the catalytic performance compared to that of an unpromoted VPO catalyst. The MA selectivity and n-butane conversion of Cu–DES–VPO increased significantly, while the CO x (CO and CO 2 ) selectivity decreased. FTIR, DSC , XRD, SEM, EDS, TEM, Raman, TGA, XPS, and NH 3 -TPD characterization techniques were utilized to fully analyze the DES, precursor and catalyst to explore MA selectivity. This work shifts the significant increase of 13% n-butane conversion, 11% MA selectivity and 16% MA mass yield, which greatly influences low carbon alkane utilization. Importantly, the CO: CO 2 ratio is reduced from 2.02 to 1.62, which is more beneficial for chemical plants as well as green environments.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
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