المؤلفون: Wu, Peng¹ (AUTHOR), Shen, Kai^1,2 (AUTHOR), Wang, Bingran¹ (AUTHOR), Ding, Shipeng¹ (AUTHOR), Zhang, Shule³ (AUTHOR), Zhang, Yaping¹ (AUTHOR) amflora@seu.edu.cn

المصدر: Separation & Purification Technology. Aug2024, Vol. 341, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *CRYSTAL surfaces, *ALUMINUM oxide, *NANORODS, *CATALYST poisoning, *ADSORPTION capacity, *ACTIVATION energy, *CESIUM

مستخلص: The modulation of surface morphology and exposed crystal planes contributed to the inhibition of HCl adsorption on the catalyst surface, which in turn facilitated higher hydrolytic stability. [Display omitted] • H-K 0.1 Al 2 O 3 catalyst exhibited excellent hydrolysis activity and chlorine resistance. • The enhanced catalytic performance was related to the basicity and adsorption ability. • Hydrolysis reaction pathways of COS and CS 2 were cleared by DFT calculations. • Diminished HCl adsorption and altered adsorption sites contribute to catalyst stability. The undesirable stability and vulnerability to poisoning of catalysts have posed a great obstacle to the development of organosulfur hydrolysis technology. In this paper, H-K 0.1 Al 2 O 3 nanorod catalysts with exposed Al 2 O 3 (1 1 1) crystal plane were prepared by hydrothermal synthesis. The results indicated that the COS and CS 2 hydrolysis activity at low temperatures of the H-K 0.1 Al 2 O 3 catalyst was significantly higher than that of K 0.1 Al 2 O 3. In the presence of 0.01 vol% HCl, there was no decrease in the COS conversion of H-K 0.1 Al 2 O 3 after 12 h of reaction. The CS 2 conversion was stable at about 65 %. Characterization results revealed that the improved hydrolysis performance was mainly related to enhanced surface alkalinity and more oxygen vacancies, which strengthened the adsorption capacity of the reactive molecules. The results of DFT calculations proved the stronger adsorption ability of the Al 2 O 3 (1 1 1) plane than the Al 2 O 3 (1 1 0) plane. The suppressed HCl adsorption contributed to the enhanced resistance to chlorine poisoning. Reaction path calculations demonstrated that the H 2 O molecules on the Al 2 O 3 (1 1 1) dissociated more rapidly to produce –OH, and the intermediates -CS 2 OH and -HSCO were more easily generated with lower reaction energy barriers. [ABSTRACT FROM AUTHOR]

المؤلفون: Wu, Peng, Ding, Shipeng, Wang, Bingran, Shen, Kai, Zhang, Shule, Zhang, Yaping

المصدر: Journal of Environmental Chemical Engineering; Apr2024, Vol. 12 Issue 2, pN.PAG-N.PAG, 1p

مصطلحات موضوعية: ALUMINUM oxide, NITROGEN, ACTIVATION energy, CATALYSTS, GAS furnaces, SCISSION (Chemistry)

مستخلص: The simultaneous catalytic purification of COS and CS 2 in blast furnace gas usually suffers from poor removal activity, and a molecular understanding of the reaction mechanism over typical Al-based catalysts is still missing. Herein, we reported that N-doping was an effective strategy to enhance the activity of K 0.1 Al 2 O 3. The optimal N-doped K 0.1 Al 2 O 3 achieved more than 95% COS and CS 2 conversion, with 80% H 2 S selectivity at 150 °C. It was revealed that N-modification promoted the formation of N-Al, oxygen vacancies and OH- species, and induced stronger basic sites. Besides, the N-doping enhanced COS and CS 2 adsorption, and facilitated the formation of reactive intermediate species. The adsorbed CS 2 combines with H to produce CS 2 H-, which further reacts with H- or OH- and triggers the cleavage of the C-S bond to produce H 2 S and COS. The introduction of N changes the process of C-S bond cleavage and reduces the reaction energy barrier. • N-doping strategy was applied to enhance the activity of K 0.1 Al 2 O 3 catalysts. • The preferred catalyst exhibits significantly enhanced simultaneous removal of COS and CS 2. • The reaction pathways on the surfaces of catalysts were proposed at the molecular level. • The introduction of N alters the process of C-S bond cleavage with lower energy barrier. [ABSTRACT FROM AUTHOR]

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المؤلفون: Wu, Peng¹ (AUTHOR), Zhang, Yaping¹ (AUTHOR) amflora@seu.edu.cn, Xu, Yun² (AUTHOR), Wang, Bingran¹ (AUTHOR), Shen, Kai¹ (AUTHOR), Zhuang, Ke^1,2 (AUTHOR) ke.zhuang@ceic.com, Wang, Sheng² (AUTHOR), Zhang, Shule³ (AUTHOR), Ding, Shipeng¹ (AUTHOR)

المصدر: Fuel. May2024, Vol. 363, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *ALUMINUM oxide, *CATALYST poisoning, *CATALYSTS, *ACTIVATION energy, *HYDROLYSIS, *POISONING

مستخلص: The doping of N inhibited the adsorption of HCl on the Al sites and avoided the chlorination of Al 2 O 3 , which in turn enhanced the resistance of the catalyst to chlorine poisoning. [Display omitted] • N-doped catalysts exhibited significantly boosted hydrolysis activity and stability. • The disrupted basicity and adsorption capacity triggered the catalyst deactivation. • Enhanced catalyst resistance was associated with inhibition of Al site acidification. • The reaction energy barrier of HCl dissociation was increased after doping N. The presence of HCl in blast furnace gas significantly inhibits hydrolytic activity and catalyst stability. The anti-chlorine capacity and poisoning mechanism of Al 2 O 3 catalysts before and after nitrogen modification was investigated by activity evaluation, characterization analysis and theoretical calculations. In the presence of 0.01 vol% HCl, the COS and CS 2 conversions of K 0.1 Al 2 O 3 catalysts decreased rapidly after 4 h of reaction, which was amended by N doping. The N 0.1 K 0.1 Al 2 O 3 catalyst maintained 48.23 % COS conversion and 45.41 % CS 2 conversion, respectively, after 16 h reaction. The deteriorated reactivity was mainly associated with the decreased specific surface area, reduced chemisorbed oxygen, disrupted basicity and COS and CS 2 adsorption ability. Sulfate and HCl on the surface of the unmodified catalyst mainly destroyed the Al sites and led to catalyst deactivation. N doping reinforced the tendency of toxic molecules to adsorb at the K site (K 2 SO 4 and KCl) and thus protected the Al active site. DFT calculation results demonstrated the inhibition of HCl adsorption at the Al site by N modification, while the trapping of HCl by both K and N sites efficiently protected the Al site from acidification. The reaction pathway calculations certified that N doping increased the energy barrier of the HCl dissociation reaction, which inhibited the acidification and deactivation of Al 2 O 3 to some extent. [ABSTRACT FROM AUTHOR]