Dong Ye , Jingyi Feng , Jiahui Liu , Kai Zhu , Xiaoxiang Wang , Ruitang Guo
{"title":"用改性WO3催化NH3燃烧,平衡CeOx-CrOx混合氧化物催化剂的酸性和氧化性","authors":"Dong Ye , Jingyi Feng , Jiahui Liu , Kai Zhu , Xiaoxiang Wang , Ruitang Guo","doi":"10.1016/j.fuel.2025.136315","DOIUrl":null,"url":null,"abstract":"<div><div>This article provides a comprehensive analysis of the impact of WO<sub>3</sub> incorporation on the NH<sub>3</sub> catalytic combustion performance of CeO<em><sub>x</sub></em>-CrO<em><sub>x</sub></em> catalysts. The addition of WO<sub>3</sub> was observed to decrease NH<sub>3</sub> oxidation efficiency while enhancing N<sub>2</sub> selectivity, with T<sub>90</sub> and N<sub>2</sub> selectivity (at 350 °C) increasing from approximately 239 °C and 60 % to around 290 °C and 92 %, respectively. Characterization studies revealed that the introduction of WO<sub>3</sub> reduced both the quantity and reactivity of Cr<sup>6+</sup> and surface oxygen species, thereby inhibiting the over-oxidation of NH<sub>3</sub> to NO<em><sub>x</sub></em> and consequently boosting N<sub>2</sub> selectivity. Additionally, the WO<sub>3</sub>-modified catalysts developed abundant acid sites, ensuring adequate NH<sub>3</sub> adsorption and partially offsetting the adverse effects of the reduced NH<sub>3</sub> activation. This explains the marginal increase in T<sub>90</sub> for the catalysts with W/(Cr + Ce) molar ratios of 0.2, 0.4, and 0.8. However, excessive WO<sub>3</sub> loading led to the over-adsorption of NH<sub>3</sub>, which interfered with its activation and over-oxidation due to electronic interactions or the obstruction of redox sites. Coupled with a progressively weakened oxidative capacity, these factors significantly hindered NH<sub>3</sub> catalytic combustion reactions and further elevated N<sub>2</sub> selectivity. Therefore, it is concluded that the balance of the catalysts’ acidic and redox properties is crucial for achieving both high NH<sub>3</sub> oxidation efficiency and N<sub>2</sub> selectivity.</div></div>","PeriodicalId":325,"journal":{"name":"Fuel","volume":"404 ","pages":"Article 136315"},"PeriodicalIF":7.5000,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Balance on the acidity and oxidizability of the CeOx-CrOx mixed oxide catalyst by modifying WO3 for the catalytic combustion of NH3\",\"authors\":\"Dong Ye , Jingyi Feng , Jiahui Liu , Kai Zhu , Xiaoxiang Wang , Ruitang Guo\",\"doi\":\"10.1016/j.fuel.2025.136315\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>This article provides a comprehensive analysis of the impact of WO<sub>3</sub> incorporation on the NH<sub>3</sub> catalytic combustion performance of CeO<em><sub>x</sub></em>-CrO<em><sub>x</sub></em> catalysts. The addition of WO<sub>3</sub> was observed to decrease NH<sub>3</sub> oxidation efficiency while enhancing N<sub>2</sub> selectivity, with T<sub>90</sub> and N<sub>2</sub> selectivity (at 350 °C) increasing from approximately 239 °C and 60 % to around 290 °C and 92 %, respectively. Characterization studies revealed that the introduction of WO<sub>3</sub> reduced both the quantity and reactivity of Cr<sup>6+</sup> and surface oxygen species, thereby inhibiting the over-oxidation of NH<sub>3</sub> to NO<em><sub>x</sub></em> and consequently boosting N<sub>2</sub> selectivity. Additionally, the WO<sub>3</sub>-modified catalysts developed abundant acid sites, ensuring adequate NH<sub>3</sub> adsorption and partially offsetting the adverse effects of the reduced NH<sub>3</sub> activation. This explains the marginal increase in T<sub>90</sub> for the catalysts with W/(Cr + Ce) molar ratios of 0.2, 0.4, and 0.8. However, excessive WO<sub>3</sub> loading led to the over-adsorption of NH<sub>3</sub>, which interfered with its activation and over-oxidation due to electronic interactions or the obstruction of redox sites. Coupled with a progressively weakened oxidative capacity, these factors significantly hindered NH<sub>3</sub> catalytic combustion reactions and further elevated N<sub>2</sub> selectivity. Therefore, it is concluded that the balance of the catalysts’ acidic and redox properties is crucial for achieving both high NH<sub>3</sub> oxidation efficiency and N<sub>2</sub> selectivity.</div></div>\",\"PeriodicalId\":325,\"journal\":{\"name\":\"Fuel\",\"volume\":\"404 \",\"pages\":\"Article 136315\"},\"PeriodicalIF\":7.5000,\"publicationDate\":\"2025-07-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Fuel\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S001623612502040X\",\"RegionNum\":1,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENERGY & FUELS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Fuel","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S001623612502040X","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
Balance on the acidity and oxidizability of the CeOx-CrOx mixed oxide catalyst by modifying WO3 for the catalytic combustion of NH3
This article provides a comprehensive analysis of the impact of WO3 incorporation on the NH3 catalytic combustion performance of CeOx-CrOx catalysts. The addition of WO3 was observed to decrease NH3 oxidation efficiency while enhancing N2 selectivity, with T90 and N2 selectivity (at 350 °C) increasing from approximately 239 °C and 60 % to around 290 °C and 92 %, respectively. Characterization studies revealed that the introduction of WO3 reduced both the quantity and reactivity of Cr6+ and surface oxygen species, thereby inhibiting the over-oxidation of NH3 to NOx and consequently boosting N2 selectivity. Additionally, the WO3-modified catalysts developed abundant acid sites, ensuring adequate NH3 adsorption and partially offsetting the adverse effects of the reduced NH3 activation. This explains the marginal increase in T90 for the catalysts with W/(Cr + Ce) molar ratios of 0.2, 0.4, and 0.8. However, excessive WO3 loading led to the over-adsorption of NH3, which interfered with its activation and over-oxidation due to electronic interactions or the obstruction of redox sites. Coupled with a progressively weakened oxidative capacity, these factors significantly hindered NH3 catalytic combustion reactions and further elevated N2 selectivity. Therefore, it is concluded that the balance of the catalysts’ acidic and redox properties is crucial for achieving both high NH3 oxidation efficiency and N2 selectivity.
期刊介绍:
The exploration of energy sources remains a critical matter of study. For the past nine decades, fuel has consistently held the forefront in primary research efforts within the field of energy science. This area of investigation encompasses a wide range of subjects, with a particular emphasis on emerging concerns like environmental factors and pollution.