Metal-Free Phosphated Mesoporous SiO<sub>2</sub> as Catalyst for the Low-Temperature Conversion of SO<sub>2</sub> to H<sub>2</sub>S in Hydrogen
Highly active metal-free mesoporous phosphated silica was synthesized by a two-step process and used as a SO<sub>2</sub> hydrogenation catalyst. With the assistance of a microwave, MCM-41 was obtained within a 10 min heating process at 180 °C, then a low ratio of P precursor was incorpor...
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MDPI AG
2021-09-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/11/9/2440 |
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| author | Xinnan Lu Safa Gaber Mark A. Baker Steven J. Hinder Kyriaki Polychronopoulou |
| author_facet | Xinnan Lu Safa Gaber Mark A. Baker Steven J. Hinder Kyriaki Polychronopoulou |
| author_sort | Xinnan Lu |
| collection | DOAJ |
| description | Highly active metal-free mesoporous phosphated silica was synthesized by a two-step process and used as a SO<sub>2</sub> hydrogenation catalyst. With the assistance of a microwave, MCM-41 was obtained within a 10 min heating process at 180 °C, then a low ratio of P precursor was incorporated into the mesoporous silica matrix by a phosphorization step, which was accomplished in oleylamine with trioctylphosphine at 350 °C for 2 h. For benchmarking, the SiO<sub>2</sub> sample without P precursor insertion and the sample with P precursor insertion into the calcined SiO<sub>2</sub> were also prepared. From the microstructural analysis, it was found that the presence of CTAB surfactant was important for the incorporation of active P species, thus forming a highly dispersed, ultrafine (uf) phosphate silica, (Si-P) catalyst. The above approach led to the promising catalytic performance of uf-P@meso-SiO<sub>2</sub> in the selective hydrogenation of SO<sub>2</sub> to H<sub>2</sub>S; the latter reaction is very important in sulfur-containing gas purification. In particular, uf-P@meso-SiO<sub>2</sub> exhibited activity at the temperature range between 150 and 280 °C, especially SO<sub>2</sub> conversion of 94% and H<sub>2</sub>S selectivity of 52% at 220 °C. The importance of the CTAB surfactant can be found in stabilizing the high dispersion of ultrafine P-related species (phosphates). Intrinsic characteristics of the materials were studied using XRD, FTIR, EDX, N<sub>2</sub> adsorption/desorption, TEM, and XPS to reveal the structure of the above catalysts. |
| first_indexed | 2024-03-10T07:21:53Z |
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| language | English |
| last_indexed | 2024-03-10T07:21:53Z |
| publishDate | 2021-09-01 |
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| series | Nanomaterials |
| spelling | doaj.art-1c1ed75188f4400799dcadcb8b5ae73f2023-11-22T14:32:36ZengMDPI AGNanomaterials2079-49912021-09-01119244010.3390/nano11092440Metal-Free Phosphated Mesoporous SiO<sub>2</sub> as Catalyst for the Low-Temperature Conversion of SO<sub>2</sub> to H<sub>2</sub>S in HydrogenXinnan Lu0Safa Gaber1Mark A. Baker2Steven J. Hinder3Kyriaki Polychronopoulou4Department of Chemical Engineering, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab EmiratesDepartment of Mechanical Engineering, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab EmiratesThe Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UKThe Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UKDepartment of Mechanical Engineering, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab EmiratesHighly active metal-free mesoporous phosphated silica was synthesized by a two-step process and used as a SO<sub>2</sub> hydrogenation catalyst. With the assistance of a microwave, MCM-41 was obtained within a 10 min heating process at 180 °C, then a low ratio of P precursor was incorporated into the mesoporous silica matrix by a phosphorization step, which was accomplished in oleylamine with trioctylphosphine at 350 °C for 2 h. For benchmarking, the SiO<sub>2</sub> sample without P precursor insertion and the sample with P precursor insertion into the calcined SiO<sub>2</sub> were also prepared. From the microstructural analysis, it was found that the presence of CTAB surfactant was important for the incorporation of active P species, thus forming a highly dispersed, ultrafine (uf) phosphate silica, (Si-P) catalyst. The above approach led to the promising catalytic performance of uf-P@meso-SiO<sub>2</sub> in the selective hydrogenation of SO<sub>2</sub> to H<sub>2</sub>S; the latter reaction is very important in sulfur-containing gas purification. In particular, uf-P@meso-SiO<sub>2</sub> exhibited activity at the temperature range between 150 and 280 °C, especially SO<sub>2</sub> conversion of 94% and H<sub>2</sub>S selectivity of 52% at 220 °C. The importance of the CTAB surfactant can be found in stabilizing the high dispersion of ultrafine P-related species (phosphates). Intrinsic characteristics of the materials were studied using XRD, FTIR, EDX, N<sub>2</sub> adsorption/desorption, TEM, and XPS to reveal the structure of the above catalysts.https://www.mdpi.com/2079-4991/11/9/2440metal-freeSi-P catalystSO<sub>2</sub> hydrogenationH<sub>2</sub>Smicrowave synthesis |
| spellingShingle | Xinnan Lu Safa Gaber Mark A. Baker Steven J. Hinder Kyriaki Polychronopoulou Metal-Free Phosphated Mesoporous SiO<sub>2</sub> as Catalyst for the Low-Temperature Conversion of SO<sub>2</sub> to H<sub>2</sub>S in Hydrogen Nanomaterials metal-free Si-P catalyst SO<sub>2</sub> hydrogenation H<sub>2</sub>S microwave synthesis |
| title | Metal-Free Phosphated Mesoporous SiO<sub>2</sub> as Catalyst for the Low-Temperature Conversion of SO<sub>2</sub> to H<sub>2</sub>S in Hydrogen |
| title_full | Metal-Free Phosphated Mesoporous SiO<sub>2</sub> as Catalyst for the Low-Temperature Conversion of SO<sub>2</sub> to H<sub>2</sub>S in Hydrogen |
| title_fullStr | Metal-Free Phosphated Mesoporous SiO<sub>2</sub> as Catalyst for the Low-Temperature Conversion of SO<sub>2</sub> to H<sub>2</sub>S in Hydrogen |
| title_full_unstemmed | Metal-Free Phosphated Mesoporous SiO<sub>2</sub> as Catalyst for the Low-Temperature Conversion of SO<sub>2</sub> to H<sub>2</sub>S in Hydrogen |
| title_short | Metal-Free Phosphated Mesoporous SiO<sub>2</sub> as Catalyst for the Low-Temperature Conversion of SO<sub>2</sub> to H<sub>2</sub>S in Hydrogen |
| title_sort | metal free phosphated mesoporous sio sub 2 sub as catalyst for the low temperature conversion of so sub 2 sub to h sub 2 sub s in hydrogen |
| topic | metal-free Si-P catalyst SO<sub>2</sub> hydrogenation H<sub>2</sub>S microwave synthesis |
| url | https://www.mdpi.com/2079-4991/11/9/2440 |
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