Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics
Fe2O3-Al2O3 catalysts applied for conversion of polyolefin plastic waste into multi-walled carbon nanotubes (MWCNTs) and H2 are typically produced by impregnation, co-precipitation or sol-gel synthesis at atmospheric pressure and temperatures below 100 °C. This study utilized hydrothermal conditions...
| Main Authors: | , , , , , , |
|---|---|
| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2022
|
| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/161823 |
| _version_ | 1811677403550842880 |
|---|---|
| author | Veksha, Andrei Muhammad Zahin Mohamed Amrad Chen, Wen Qian Dara Khairunnisa Mohamed Tiwari, Satya Brat Lim, Teik-Thye Lisak, Grzegorz |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Veksha, Andrei Muhammad Zahin Mohamed Amrad Chen, Wen Qian Dara Khairunnisa Mohamed Tiwari, Satya Brat Lim, Teik-Thye Lisak, Grzegorz |
| author_sort | Veksha, Andrei |
| collection | NTU |
| description | Fe2O3-Al2O3 catalysts applied for conversion of polyolefin plastic waste into multi-walled carbon nanotubes (MWCNTs) and H2 are typically produced by impregnation, co-precipitation or sol-gel synthesis at atmospheric pressure and temperatures below 100 °C. This study utilized hydrothermal conditions and established the role of precipitating agents (urea, N-methylurea and N,N'-dimethylurea) on properties and catalytic activity of Fe2O3-Al2O3 catalysts (Fe-u, Fe-mu and Fe-dmu, respectively). The precipitating agent played a key role in tailoring the properties, such as crystallization degree, surface area and reducibility. The precipitating agents influenced the yield and outer diameters of MWCNTs but did not affect graphitization degree. Among the synthesized catalysts, Fe-u had the largest surface area and preferential formation of the highly reducible α-Fe2O3 crystalline phase. As a result, Fe-u had the highest activity during conversion of pyrolysis gas from low-density polyethylene (LDPE) into MWCNTs, yielding 0.91 g·g-1-catalyst MWCNTs at 800 °C as compared to 0.42 and 0.14 g·g-1-catalyst using Fe-dmu and Fe-mu, respectively. Fe-dmu favored the growth of MWCNTs with smaller outer diameters. Fe-u demonstrated high efficiency during operation using a continuous flow of pyrolysis gas from a mixture of polyolefins (70 wt% polypropylene, 6 wt% LDPE and 24 wt% high density polyethylene) producing 4.28 g·g-1-catalyst MWCNTs at 3.2% plastic conversion efficiency and a stable H2 flow for 155 min (25-32 vol%). The obtained data demonstrate that the selection of an appropriate precipitating agent for hydrothermal synthesis allows for the production of highly active Fe2O3-Al2O3 catalysts for the upcycling of polyolefin plastic waste into MWCNTs and H2. |
| first_indexed | 2024-10-01T02:36:49Z |
| format | Journal Article |
| id | ntu-10356/161823 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T02:36:49Z |
| publishDate | 2022 |
| record_format | dspace |
| spelling | ntu-10356/1618232022-09-21T01:53:15Z Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics Veksha, Andrei Muhammad Zahin Mohamed Amrad Chen, Wen Qian Dara Khairunnisa Mohamed Tiwari, Satya Brat Lim, Teik-Thye Lisak, Grzegorz School of Civil and Environmental Engineering Nanyang Environment and Water Research Institute Residues and Resource Reclamation Centre Engineering::Environmental engineering Hydrothermal Synthesis Multi-walled Carbon Nanotubes Fe2O3-Al2O3 catalysts applied for conversion of polyolefin plastic waste into multi-walled carbon nanotubes (MWCNTs) and H2 are typically produced by impregnation, co-precipitation or sol-gel synthesis at atmospheric pressure and temperatures below 100 °C. This study utilized hydrothermal conditions and established the role of precipitating agents (urea, N-methylurea and N,N'-dimethylurea) on properties and catalytic activity of Fe2O3-Al2O3 catalysts (Fe-u, Fe-mu and Fe-dmu, respectively). The precipitating agent played a key role in tailoring the properties, such as crystallization degree, surface area and reducibility. The precipitating agents influenced the yield and outer diameters of MWCNTs but did not affect graphitization degree. Among the synthesized catalysts, Fe-u had the largest surface area and preferential formation of the highly reducible α-Fe2O3 crystalline phase. As a result, Fe-u had the highest activity during conversion of pyrolysis gas from low-density polyethylene (LDPE) into MWCNTs, yielding 0.91 g·g-1-catalyst MWCNTs at 800 °C as compared to 0.42 and 0.14 g·g-1-catalyst using Fe-dmu and Fe-mu, respectively. Fe-dmu favored the growth of MWCNTs with smaller outer diameters. Fe-u demonstrated high efficiency during operation using a continuous flow of pyrolysis gas from a mixture of polyolefins (70 wt% polypropylene, 6 wt% LDPE and 24 wt% high density polyethylene) producing 4.28 g·g-1-catalyst MWCNTs at 3.2% plastic conversion efficiency and a stable H2 flow for 155 min (25-32 vol%). The obtained data demonstrate that the selection of an appropriate precipitating agent for hydrothermal synthesis allows for the production of highly active Fe2O3-Al2O3 catalysts for the upcycling of polyolefin plastic waste into MWCNTs and H2. Economic Development Board (EDB) Nanyang Technological University The authors would like to acknowledge the Nanyang Environment and Water Research Institute, Nanyang Technological University (Singapore) and Economic Development Board (Singapore) for financial support of this research. 2022-09-21T01:53:15Z 2022-09-21T01:53:15Z 2022 Journal Article Veksha, A., Muhammad Zahin Mohamed Amrad, Chen, W. Q., Dara Khairunnisa Mohamed, Tiwari, S. B., Lim, T. & Lisak, G. (2022). Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics. Chemosphere, 297, 134148-. https://dx.doi.org/10.1016/j.chemosphere.2022.134148 0045-6535 https://hdl.handle.net/10356/161823 10.1016/j.chemosphere.2022.134148 35240158 2-s2.0-85125623273 297 134148 en Chemosphere © 2022 Elsevier Ltd. All rights reserved. |
| spellingShingle | Engineering::Environmental engineering Hydrothermal Synthesis Multi-walled Carbon Nanotubes Veksha, Andrei Muhammad Zahin Mohamed Amrad Chen, Wen Qian Dara Khairunnisa Mohamed Tiwari, Satya Brat Lim, Teik-Thye Lisak, Grzegorz Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics |
| title | Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics |
| title_full | Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics |
| title_fullStr | Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics |
| title_full_unstemmed | Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics |
| title_short | Tailoring Fe₂O₃-Al₂2O₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics |
| title_sort | tailoring fe₂o₃ al₂2o₃ catalyst structure and activity via hydrothermal synthesis for carbon nanotubes and hydrogen production from polyolefin plastics |
| topic | Engineering::Environmental engineering Hydrothermal Synthesis Multi-walled Carbon Nanotubes |
| url | https://hdl.handle.net/10356/161823 |
| work_keys_str_mv | AT vekshaandrei tailoringfe2o3al22o3catalyststructureandactivityviahydrothermalsynthesisforcarbonnanotubesandhydrogenproductionfrompolyolefinplastics AT muhammadzahinmohamedamrad tailoringfe2o3al22o3catalyststructureandactivityviahydrothermalsynthesisforcarbonnanotubesandhydrogenproductionfrompolyolefinplastics AT chenwenqian tailoringfe2o3al22o3catalyststructureandactivityviahydrothermalsynthesisforcarbonnanotubesandhydrogenproductionfrompolyolefinplastics AT darakhairunnisamohamed tailoringfe2o3al22o3catalyststructureandactivityviahydrothermalsynthesisforcarbonnanotubesandhydrogenproductionfrompolyolefinplastics AT tiwarisatyabrat tailoringfe2o3al22o3catalyststructureandactivityviahydrothermalsynthesisforcarbonnanotubesandhydrogenproductionfrompolyolefinplastics AT limteikthye tailoringfe2o3al22o3catalyststructureandactivityviahydrothermalsynthesisforcarbonnanotubesandhydrogenproductionfrompolyolefinplastics AT lisakgrzegorz tailoringfe2o3al22o3catalyststructureandactivityviahydrothermalsynthesisforcarbonnanotubesandhydrogenproductionfrompolyolefinplastics |