Assessing the effect of acid and alkali treatment on a halloysite-based catalyst for dry reforming of methane
<p dir="ltr">Dry reforming of methane (DRM) has recently received wide attention owing to its outstanding performance in the reduction and conversion of CH<sub>4</sub> and CO<sub>2</sub> to syngas (H<sub>2</sub> and CO). From an industrial perspect...
محفوظ في:
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| مؤلفون آخرون: | , , , , , |
| منشور في: |
2024
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| الملخص: | <p dir="ltr">Dry reforming of methane (DRM) has recently received wide attention owing to its outstanding performance in the reduction and conversion of CH<sub>4</sub> and CO<sub>2</sub> to syngas (H<sub>2</sub> and CO). From an industrial perspective, nickel (Ni)-supported catalysts have been deemed among the most suitable catalysts for DRM owing to their low cost and high activity compared to noble metals. However, a downside of nickel catalysts is their high susceptibility to deactivation due to coke formation and sintering at high temperatures. Using appropriate supports and preparation methods plays a major role in improving the activity and stability of Ni-supported catalysts. Halloysite nanotubes (HNTs) are largely utilized in catalysis as a support for Ni owing to their abundance, low cost, and ease of preparation. The treatment of HNTs (chemical or physical) prior to doping with Ni is considered a suitable method for increasing the overall performance of the catalyst. In this study, the surface of HNTs was activated with acids (HNO<sub>3</sub> and H<sub>2</sub>SO<sub>4</sub>) and alkalis (NaOH and Na<sub>2</sub>CO<sub>3</sub> + NaNO<sub>3</sub>) prior to Ni doping to assess the effects of support treatment on the stability, activity, and longevity of the catalyst. Nickel catalysts on raw HNT, acid-treated HNT, and alkali-treated HNT supports were prepared via wet impregnation. A detailed characterization of the catalysts was conducted using X-ray diffraction (XRD), BET surface area analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), solid-state nuclear magnetic resonance (ssNMR), H<sub>2</sub>-temperature programmed reduction, (H<sub>2</sub>-TPR), CO<sub>2</sub>-temperature programmed desorption (CO<sub>2</sub>-TPD), and Ni-dispersion via H<sub>2</sub>-pulse chemisorption. Our results reveal a clear alteration in the structure of HNTs after treatment, while elemental mapping shows a uniform distribution of Ni throughout all the different supports. Moreover, the supports treated with a molten salt method resulted in the overall highest CO<sub>2</sub> and CH<sub>4</sub> conversion among the studied catalysts and exhibited high stability over 24 hours testing.</p><h2>Other Information</h2><p dir="ltr">Published in: RSC Advances<br>License: <a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">https://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://doi.org/10.1039/D3RA07990B" target="_blank">https://doi.org/10.1039/D3RA07990B</a></p><p dir="ltr">Additional institutions affiliated with: Core Labs - HBKU</p> |
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