Olive stone-derived biochar as a sustainable catalyst support for CO2 methanation

The hydrogenation of carbon dioxide (CO2) into methane presents a promising strategy for CO2 utilization. However, the large-scale implementation of this process remains limited by the lack of cost-effective and sustainable catalytic materials. This study explores the potential of biochar derived fr...

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Main Authors: A. Villardon, A. Alcazar-Ruiz, J. Cencerrero, A. Romero, L. Sanchez- Silva, F. Dorado
Format: Article
Language:English
Published: Elsevier 2025-06-01
Series:Journal of CO2 Utilization
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Online Access:http://www.sciencedirect.com/science/article/pii/S2212982025000861
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Summary:The hydrogenation of carbon dioxide (CO2) into methane presents a promising strategy for CO2 utilization. However, the large-scale implementation of this process remains limited by the lack of cost-effective and sustainable catalytic materials. This study explores the potential of biochar derived from agro-industrial waste, specifically olive stones, as an innovative and eco-friendly support for Ni-based catalysts in CO2 methanation. Three different chemical activation methods (KOH, ZnCl2, and H3PO4) were applied to enhance the textural and structural properties of the biochar, significantly influencing its catalytic performance. Among the tested materials, KOH-activated biochar (10Ni-KOH) exhibited superior Ni dispersion, enhanced surface area, and an increased number of moderately strong basic sites, which are crucial for CO2 activation. This catalyst achieved a CO2 conversion of 72 % and a CH₄ selectivity of 95.5 %, outperforming the other formulations. In contrast, biochar activated with H3PO4 led to the encapsulation of Ni particles within a phosphorus matrix (as demonstrated by TEM images), while ZnCl₂ activation promoted the formation of Ni-Zn alloys (as indicated by XPS and XRD analysis), both of which hindered methanation efficiency. These findings highlight the transformative potential of biochar as a low-cost and sustainable catalyst support, offering a viable alternative to conventional materials for CO2 methanation. By leveraging agricultural residues, this approach not only contributes to circular economy principles but also enhances the economic and environmental feasibility of Power-to-Methane (P2M) technologies.
ISSN:2212-9839