| Abstract | Low-carbon methane (CH₄) obtained from CO₂ hydrogenation is a promising option for reducing greenhouse gases (GHG) emissions from carbon-intensive fossil fuel-based energy production, but catalytic performance, especially in low temperatures, still needs to be improved before large-scale implementation. In this work, it is proposed the use of hydroxyapatite (HAP) as an alternative catalyst support to validate its performance for CO₂ hydrogenation to CH₄. In addition, for the first time in literature, the influence of process conditions (temperature, gas hourly space velocity and Ni metal load) on the performance of HAP-supported catalysts is investigated on semi-pilot scale. CO₂ conversion is favored up to 400 °C, despite the thermodynamic limitations of the hydrogenation reaction. Ni-based catalysts present the best performance for CO₂ hydrogenation with a maximum CO₂ conversion around 88% under optimized conditions (20 wt.% Ni, T = 350 °C, GHSV = 320 h⁻¹) with 100% CH₄ selectivity and no CO production up to 450 °C. Finally, long-term operation of 20Ni/HAP for 50 h on semi-pilot scale shows a robust performance with 83% CO₂ conversion, 100% CH₄ selectivity and no signs of catalyst deactivation. The performance HAP-based catalyst presented here demonstrates the feasibility of HAP as alternative catalyst support for CO₂ hydrogenation and the potential for process upscaling with HAP-supported catalysts. |
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