Eggshells valorization from waste materials into highly efficient hydroxyapatite catalyst for methane dry reforming reaction

In recent years, sustainable and circular approaches to material synthesis and catalysis have gained significant interest. This study introduces an innovative and patented hydroxyapatite (HAP) formulation, synthesized from waste eggshells through a low-temperature route, and used as a catalyst support in dry reforming of methane (DRM). Four formulations were developed by varying theoretical Ca/P ratios (1.47 and 1.67) and synthesis temperatures (40 °C and 60 °C) to evaluate their impact on catalytic performance. All catalysts exhibited high CH 4 conversion (>90%), while CO 2 conversion and syngas selectivity varied depending on synthesis conditions. The Ca/P = 1.67 sample synthesized at 60 °C showed the best performance, combining high CO 2 and CH 4 conversion and stability. This was attributed to favorable surface properties, including an abundance of acid sites for Ni dispersion and basic sites that enhance CO 2 adsorption and carbon removal.