Morphology effect of nano-hydroxyapatite as support for loading Ni in methane dry reforming

Abstract

In this paper, hydroxyapatite (HAP) with nanorod, nanosheet and nanowire morphologies were synthesized with different surface Ca, O and P distributions. After loading 1.25% of nickel, Ni/HAP-R, Ni/HAP-S and Ni/HAP-W catalysts were obtained and applied for MDR. Among them, the Ni/HAP-R catalyst showed the best performance. The geometric structure, electronic properties and surface basicity of the catalyst were characterized by XRD, N₂ sorption, FT-IR, XPS and CO₂-TPD. It proved that HAP-R possessed the larges surface area, thus beneficial for Ni dispersion to obtain high MDR activity. Meanwhile, it was rich in Ca-O-P which could accelerate the CO₂ activation for coke elimination. TPSR experiments further confirmed that the deep cracking of methane on Ni/HAP-R catalyst was inhibited. However, it could be accelerated in the presence of CO₂ to produce CO and H₂. In this case, Ni/HAP-R catalyst showed excellent anti-coking performance. This study provides inspiration for the design and synthesis of highly stable heterogeneous catalysts.