Facile synthesis of hollow hierarchical Ni/γ-Al2O3 nanocomposites for methane dry reforming catalysis

Abstract

Hydrogen reduction of hierarchical spinel intermediates that were synthesized by a facile hydrothermal method results in Ni/γ-Al₂O₃ nanocomposites with Ni nanoparticles (∼5.5 nm) well dispersed and embedded in nanoflakes of the hollow Al₂O₃ microspheres. The good dispersion of small metal nanoparticles and strong metal–support interactions that resulted from decomposition of spinel intermediates during reduction are essential for the efficient and sustainable high temperature dry reforming of methane (DRM) catalysis. The high surface area (170 m² g⁻¹) composite catalysts show coke and sintering resistance in long term DRM catalysis at 750 °C, the highest temperature ever tested for hierarchical nanostructures. Ni loadings and the calcination temperatures of the spinel intermediate are investigated for their effect on the morphology and the catalytic performance of the final catalysts. It is interesting that some initially non-active control catalysts can be activated during long term testing.