Dry reforming of methane over calcium-deficient hydroxyapatite supported cobalt and nickel catalysts

Abstract

Calcium-deficient hydroxyapatite (HAP) non-porous supports were synthesized from Ca(NO3)2 and NH4H2PO4 (conventional synthesis route, HAP_N support) and from CaCO3 and H3PO4 (new synthesis route, HAP_C support) by wet chemical precipitation method. Monometallic and bimetallic supported catalysts were prepared by incipient wetness impregnation using Co(NO3)2 and Ni(NO3)2 salts. The size of Co- and Ni-based particles varied from some nm to dozens nm. Dry reforming of methane (DRM) tests at 700 °C, and 1.6 bar shows that HAP-supported cobalt catalysts were systematically more active than HAP-supported nickel catalysts, which is a new finding in DRM. Increasing the molar ratio of Ca/P from 1.43 (HAP_N) to 1.60 (HAP_C) support led to a slight decrease of the catalytic activity but an improvement of the catalytic stability. Thus, HAP_C support synthesized from CaCO3 and H3PO4 is a good candidate for designing an efficient catalyst for the DRM reaction.