Anti-coking NiCex/HAP catalyst with well-balanced carbon formation and gasification in methane dry reforming

Abstract

Methane dry reforming (MDR) is a promising process to convert two major greenhouse gases into syngas. However, the major drawback of the process is the deactivation of Ni-based catalysts due to carbon deposition and metal sintering. Herein, we prepared hydroxyapatite (HAP) supported Ni catalysts modified by CeO2, which can efficiently promote MDR reaction with the excellent anti-coking property. The strong interaction between Ni and HAP guarantees the stability of highly dispersed Ni particles during the MDR reaction. The neighboring CeO2 over Ni particles could facilitate the mobility of oxygen, which assists the activation of CH4 to CH3O and in some extent hinders the deep cracking of CH4 into deposited carbon. Meanwhile, the kinetic studies indicate that the existence of reactive oxygen species is beneficial for enhancing carbon gasification. Accordingly, the addition of CeO2 balanced the carbon formation and gasification over Ni and therefore efficiently prevented coke accumulation. The exploration of NiCex/HAP catalysts would provide inspiration for future MDR catalyst design.