Effect of Sr Incorporation and Ni Exsolution on Coke Resistance of the Ni/Sr–Al<sub>2</sub>O<sub>3</sub> Catalyst for Dry Reforming of Methane
Jeongmin Kim, Jeong-Cheol Seo, Won-Jun Jang, Kyubock Lee
Abstract
The effects of Sr incorporation over Ni/Al 2 O 3 catalysts were explored for the dry reforming of methane (DRM). Ni-exsolved catalysts (Ni EXS ) and conventional Ni-impregnated catalysts (Ni IMP ) were prepared by using a spray-pyrolysis-assisted evaporation-induced self-assembly (EISA) method to produce a solid solution and mesoporous structures. In the DRM tests, strontium showed crucial effects for improving the resistance of carbon formation and the stability of the catalyst. Particularly, Ni EXS /Sr–Al demonstrated a crystal size growth of 0.8% and a coking rate of 0.012 g c ·g cat –1 ·h –1, which was remarkably lower than those of the other catalysts (Ni IMP /Al, Ni IMP /Sr–Al, and Ni EXS /Al). This study primarily investigated the catalytic properties and strong metal–support interaction, which depended on the preparation procedure, for verifying the origin of the most stable Ni EXS /Sr–Al catalyst. In particular, the roles of promotional Sr in enhancing the CO 2 adsorption/desorption ability of the catalyst at different temperatures as well as the amount of oxygen species were elucidated in detail.