Metallic Honeycomb Catalysts for Methane Steam Reforming: Effect of the Bimetallic Surface Coating on Catalytic Properties

Abstract

Metallic honeycomb catalysts are promising candidates for fuel cell and small-scale onsite hydrogen production applications. In this study, high-cell-density Ni honeycomb catalysts coated with a series of bimetallic surface layers were synthesized. Their catalytic performance for CH4 steam reforming was investigated under a low steam-to-carbon ratio of 1.36 and a gas hourly space velocity of 6400 h-1 in the temperature range of 400–700°C. The catalysts coated with Ni-Mg and Ni-Zr showed excellent catalytic performance, reaching a high CH4 conversion and CO selectivity close to the equilibrium values within the test temperature range. The enhanced catalytic performance of the Ni-Mg and Ni-Zr coatings was attributed to the formation of oxide-supported fine Ni particles. In contrast, the catalysts coated with Ni-Fe and Ni-Sn exhibited an extremely low activity, which was lower than that of the catalyst coated with only Ni. The low activity of the Ni-Fe and Ni-Sn coatings is supposed to be due to the formation of aggregated Ni3Fe, Ni3Sn, and Ni3Sn2 phases.