The effect of adsorbed oxygen species on carbon-resistance of Ni-Zr catalyst modified by Al and Mn for dry reforming of methane

Abstract

Dry reforming of methane was investigated over Ni-Zr catalysts modified by Aluminum and Manganese. The catalysts were characterized by XRD, CO2-TPD, XPS, TGA, and Raman. Among all prepared catalysts, the 5Al-5 Mn (5 wt% Al and 5 wt% Mn) catalyst showed the highest CH4 and CO2 conversion at 700 °C DRM with low carbon deposition. The CO2-TPD results exhibited that the 5Al-5 Mn catalyst had the highest amounts of both total basic sites and medium-strength basic sites, which could promote the adsorption and activation of CO2 molecule during the DRM reaction, and further reduce the carbon deposition. The XRD results suggested that the addition of both Al and Mn led to smaller nickel particle size. Besides, the lower carbon deposition on 5Al-5Mn and 2.5Al-7.5Mn catalyst was derived from a higher content of surface adsorption oxygen species, which was verified by the O 1s results. While the lower number of basic sites, more strong basic sites and larger particle size on 5Mn and 5Al catalysts result in a higher amount of carbon deposition.