Enhanced low-temperature activity for CO_2 methanation over Ru doped the Ni/CexZr_((1-x))O_2 catalysts prepared by one-pot hydrolysis method

摘要

A series of 30 wt%Ni/CexZr1-xO2 catalysts doped with Ru ranging from 0 to 5 wt% were prepared by one-pot hydrolysis of metal nitrates with ammonium carbonate for carbon dioxide methanation at low temperature range of 150-310 degrees C. The influences of Ce/Zr molar ratios and Ru contents on the physicochemical properties and catalytic activities of prepared catalysts were systematically investigated. The addition Ru can improve the Ni dispersion and the basicity of the yRu-30Ni/Ce0.9Zr0.1O2 catalysts surface. As a result, their low-temperature catalytic activity had been enhanced over these doped Ru promoted catalysts. The optimal catalyst was 3Ru-30Ni/Ce0.9Zr0.1O2 on which the CO2 conversion reached theoretical equilibrium value as high as 98.2% with the methane selectivity of 100% at a reaction temperature as low as 230 degrees C. Moreover, there was almost no deactivation for the 3Ru-30Ni/Ce0.9Zr0.1O2 catalyst during 300 h at 230 degrees C indicating excellent catalytic stability and coke resistence ability. It was also found that the low-temperature activity of 3Ru-30Ni/Ce0.9Zr0.1O2 catalyst prepared by one-pot hydrolysis method was much higher than the one prepared by impregnation method. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.