Ceria supported nickel catalysts for CO removal from H₂-rich gas

Abstract CO in H₂-rich gas must be removed to meet various requirements in industrial applications. Four methods, i.e., the precipitation method using aqueous ammonia, the complexing method using urea, the complexing method using citric acid and the precipitation method using ammonium carbonate, were adopted to prepare samples NiO/CeO₂ as catalyst precursors for removal of CO from H₂-rich gas via selective methanation reaction. The sample NiO/CeO₂ prepared by the precipitation method using aqueous ammonia as precipitant exhibited the highest catalytic activity both for CO methanation and for CO₂ methanation after reduction prior to the catalytic reaction. Chlorine ion was then doped to suppress CO₂ conversion. Effect of chlorine doping was investigated. Over the optimal catalyst 40%Ni(Cl_0.2)/CeO₂, CO in the H₂-rich gas was removed to below 10 ppm with selectivity of 60% or higher at reaction temperatures 230–250 °C in the test period of 75 h.