In this paper

Ni/Zr-Yb-O catalysts with different sodium contents are prepared by a co-precipitation method

using aqueous Na

2

CO

3

solution as a precipitant

and the effect of sodium on the catalyst structure and catalytic performance for syngas methanation is extensively investigated using five Ni/Zr-Yb-O catalysts

containing 0

0.5

1.5

4.5 and 13.5 wt% Na

+

those are denoted as Cat-1

Cat-2

Cat-3

Cat-4 and Cat-5 respectively. It is found that the interaction between Ni and support determines the catalytic performance of Ni/Zr-Yb-O and the residual sodium content negatively affects the interaction between Ni and support. Cat-1 exhibits an excellent catalytic performance. During a long run time of 380 h

no deactivation is observed and both CO conversion and CH

4

selectivity maintain a level above 90%. However

Cat-3 and Cat-5 suffer rapid deactivation under the same reaction condition. The characterization results indicate the strong interaction between Ni and support enables Cat-1 to possess well dispersed Ni species

resistance to sintering and carbon deposition and thus the exc

ellent catalytic performance. However

the presence of sodium ions over Ni/Zr-Yb-O degrades the interaction between Ni and support and the catalytic performance

especially for the stability. The relative weak interaction between Ni and support results in severe sintering of both ZrO

2

and Ni under the reaction condition

carbon deposition and the poor catalytic performance.