CO Selective Methanation Performance Of Nickel-based Catalysts Over Zirconium-doped SBA Mulechuar Sieve

Proton membrane fuel cell?PEMFC?,an environment-friendly energy source with high energy efficiency and simple structure,is one of the ideal power sources to replace the traditional automobile power system.The deep purification of hydrogen-rich gas is one of the bottlenecks that limit the application of PEMFC.Selective methanation of CO is one of the effective methods to remove a small amount of CO in hydrogen-rich gas.The key lies in the development of the CO selective methanation catalyst with high activity at low temperature,high selectivity and stability.The Ni-based methanation catalyst has good activity and selectivity,and low price which is widely used and studied at present.In this work,a series of Ni-based Zr-doped SBA molecular sieve catalysts were prepared and the CO selective methanation catalytic performance was investigated.The catalysts were characterized by XRD,N₂ adsorption-desorption,H₂-TPR,CO/CO₂-TPD,FTIR,XPS,SEM,TEM,ICP-OES techniques.The relationship between the nature of the catalyst and its catalytic properties was elaborated comprehensively.The main content of the work was shown as follows:?1?The Zr-doped SBA-15 molecular sieve ZrSBA-15 was synthesized by direct hydrothermal method.The effect of the reduction temperature,Zr doping amount and Ni loading on the catalytic performance of Ni-based methanation catalyst supported on ZrSBA-15was investigated.The results showed that proper amount of Zr doping can increase the specific surface area of Ni-based catalyst,enhance the interaction between metal and support,effectively inhibit the agglomeration and sintering of metallic Ni,enhance the adsorption of CO on the catalyst and inhibit the adsorption of CO₂.The activity test displayed that the25Ni/0.05ZrSBA-15 catalyst reduced at 350°C exhibits excellent catalytic performance at low temperature?170-220°C?,which can remove the CO outlet concentration to below 10 ppm with a selectivity greater than 50%.Furthermore,this catalyst had good stability during a long-term stability test?120 h?.?2?The Zr-doped SBA-16 molecular sieve ZrSBA-16 was successfully synthesized by direct hydrothermal method.The Ni-based catalysts were fabricated by impregnation method.The influence of the reduction temperature,Zr doping amount and Ni loading on the catalytic performance of Ni/ZrSBA-16 catalysts was studied systematically.The results show that the Ni-based zirconium-doped SBA-16 zeolite reduced at 450°C with the Zr/Si molar ratio 0.05and the Ni loading 15wt%gave the better catalytic performance of CO selective methanation?i.e.,CO outlet concentration less than 10 ppm and CO-SMET selectivity greater than 50%?over a wide reaction temperature window of 180-230°C.Furthermore,the catalyst also showed high stability with no deactivation during a long-term durability test?120 h?.