CeO_2和Pd在Ni/γ-Al_2O_3催化剂中的助剂作用

Promotion Effects of CeO_2 and Pd on Ni/γ-Al_2O_3 Catalyst

采用脉冲微反技术研究了添加n型半导体氧化物CeO2及贵金属Pd对Ni/γ-Al2O3催化剂上CH4积炭/CO2消炭反应性能的影响,并运用BET、TPR、CO2-TPSR及氢吸附等技术对催化剂进行了表征.结果表明,n型半导体氧化物CeO2的添加可以降低Ni/γ-Al2O3催化剂上CH4裂解积炭活性,提高CO2消炭活性,添加少量贵金属Pd可以进一步改变载体Al2O3、助剂CeO2和活性组分Ni之间的相互作用,从而改善Ni/γ-Al2O3催化剂的抗积炭性能.通过Ni-Ce-Pd/γ-Al2O3催化剂上CH4积炭/CO2消炭模型对上述作用机制作出了新的解释.

The influence of the addition of n-type semiconductor oxide CeO2and noble metal Pd to Ni /γ-Al 2O3catalyst on carbon deposition by CH4and carbon elimination by CO2was studied by using a pulse microreac-tion as well as BET?TPR?CO2-TPSRand hydrogen chemisorpton techniques.It was found that,the addit ion of n-type semiconductor CeO2to Ni /γ-Al 2O3catalyst could decrease carbon depo sition activity of CH4and in-crease carbon elimination ability o f CO2;the addition of noble metal Pd could further alter the interaction between support Al 2O3,promoterCeO2and active phase Ni,as a result,the performance of resistance to carbon deposition of Ni /γ-Al 2O3 catalyst was improved.At the same ti me,a new explanaton for the above pro moting effect was put forward by the models of carbon deposition by CH4 and carbon elimination by CO2on the Ni -Ce -Pd /γ-Al 2O3catalyst.