【摘要】 采用浸渍法制备了Ir/CeO2催化剂,考察了催化剂的CO氧化活性。随着Ir负载量的增加,Ir/CeO2催化剂的CO氧化活性先上升后下降,当Ir的负载量为1%时,催化剂的活性最高。Ir/CeO2催化剂中Ir以IrO2的形式存在,当低负载量(≤1%)时以高分散形式存在;高负载量(>1%)时以晶相IrO2的形式存在。随着Ir负载量增加,Ir粒子逐渐变大,反应比速率和反应转换频率(TOF)逐渐下降,表明小粒子上具有更高的CO反应活性。同时也发现金属态Ir催化剂的CO氧化活性高于氧化态IrOx催化剂。更多还原

【Abstract】 A series of Ir/CeO2 catalysts were prepared by an impregnation method,and were tested for CO oxidation.It was found that the activity of Ir/CeO2 catalysts for CO catalytic oxidation rose first and then declined with Ir loading.The catalysts showed the highest activity when Ir content was 1%.Ir existed in the form of IrO2 in the Ir/CeO2 catalysts.IrO2 was highly dispersed with low Ir loading(≤1%),and existed as crystalline phase with high Ir loading(>1%).Ir particle size increased gradually with Ir loading,but specific rate and turnover frequency(TOF) declined gradually.It indicated that the catalyst with small particle size had a higher CO reactivity.It was also found that for CO oxidation,the activity of Ir catalyst with metal state was higher than that with oxidation state.更多还原