中文摘要：

考察了Ni基催化剂镍颗粒尺度与乙醇蒸汽重整活性、稳定性的构效关系．通过改Stober法制备了镍颗粒尺度可控的Ni@SiO2壳核型催化剂，研究了具有不同镍颗粒尺度的Ni@SiO2壳核型催化剂，发现催化剂乙醇转化频率随着镍颗粒尺度的增加而增加，当镍颗粒尺寸达到30nm以上时，变化不再明显．镍颗粒尺度对催化剂稳定性也有影响．镍颗粒尺度越大，催化剂积碳速率越快，稳定性越差．结果表明，适当的镍颗粒尺度对催化剂活性和稳定性均至关重要．

英文摘要：

This paper describes the structure-function relationship between the particle size and the activity and stability of Ni based steam reforming catalysts. Based on a modified Stt~ber method, the particle size of Ni@SiO2 core-shell catalysts can be finely controlled. By exploring Ni@SiO2 core-shell catalysts with different Ni particle sizes, it is found that the turnover frequency （TOF） of ethanol increase with increasing Ni particle size, reaching a maximum after Ni particles are larger than 30 nm. The particle size of Ni also affects the stability of the catalyst. With larger Ni particle size, a more pronounced coking is observed, jeopardizing the stability of the catalyst. Our study shows that an appropriate Ni particle size is critical to the activity and stability of steam reforming catalysts.