In the revised manuscript, it was found that the SWCNT has
unignorable amount of metallic impurity (25%). Additional experiment
using more purified SWCNT (purified by acid treatment etc.) is
strongly required, because such metallic impurities should affect
catalytic performance.
上述是其中一位审稿人提出的问题，这是文章第二次修改，只有这一个问题，另一个审稿人建议接收，我在最短时间内应该怎么回复或修改。（6月毕业所以时间比较紧，恳请各位大佬帮帮忙。）
