还不是长链烃类。说成水变油,那是中文翻译者胡扯。《自然》新闻提到的也是甲烷。
http://www.nature.com/news/2009/090205/full/news.2009.83.html详细的机理不提了。新闻说“The researchers don't yet understand exactly what happens next, but they think that the carbon dioxide also splits to form oxygen and carbon monoxide, which then reacts with gaseous hydrogen to form methane and water”,不大可信。二氧化碳直接离解成一氧化碳和氧,很难。应该是他们的催化剂功能很强,水分解出的氢可以立即进行水煤气反应(由二氧化碳得到一氧化碳)和甲烷化反应(由一氧化碳得到甲烷)。
但是甲烷加长成为“油”是另外一回事。