Self‐catalyzed Growth of Nonstoichiometric Single‐crystal Mullite Nanocolumns

The nonstoichiometric Al-rich single-crystal mullite nanocolumns were prepared by sol-gel method through the self-catalyzed growth process. The rectangular nanocolumns are straight and uniform with a width of 100–150 nm and length of 3–4 μm. Detailed structural characterizations suggested that the growth of this novel nonstoichiometric structure was induced by the self-catalyzed process thanks to the presence of surface excess Al adlayers on mullite surfaces.