Metal nanocrystals with high-index facets (HIFs) have drawn significant attention for their superior catalysis activity compared to that of low-index faces. However, because of the high surface energy of HIFs, it is still challenging to preserve HIFs during the growth of nanocrystals. In this study, highly selective Pt concave nanocubes (CNCs) with high-index {hk0} facets have been successfully prepared in a simple aqueous solution. The vital role of glycine as the surface controller in the formation of CNCs was demonstrated. These Pt CNCs exhibited enhanced specific activities toward the electro-oxidation of methanol and formic acid in comparison to commercial Pt black and Pt/C catalysts.