Ultrathin two-dimensional metals with fully exposed (111) facets.

Large-size ultrathin two-dimensional (2D) metals with a fully exposed (111) surface have been synthesized by a heat-pressing process. As a result of the compact (111) surface arrangement, an ultrathin Pt 5 nm 2D metal exhibits a superior methanol electro-oxidation performance than an as-sputtered Pt 5 nm thin film (1.8, 2.2 and 5.0 times higher specific activity under different scanning cycles).