Multimetallic Hierarchical Aerogels: Shape Engineering of the Building Blocks for Efficient Electrocatalysis.

A new class of multimetallic hierarchical aerogels composed entirely of interconnected Ni-Pdx Pty nano-building-blocks with in situ engineered morphologies and compositions is demonstrated. The underlying mechanism of the galvanic shape-engineering is elucidated in terms of nanowelding of intermediate nanoparticles. The hierarchical aerogels integrate two levels of porous structures, leading to improved electrocatalysis performance.