“…Besides the durability issues, the catalytic activity needs to be greatly enhanced since the use of expensive Pt needs to be reduced. Therefore, various approaches have been extensively developed, which include alloying Pt with 3 d transition metals (M = Fe, Co, and Ni) [7,8,9,10,11,12,13,14,15], core-shell nanostructures [16], and modification of support materials [17,18].…”