A close encounter with reality on core-shell catalysts for fuel cells: the outstanding significance of the work is (i) suggestion of a computational methodology to design a specific combination of core and shell materials in terms of both the activity and the durability, (ii) development of a novel facile synthesis of core-shell/C electrocatalysts, and (iii) experimental validation of the design and synthesis of the core-shell/C catalysts and their performance as well as long-term stability.