Highly catalytic spherical carbon nanocomposites allowing tunable activity via controllable Au-Pd doping

► This work resolves a problem of doping a submicron matrix internally with Pd NPs. ► The NPs locate inside a shell from beneath the CS' surface to about 100 nm below. ► We prepared Au-Pd/CS catalysts with Au:Pd atomic ratios varying from 0.4 to 4.6. ► The growth of Au and its location relative to the pre-existing Pd are discussed. ► The catalytic activity of the Au-Pd/CS is 100 times over that of the Pd/CS.