The proton-electron transfer (PET) reaction is a fundamental pathway in redox catalysis that drives critical processes from enzymatic reactions to sustainable fuel generation. Yet its efficient implementation in heterogeneous systems often necessitates liquid-phase molecular mediators, which limit sustainability and simplicity. Direct H2O2 synthesis exemplifies this challenge, where high selectivity conventionally requires organic solvents to mediate PET and suppress side reactions. Herein, this limitation is mitigated by employing C60 as a solid-state replacement for molecular mediators; we report a palladium adatom catalyst on C60 that enables direct H2O2 synthesis in pure water, achieving an exceptional rate of 150 mol kgcat-1 h-1 with 90% selectivity and a record product concentration of 0.56 wt %. The benchmark performance stems from a "C60-buffered PET" mechanism, wherein C60 dynamically regulates both electron density and proton/hydrogen species flux, which cooperates with the selective palladium adatom site to inhibit both O-O bond cleavage and overhydrogenation.
Yu et al. (Wed,) studied this question.