Cobalt single atom catalysts for the efficient electrosynthesis of hydrogen peroxide

We report the synthesis of cobalt (Co) single atoms (SAs) anchored on N-doped graphitic carbon (Co-SAs/NC) by the pyrolysis of a mixture of cobalt chloride hexahydrate, ethylene diamine tetraacetic acid (EDTA) and polyvinylpyrrolidone (PVP). As an electrocatalyst, the Co-SAs/NC with a surface area of 165.6 m(2) g(-1) and a dominant mesoporous structure exhibited superior two-electron oxygen reduction reaction (2e(-) ORR) activity in 0.1 M KOH electrolyte, affording a very positive onset potential of 0.84 V (vs. RHE) and a H2O2 selectivity of similar to 76.0% at 0.5 V (vs. RHE). The long-term durability tests indicated that the Co-SAs/NC can generate 380.9 +/- 14.85 mu mol H2O2 stably after 10 h of reaction at 0.5 V (vs. RHE) in 0.1 M KOH, showing only similar to 10% decay of the current and the corresponding faradaic efficiency (FE) of similar to 72.1 +/- 4.2%. The superior 2e(-) ORR performance of Co-SAs/NC is ascribed to the synergetic effect of the Co-N-x active sites and nearby oxygen functional groups.