Multiple active cobalt species embedded in microporous nitrogen-doped carbon network for the selective production of hydrogen peroxide

To obtain excellent electrocatalysts for improving H 2 O 2 yield and selectivity , we formulated a novel method for embedding cobalt catalytic active sites in porous two-dimensional nitrogen-doped carbon network (CN y ) network and employed them as excellent two-electron oxygen reduction reaction (2e − -ORR) electrocatalysts. The polymeric cobalt-based metal–organic framework (polyCo-MOF) and melamine–cyanuric acid–complex (MCA) hybrid (denoted as polyCo-MOF@MCA) was used as a precursor for preparing a series of electrocatalysts comprising multiple active sites such as metallic Co, CoO x , or Co-N, which are homogeneously embedded in the porous two-dimensional CN y network through pyrolysis at high temperatures (600 °C, 700 °C, and 800 °C) under N 2 atmosphere. The obtained CoO x /Co@CN y,700 hybrid by pyrolyzing polyCo-MOF@MCA at 700 °C displayed remarkably high H 2 O 2 production and large selectivity in an alkaline solution. The possible catalytic mechanism of CoO x /Co@CN y,700 toward 2e − -ORR was identified by determining the catalytic kinetics and control experiments. The cathode assembled with the CoO x /Co@CN y,700 hybrid showed the maximum H 2 O 2 production of 405 mmol L −1 g cat. −1 h −1 with a high Faradaic efficiency of 88.9 % at 0.65 V. The present work demonstrated a novel strategy for identifying excellent electrocatalysts with homogeneously dispersed multiple active sites and high production and selectivity for H 2 O 2 synthesis, extending the applications of porous organic frameworks to the field of clean energy.