Two-step electrochemical synthesis of “ant-nest” like Co-O, pyrrolic N co-modified graphite felt for high-efficient H2O2 production

Abstract

Heteroatom modified catalyst applying for the two-electron oxygen reduction reaction has the potential application for efficient on-site production of H2O2. At present, state of the art catalyst synthesis is often energy-intensive and tends to destroy the original structure of heteroatoms. Based on the above considerations, Co-O, pyrrolic N structures co-modified graphite felt catalyst (Co-PDA-GF) is successfully synthesized by a simple two-step electrochemical method. Interestingly, the introduction of Co2+ during the dopamine (DA) polymerization process changes the surface morphology of GF from a “thin-film” like to an “ant-nest” like. The cumulative H2O2 concentration achieves 421 mg L−1 in 6 h test time, which is 16 times higher than that of R-GF, and the Methylene blue (MB) in-situ removal rate reaches 97.2% within 3 h. The enhanced H2O2 yield of Co-PDA-GF catalyst is attributed to the increased oxygen-containing functional groups (-COOH, -C-O-C) and defect structures, and most importantly, Co-O and pyrrolic N synergistic modulation effects on local electronic modulation. This work provides new insights on DA polymerization morphology control and designing of high-efficient 2e− ORR catalyst with a low-energy method.