Monomolecule Coupled to Oxygen-Doped Carbon for Efficient Electrocatalytic Hydrogen Peroxide Production.

The electrocatalytic production of hydrogen peroxide (H2O2) is an ideal alternative for the industrial anthraquinone process because of environmental friendliness and energy efficiency, depending on the activity and selectivity of catalysts. Carbon-based materials possess prospects as candidate catalysts for the production of H2O2. Herein, cedar-derived monolithic carbon catalysts modified with coupling oxygen doping and phthalocyanine molecules are synthesized. Cobalt phthalocyanine (CoPc) molecules are introduced onto the carbon surface to construct monomolecular active sites via π-π stacking. The electronic structure of CoPc is modulated by oxygen doping on carbon substrates, mediated by monomolecular π-π stacking. A synergistic effect optimally modulated the interaction between CoPc and key intermediate to H2O2. The energy barrier for oxygen reduction is reduced to optimize the selectivity to H2O2. CoPc@OCW provided up to 99% selectivity to H2O2 at 0.7 V versus RHE. In a three-phase flow cell, CoPc@OCW achieved an H2O2 yield up to 10.4 mol·g-1·h-1 at 0.2 V versus RHE with stable running for 24 h. The advantages of carbon-based catalysts including the adjustable chemical structure depending on π-π stacking and electronic structure of carbon atoms through oxygen doping improved the catalytic performances in the production of H2O2. This proof-to-concept research demonstrates the potential application of carbon-based molecular catalysts for electrochemical synthesis.