As
a green oxidant, H2O2 can be produced
via the electrochemical reduction of oxygen. However, current techniques
usually require high-pressure air or oxygen gas to accelerate the
oxygen diffusion via bubbling in the electrolyte. Here, we design
a multifunctional gas capture catalyst (GCC) of hierarchical N-doped
Co/carbon heterostructures with a Schottky contact at the interface
for the highly efficient capture and selective transformation of oxygen
from air to H2O2. Tuning the Schottky contact
at the Co/NxC interface boosts H2O2 production in acid media. Remarkably, as the catalyst
in the H-cell without an ion-exchange membrane and a polytetrafluoroethylene
(PTFE) assistant, the Co/N2.1C GCC could provide an accumulated
H2O2 yield of 2413 mg L–1 h–1 (730 mmol g–1 h–1) at 20 mA cm–2 in 0.1 M HClO4 solution
under natural air diffusion. More importantly, consistent Faradaic
efficiencies (75%) at a wide scope of working potentials ranging from
−0.54 to 0.46 V vs RHE were attained. The connected hierarchical
structure of Co/N2.1C GCC remains stable without an obvious
flooding effect confronted by conventional gas flow electrodes. This
work affords valuable information for fabricating highly efficient
2e– ORR catalysts and expands heterojunction catalysts
for H2O2 production.