Dynamic gas‐diffusion electrodes for oxygen electroreduction to hydrogen peroxide

Abstract

Flow‐type electrolytic cell is a viable system for many electrochemical processes, in which gas‐diffusion electrode (GDE) plays a vital role in providing optimal reacting interfaces for improved performances. Different from traditional GDEs with fixed porosity, here we propose a new type of GDE that features flexible diffusion channels. Particularly, the GDE has been assembled by pairing PTFE substrate with Ag‐TCNQ/graphene hydrogels that can be further manipulated through capillary compression. With dynamic adjustment, the average pore size inside GDE ranges from 1750 to 125 nm, and the packing density varies from 56.81 to 446.07 mg cm−3. As a consequence, the as‐assembled flow‐type electrolytic cell can display excellent performances, with a yield rate of 5572 mmol gcat−1 h−1 and Faradic efficiency of 86.4% at 0.267 V (vs. RHE). In addition, a photovoltaic (PV)‐driven flow‐electrolytic system has been assembled that achieves a record solar‐to‐hydrogen peroxide efficiency of 14.8%.

An abnormal size effect enables ampere-level O2electroreduction to hydrogen peroxide in neutral electrolytes

“…Notably, the electrolyte is flowing with the peristaltic pump (8.4 mL min −1 ), which could take away H 2 O 2 intermediately after the ORR, thus facilitating fast reaction kinetics at O 2 /electrolyte/electrode interfaces. The as-generated H 2 O 2 has been determined by titration of titanium sulfate solutions, 26,27 and the corresponding activities and faradaic efficiencies have been calculated on the basis of H 2 O 2 concentration and the applied current.…”

Carbon and Oxygen-Doped Phosphorus Nitride (COPN) for Continuous Selective and Stable H2O2 Production

“…The inset: H 2 O 2 concentration within 70 h of electrolysis (10 h each cycle). (h) Comparative analysis of some of the reported state-of-the-art electrocatalysis for H 2 O 2 production (star shape: neutral electrolyte, triangle shape: basic electrolyte). ,,,− …”

Tandem-Parallel Electrochemical Cells to Produce Hydrogen Peroxide at Reduced Energy Consumption

“…Here, the synergistic effect of a ZnO/rGO nanocomposite can improve the electrocatalytic activities . Specifically, reduced graphene oxide (rGO) has the advantage of high surface area and electrical conductivity. , Thus, the assembly of ZnO on graphene sheets can improve the overall conductivity to facilitate ORR kinetics. On the other hand, ZnO acts as a spacer to effectively separate the graphene sheets and provide large surface areas for electrolyte infiltration.…”