Dynamic gas‐diffusion electrodes for oxygen electroreduction to hydrogen peroxide

Abstract

AbstractFlow‐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%.