N-B-OH Site-activated Graphene Quantum Dots for Boosting Electrochemical Hydrogen Peroxide Production.

Carbon materials are considered promising 2/4 e - oxygen reduction reaction (ORR) electrocatalysts for synthesizing H 2 O 2 /H 2 O via regulating heteroatom dopants and functionalization. Here, we designed various doped and functionalized graphene quantum dots (GQDs) to reveal the crucial active sites of carbon materials for ORR to produce H 2 O 2 . Density functional theory (DFT) calculations predict that the edge structure involving edge N, B dopant pairs and further -OH functionalization to the B (N-B-OH) is an active center for ORR via a 2 e - pathway. To verify the above predication, GQDs with an enriched density of N-B-OH (NBO-GQDs) were designed and synthesized by the hydrothermal reaction of -NH 2 edge-functionalized GQDs with H 3 BO 3 forming six-member heterocycle containing the N-B-OH structure. When dispersed on conductive carbon substrates, the NBO-GQDs show H 2 O 2 selectivity of over 90% at 0.7 V-0.8 V versus RHE in the alkaline solution in a rotating ring-disk electrode setup. The selectivity retains 90% of the initial value after a 12 h stability test. In a flow cell setup, the H 2 O 2 production rate is up to 709 mmol g catalyst -1 h -1 , superior to most reported carbon- and metal-based electrocatalysts. This work provides molecular insight into the design and formulation of highly efficient carbon-based catalysts for sustainable H 2 O 2 production. This article is protected by copyright. All rights reserved.