Chemical Identification of Catalytically Active Sites on Oxygen-doped Carbon Nanosheet to Decipher the High Activity for Electro-synthesis Hydrogen Peroxide.

Abstract

Electrochemical production of hydrogen peroxide through two-electron (2e- ) oxygen reduction reaction (ORR) is an on-site and clean route. Oxygen-doped carbon materials with high ORR activity and H2O2 selectivity have been considered as the promising catalysts, however, there is still a lack of direct experimental evidence to identify true active sites at complex carbon surface. Herein, we proposed a chemical titration strategy to decipher the oxygen-doped carbon nanosheet (OCNS900 ) catalyst for 2e- ORR. The OCNS900 exhibits outstanding 2e- ORR performances with onset potential of 0.825 V (vs. RHE), mass activity of 14.5 A g⁻¹ at 0.75 V (vs. RHE) and H2 O2 production rate of 770 mmol g -1 h -1 in flow cell, surpassing most reported carbon catalysts. Through selective chemical titration of C=O, C-OH, and COOH groups, we found C=O species contributed to the most electrocatalytic activity and were the most active sites for 2e- ORR, which were corroborated by theoretical calculations.

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Identifiers

DOI

10.1002/anie.202104480

Journal

Angewandte Chemie International Edition

Year

2021