A Homogeneously Catalyzed Paired Electrolytic Cell for Hydrogen Peroxide Production

Abstract

ABSTRACT The two‐electron water oxidation reaction (2e − ‐WOR) and oxygen reduction reaction (2e − ‐ORR) represent sustainable and promising processes for the electrochemical synthesis of hydrogen peroxide (H 2 O 2 ). The main factor hampering the realization of a paired electrochemical cell for H 2 O 2 production is finding appropriate catalysts for both 2e − ‐ORR and 2e − ‐WOR, able to work under the same experimental conditions. Herein we show that Cu(tmpa)) and Sn‐TMPyP are compatible and efficient catalysts for 2e − ‐ORR and 2e − ‐WOR, respectively. They have been used to assemble a paired electrochemical cell for H 2 O 2 production. The latter exhibits a total overpotential of 570 mV, distributed between the two electrodes. During a 3 h bulk electrolysis experiment, the cathodic Faradaic efficiency ranged from 15% to 19% with a H 2 O 2 production rate of 1.6 µmol h − 1 cm − 2 . Meanwhile, at the anode, the Faradaic efficiency stabilized between 40% and 50%, yielding a H 2 O 2 production rate of 3.5 µmol h − 1 cm − 2 . The remarkable activity of Sn‐TMPyP as a catalyst for the 2e − ‐WOR, ranking among the highest reported for molecular catalysts, is ascribed to the selection of a carbonate buffer as the electrolyte, which enhanced catalytic performance by facilitating dissociation of H 2 O 2 from the Sn catalyst. This work establishes a new benchmark for homogeneous dual‐electrode H 2 O 2 electrosynthesis.