High-efficiency electrogeneration of hydrogen peroxide from oxygen reduction by carbon xerogels derived from glucose

Abstract

Developing highly active and selective, and low cost electrocatalysts for the 2e− oxygen reduction from environmentally friendly precursors is attractive to industrial production and environmental remediation. In this study, carbon xerogels (CXs) were synthesized by the hydrothermal carbonization of glucose and polyaniline (PANI) and then used as catalysts for electrochemical generation of H2O2 from O2. It was found that the H2O2 production performance could be easily tunable by polymerization temperature of PANI (0–80 °C), in which onset potential (−0.45 V to −0.29 V) decreased while the catalytic activity and H2O2 selectivity (47%–94%) increased with the polymerization temperature. CX-80 (prepared at 80 °C) exhibited the best catalytic activity with excellent H2O2 selectivity of 94% in neutral condition, better than most reported electrocatalysts. The H2O2 production was also tested using gas diffusion electrodes modified by CXs, showing a high H2O2 yield (5.1 mg h−1 cm−2) and stability with low energy consumption (7.2 kWh kg−1) at cathode potential of −1.0 V and pH 7. The excellent performance of CX-80 was attributed to large volume of meso-/macropores and high content of C=O. We believed that CX-80 would be a promising metal-free electrocatalyst for sustainable and in-situ H2O2 generation from O2 in energy and environmental fields.