Self-assembled membranes modulate the active site of carbon fiber paper to boost the two-electron water oxidation reaction

Abstract

Two-electron water oxidation (2e-WOR) is an attractive method for the electrosynthesis of hydrogen peroxide (H2O2). However, its practical application is limited by the viable 2e-WOR catalysts that can ensure high selectivity and high H2O2 yield. In this paper, a highly active 2e-WOR electrocatalyst was prepared by modifying carbon fiber paper (CFP) with a self-assembled membrane (SAMs). The SAMs modified CFP can achieve an H2O2 yield of 79.8 μmol min−1 cm−2 and an H2O2 selectivity of 82.5% at a low potential (2.1 V vs. RHE). The DFT calculation reveals that SAMs modification can modulate the *OH binding energy of the active site on CFP, thus leading to a significantly improved selectivity and production rate of H2O2. Moreover, the 2e-WOR performance is found to be independent of the functional tail groups of SAMs because the electron transfer during the 2e-WOR occurs through direct electron transfer via the carbon atoms adjacent to the O=C-M on carbon fiber rather than the well-known electron tunneling through SAMs. This study provides a new strategy for surface modification of 2e-WOR carbon-based catalysts and opens a new way for efficient electrosynthesis of H2O2.