Abstract
Driven by anthropogenic climate change, innovative approaches to defossilize the chemical industry are required. Herein, the first all-electrochemical feasibility study for the complete electrosynthesis of the strong oxidizer and effective disinfectant performic acid is presented. Its synthesis is achieved solely from CO(2), O(2), and H(2)O in a two-step process. Initially, CO(2) is electrochemically reduced to formate employing Bi(2)O(3)-based gas diffusion electrodes in a phosphate-buffered electrolyte. Thereby, high formate concentration (500.7 ± 0.6 mmol L(-1)) and high Faradaic efficiency (86.3 ± 0.3%) are achieved at technically relevant current density (150 mA cm(-2)). Subsequently, the formate acts as (storable) feed electrolyte for the second electrolysis step. Employing carbon-based gas diffusion electrodes, O(2) is reduced to H(2)O(2) and performic acid is directly formed in situ. As before, high H(2)O(2) concentration (1.27 ± 0.06 mol L(-1)) and high Faradaic efficiency (85.3 ± 5.4%) are achieved. Furthermore, performic acid concentration suitable for disinfection is obtained (82 ± 11 mmol L(-1)). In summary, this innovative feasibility study highlights the potential of combining electrochemical CO(2) reduction with H(2)O(2) electrosynthesis, which could provide sustainable access to performic acid in the future.