Advancing Microbial\nElectrochemical H<sub>2</sub>O<sub>2</sub> Synthesis by Tailoring\nthe Surface Chemistry of Stereolithography-Derived\n3D Pyrolytic Carbon Electrodes

Microbial electrosynthesis of H<sub>2</sub>O<sub>2</sub> offers\nan economical and eco-friendly alternative to the costly and environmentally\ndetrimental anthraquinone process. Three-dimensional (3D) electrodes\nfabricated through additive manufacturing demonstrate significant\nadvantages over carbon electrodes with two-dimensional (2D) surfaces\nin microbial electrosynthesis of H<sub>2</sub>O<sub>2</sub>. Nevertheless,\nthe presence of oxygen-containing free acidic groups on the prototype\nelectrode surface imparts hydrophilic properties to the electrode,\nwhich affects the efficiency of the two-electron oxygen reduction\nreaction for H<sub>2</sub>O<sub>2</sub> generation. In this study,\nwe elucidated that the efficiency of microbial H<sub>2</sub>O<sub>2</sub> synthesis is markedly enhanced by utilizing oxygen-free 3D\nelectrodes produced via additive manufacturing techniques followed\nby surface modifications to eradicate oxygen-containing functional\ngroups. These oxygen-free 3D electrodes exhibit superior hydrophobicity\ncompared to traditional carbon electrodes with 2D surfaces and their\n3D printed analogues. The oxygen-free 3D electrode is capable of generating\nup to 130.2 mg L<sup>–1</sup> of H<sub>2</sub>O<sub>2</sub> within a 6-h time frame, which is 2.4 to 13.6 times more effective\nthan conventional electrodes (such as graphite plates) and pristine\n3D printed electrodes. Additionally, the reusability of the oxygen-free\n3D electrode underscores its practical viability for large-scale applications.\nFurthermore, this investigation explored the role of the oxygen-free\n3D electrode in the bioelectro-Fenton process, affirming its efficacy\nas a tertiary treatment technology for the elimination of micropollutants.\nThis dual functionality accentuates the versatility of the oxygen-free\n3D electrode in facilitating both the synthesis of valuable chemicals\nand advancing environmental remediation. This research introduces\nan innovative electrode design that fosters efficient and sustainable\nH<sub>2</sub>O<sub>2</sub> synthesis while concurrently enabling subsequent\nenvironmental restoration.