Abstract
In this work, the ferrous (Fe(2+)) and graphitic N modified graphene-based composite cathode materials (N-rGO/Fe(3)O(4)) were developed through an in-situ reduction method, aiming to facilitate the two-electron pathway in the oxidation-reduction process. This approach generated a specific concentration of H(2)O(2), enabling the construction of a sediment bio-electro-Fenton system using Fe(2+) released from the cathode materials. Notably, this system operates without the need for proton exchange membranes. During the cathode material preparation, the utilization of Fe(2+) as a reduction agent for graphene oxide (GO), triggered ammonia water to form graphitic N in graphene sheets. This addition enhanced the two-electron pathway, resulting in increased H(2)O(2) production. Specifically, when the Fe(2+) concentration was maintained at 0.1 mol/L, precise preparation of N-rGO/Fe(3)O(4) occurred, leading to a maximum output voltage of 0.528 V and a maximum power density of 178.17 mW/m(2). The degradation of methyl orange (MO) reached 68.91% within a 25-h period, a phenomenon contributed to the presence of graphitic N in the graphene sheets. H(2)O(2), a byproduct of the two-electron pathway in cathode oxidation reduction reaction, played a crucial role in constructing the bio-electro-Fenton system. This system, in conjunction with Fe(2+) released from N-rGO/Fe(3)O(4), facilitated the complete degradation process of MO.