The preparation of high-value fuels and chemicals through the electrochemical carbon dioxide reduction reaction (CDRR) is of great significance to the virtuous cycle of carbon dioxide. However, due to the high overpotential involved in this reaction, high power consumption and high-cost noble-metal-based catalysts are required for driving this process. Herein, the electrochemical CDRR was achieved on biocompatible metal-free nitrogen, phosphorus co-doped carbon-based materials (NP-C) in the microbial fuel cell-microbial electrolysis cell (MFC-MEC) coupling system. As the bioelectrochemistry in MFC supplied power to drive the electrocatalysis in MEC, syngas was spontaneously produced from this coupling system without external energy input. With the NP-C materials as the excellent bifunctional electrocatalyst for the CDRR and oxygen reduction reaction (ORR), the current density of the MEC reached −0.52 mA cm⁻², and the Faradaic efficiencies (FEs) of CO and H₂ were 60% and 40%, respectively, at a load resistance of 10 Ω. Moreover, the CO/H₂ product ratio can be changed by adjusting the load resistance, which will widely meet various demand of syngas usage in further reactions. This study provides a spontaneous and tunable production of syngas in biogas digesters via a electrochemical strategy.

通过电化学二氧化碳还原反应（CDRR）制备高价值燃料和化学物质对二氧化碳的良性循环具有重要意义。然而，由于该反应涉及高电势，因此驱动该过程需要高功耗和高成本的贵金属基催化剂。在本文中，电化学CDRR是在微生物燃料电池-微生物电解池（MFC-MEC）偶联系统中的生物相容性无金属氮，磷共掺杂碳基材料（NP-C）上实现的。由于MFC中的生物电化学提供了动力来驱动MEC中的电催化作用，因此从该耦合系统中自发产生了合成气，而无需外部能量输入。^-2，以及CO和H的法拉第效率（FES）₂分别为60％和40％，在10Ω的负载电阻。而且，可以通过调节负载阻力来改变CO / H ₂产物比率，这将广泛满足进一步反应中使用合成气的各种需求。这项研究通过电化学策略提供了沼气池中自发且可调谐的合成气生产方法。