Microbial fuel cells (MFCs) are sensitive to acidity variations in both bioelectricity generation and biochemical digestion aspects, therefore online pH monitoring is of necessity to guarantee optimal function of MFCs. Present pH meters hardly fulfill this special need. In this work, we designed a novel voltammetric pH sensor based on electrochemically reduced graphene oxide (rGO) modified screen printed electrode. By surface doping of alizarin, good linearity of pH sensing over the range of 4.0–9.0 can be realized. Fast readout can be acquired within 15 s for each test. pH monitoring for artificial wastewater with inoculum of granular activated sludge in a MFC was successfully illustrated. Specially, it was verified that the performance was improved with alizarin doping due to the enhanced rGO surface proton diffusion. This approach provides an online, calibration-free and long stable pH monitoring method for the future MFC development.

微生物燃料电池 (MFCs) 在生物发电和生化消化方面对酸度变化都很敏感，因此在线 pH 监测对于保证 MFCs 的最佳功能是必要的。目前的 pH 计很难满足这种特殊需要。在这项工作中，我们设计了一种基于电化学还原氧化石墨烯 (rGO) 修饰的丝网印刷电极的新型伏安 pH 传感器。通过表面掺杂茜素，可以在 4.0-9.0 范围内实现良好的 pH 传感线性。每次测试可在 15 秒内获得快速读数。成功地说明了在 MFC 中接种颗粒活性污泥的人工废水的 pH 值监测。特别地，证实了由于增强的 rGO 表面质子扩散，茜素掺杂提高了性能。