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A successful pH control is of critical importance for ensuring efficient H₂ production in two-chamber MECs. In this study, a novel two-chamber MEC is developed with biotic/abiotic hybrid electrodes, which are composed of carbon felt (CF) and stainless steel (SS) mesh. The CF is used for the electrogenic microorganisms attachment catalyzing the oxidation of organic matter (OM); the SS serves as the current collector and the H₂ evolution catalyst. The MEC is operated in the periodic polarity reversal (PPR) mode and two hybrid electrodes work alternately as an anode and a cathode. With the hybrid electrodes and the PPR mode, the pH fluctuation is limited within the range of 6.4–8.6, and the H₂ production is 5.3 times that of control without the PPR mode. The optimal reversal interval is 2 h for maximal H₂ production. The H₂ production increases with the amplitude of the applied voltage (0.7–1.0 V). The using of …