Sunlight offers an inexhaustible and sustainable source of renewable energy to meet our increasing energy demand. However, direct harvesting of solar energy is still challenging due to the variation of natural sunlight and its intermittent nature. To meet the Terawatt Challenge and harness large quantity of energy, current artificial photosynthesis system is showing great promise for its capability of imitating natural photosynthesis. However, the direct water splitting by artificial photosynthesis requires large energy input. Here we demonstrate GaInP₂-TiO₂-MoSx photocathode could couple with microbial electrochemical oxidation process, which used to treat wastewater and recover the chemical energy embedded in organics into electricity, to covert water into hydrogen. The self-sustaining system could generate a current of 0.4 mA/cm² without any external bias and ~10 mA/cm²(with 5 % solar to hydrogen conversion efficiency) at slightly applied bias condition.