Electrohydrogenesis or biocatalyzed electrolysis is the name given to a process for generating hydrogen gas from organic matter being decomposed by bacteria.[1] This process uses a modified fuel cell to contain the organic matter and water. A small amount, 0.2–0.8 V[2] of electricity is used, the original article reports an overall energy efficiency of 288% can be achieved (this is computed relative to the amount of electricity used, waste heat lowers the overall efficiency). This work was reported by Cheng and Logan.[3]
↑Shaoan Cheng; Defeng Xing; Douglas F. Call; Bruce E. Logan (March 26, 2009). "Direct Biological Conversion of Electrical Current into Methane by Electromethanogenesis". Environ. Sci. Technol. 43 (10): 3953–8. Bibcode:2009EnST...43.3953C. doi:10.1021/es803531g. PMID19544913.