Unbiased solar H2 production with current density up to 23 mA cm-2 by Swiss-cheese black Si coupled with wastewater bioanode

Lu Lu, Waltteri Vakki, Jeffery A. Aguiar, Chuanxiao Xiao, Katherine Hurst, Michael Fairchild, Xi Chen, Fan Yang, Jing Gu, Zhiyong Ren

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Unbiased photoelectrochemical hydrogen production with high efficiency and durability is highly desired for solar energy storage. Here, we report a microbial photoelectrochemical (MPEC) system that demonstrated superior performance when equipped with bioanodes and black silicon photocathode with a unique "Swiss-cheese" interface. The MPEC utilizes the chemical energy embedded in wastewater organics to boost solar H2 production, which overcomes barriers on anode H2O oxidation. Without any bias, the MPEC generates a record photocurrent (up to 23 mA cm-2) and retains prolonged stability for over 90 hours with high Faradaic efficiency (96-99%). The calculated turnover number for MoSx catalyst during a 90 h period is 495471 with an average frequency of 1.53 s-1. The system replaced pure water on the anode with actual wastewater and achieved waste organic removal up to 16 kg COD m-2 photocathode per day. Cost credits from concurrent wastewater treatment and low-cost design make photoelectrochemical H2 production practical for the first time.

Original languageEnglish (US)
Pages (from-to)1088-1099
Number of pages12
JournalEnergy and Environmental Science
Issue number3
StatePublished - Mar 2019

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution


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