Energy and Environmental Engineering

Artificial photosynthesis converts CO₂ to organic substances using only H₂O and sunlight, and hence enables the recycle of emitted CO₂. We have established an artificial photosynthesis technology that continuously produces formic acid –an organic substance– from CO₂ dissolved in an electrolyte at normal temperature and pressure. We constructed a 1 m2-sized artificial photosynthetic cell, and demonstrated a solarto- chemical conversion efficiency of 10.5% that is the world record for large sized cells. We employed the combination of crystalline silicon solar cells and an electrochemical reactor loading original catalyst, and then optimized the electron transport and electrolyte flow to achieve both a practically large size and a high efficiency.

Ammonia can be synthesized from hydrogen by using renewable energy. While it has the advantages of easy liquefaction and higher energy density compared to hydrogen, it is difficult to burn. Our work enables to start the gas turbine with the single ammonia fuel by using a reformer. In addition, we constructed a CO₂-free gas turbine combustion technology that enables the stable combustion even when liquid ammonia is directly supplied during the power generation operation^*.
*Jointly developed with Toyota Motor Corporation and the National Institute of Advanced Industrial Science and Technology (AIST)