Environmental electrochemistry

Geo-electrochemistry in deep-sea hydrothermal vents

Geo-electrochemistry deals with the interaction between electron transfer and chemical reactions in the mineral/fluid interface. In deep-sea hydrothermal vents, water/rock interaction generates reducing species in the hydrothermal fluids, which forms a steep chemical gradient with the seawater. In our paper, we reported a new pathway to reduce nitrate/nitrite to ammonia, which serves as crucial building blocks of amino acids and other N-containing organic molecules. 


Geo-electrochemistry on icy planeteismals

A long-standing question regarding carbonaceous chondrites (CCs) is how the CCs’ organics were sourced and converted before and after the accretion of their parent bodies. Growing evidence shows that amino acid abundances in CCs decrease with an elongated aqueous alteration. However, the underlying chemical processes are unclear. If CCs’ parent bodies were water-rock differentiated, pH and redox gradients can drive electrochemical reactions by using H2 as an electron source. Here, in our recent paper on Nature Communications and Science Advances, we simulate such redox conditions and demonstrate that α-amino acids are electrochemically altered to monoamines and α-hydroxy acids on FeS and NiS catalysts at 25 oC. This conversion is consistent with their enrichment compared to amino acid analogs in heavily altered CCs. Our results thus suggest that H2 can be an important driver for organic evolution in water-rock differentiated CC parent bodies as well as the Solar System icy bodies that might possess similar pH and redox gradients.