[MIS11-P09] Electrical energy generation at hydrothermal environments in the Solar System estimated by fuel cell model experimentations
Keywords:the Solar System, hydrothermal system, fuel cell model, habitability, electrical energy
Although we have not yet had direct evidence for an electrotrophic ecosystem in a natural setting, spontaneous electrical current through conductive minerals and microbial matrixes that could support a life have been observed in sea floor environments on Earth. A promising example for spontaneous electrical energy generation is the marine hydrothermal environments in which conductive mineral deposits chemically separate hydrothermal fluid and sea water. Studies demonstrated that a marine hydrothermal system being functioning as analogous to a fuel cell generating power where sulfide deposit couples electrochemical oxidation of sulfide in the hydrothermal fluid and reduction of dissolved oxygen in the sea water with its electrocatalytic activity and electrical conductance .
As moons in the Solar System such as Enceladus and Europa are suggested to possess oceans with hydrothermal activity, it is hypothesized that those hydrothermal systems also generate electrical energy that provide free energy capable of supporting a biosphere. The present study is to estimate potentials of electrical energy generation at hydrothermal systems in oceans of the Solar System with laboratory electrochemical model experiments reproducing hydrothermal systems. Namely, electrochemical characterizations were conducted by using electrodes covered by sulfide minerals simulating hydrothermal deposits with electrolytes simulating hydrothermal fluids and seawaters. This presentation discusses electrocatalytic properties and potential power production of simulated hydrothermal systems with results of voltammetry tests and fuel cell polarization tests.
References:  Kumar, A. et al., (2017) Nature Reviews Chemistry 1, 0024.  Yamamoto, M. et al., (2018) ChemElectroChem 5. 2162-2166.