Electrochemical Reduction of Carbon Dioxide on Pyrite as a Pathway for Abiogenic Formation of Organic Molecules

Abstract

A wide spectrum of electrode potentials of minerals that compose sulfide ores enables the latter, when in contact with hydrothermal solutions, to form galvanic pairs with cathode potentials sufficient for electrochemical reduction of CO2. The experiments performed demonstrated the increase of cathode current on the rotating pyrite disc electrode in a range of potentials more negative than -800 mV in presence of CO2. In high-pressure experiments performed in a specially designed electrochemical cell equipped with a pyrite cathode and placed into autoclave, accumulation of formate was demonstrated after 24 hr passing of CO2 (50 atm, room temperature) through electrolyte solution. The formation of this product started on increasing the cathode potential to -800 mV (with respect to saturated silver chloride electrode). The yield grew exponentially upon cathode potential increase up to -1200 mV. The maximum current efficiency (0.12%) was registered at cathode potentials of about -1000 mV. No formate production was registered under normal atmospheric pressure and in the absence of imposed cathode potential. Neither in experiments, nor in control was formaldehyde found. It is proposed that the electrochemical reduction of CO2 takes part in the formation of organic molecules in hydrothermal solutions accompanying sulfide ore deposits and in 'black smokers' on the ocean floor.

Bio-inspired CO2conversion by iron sulfide catalysts under sustainable conditions

“…11 A recent study has highlighted the catalytic nature of greigite, showing that CO 2 could be converted to CH 4 and CO, but no solution-based products were detected in that study -an essential requirement for prebiotic chemistry. 12 In addition, FeS has been shown to catalyze CO 2 reduction 13 and into a range of thiols in the presence of H 2 S. 14 In this study, we show that CO 2 can be reduced to a range of small organic solution-based molecules that are required for the commencement of pre-biotic chemistry. The use of a greigite surface allows such transformations at a low overpotential, atmospheric pressure and room temperature.…”

Abiotic Condensation Synthesis of Glyceride Lipids and Wax Esters Under Simulated Hydrothermal Conditions

“…Abiotic formation and accumulation of organic matter on Earth might occur in hydrothermal systems (Corliss et al, 1981;Holm, 1992a;Shock, 1993;Yanagawa, 1980;Vladimirov et al, 2004). Thus, hydrothermal settings may provide organic compound precursors for the evolution of life on Earth (Amend and Shock, 1998;Baross and Hoffman, 1985;Ferris, 1992;Hennet et al, 1992;Holm, 1992b;Marshall, 1994;Ozawa et al, 2004;Shock, 1990;Simoneit, 1992Simoneit, , 1995.…”

Catalysis in the Primordial World

“…This hypothesis is supported by the finding that iron and copper sulphide minerals (pyrrhotite, pyrite, covellite, bornite, chalcopyrite, tetrahedrite) proved to be efficient catalysts in converting formamide (H 2 NCHO) into purine, adenine, and other heterocyclic bases under simulated prebiotic conditions. 146 It was also shown that pyrite and greigite (Fe 3 S 4 ) catalyse CO 2 reduction, converting it respectively into formate 147 and methanol, formic, acetic and pyruvic acid.…”