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Abstract

Abiotic synthesis of formate and short hydrocarbons takes place in serpentinizing vents where some members of vent microbial communities live on abiotic formate as their main carbon source. To better understand the catalytic properties of Ni-Fe minerals that naturally exist in hydrothermal vents, we have investigated the ability of synthetic Ni-Fe based nanoparticular solids to catalyze the H₂-dependent reduction of CO₂, the first step required for the beginning of pre-biotic chemistry. Mono and bimetallic Ni-Fe nanoparticles with varied Ni-to-Fe ratios transform CO₂ and H₂ into intermediates and products of the acetyl-coenzyme A pathway — formate, acetate, and pyruvate — in mM range under mild hydrothermal conditions. Furthermore, Ni-Fe catalysts converted CO₂ to similar products without molecular H₂ by using water as a hydrogen source. Both CO₂ chemisorption analysis and post-reaction characterization of materials indicate that Ni and Fe metals play complementary roles for CO₂ fixation.