Influence of Composition of Nickel-Iron Nanoparticles for Abiotic CO2 Conversion to Early Prebiotic Organics

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 H-2-dependent reduction of CO2, the first step required for the beginning of prebiotic chemistry. Mono and bimetallic Ni Fe nanoparticles with varied Ni-to-Fe ratios transform CO2 and H-2 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 H-2 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.