Metallic molybdenum sulfide catalyses protometabolic carbon dioxide reaction networks under extreme conditions

The nonenzymatic synthesis of organics from H2–CO2 redox couple forms the foundational basis for prebiotic carbon metabolism. However, constructing comprehensive carbon cycling reaction networks with multiple interlinked subsystems preceding enzymatic catalysis remains challenging. Here, we demonstrate that metallic molybdenum sulfide mimicking Mo-S2-pterin enzyme drives the construction of hydrothermal CO2 reaction networks across five carbon sequestration pathways including acetyl-CoA, reductive tricarboxylic acid, 3-hydroxypropionate-4-hydroxybutyrate, dicarboxylate-4-hydroxybutyrate, and ethylmalonyl-CoA pathways. A total of 32 intermediates and end-products are synthesized from CO2, encompassing five universal metabolic precursors. Spectroscopic and computational studies reveal that molybdenum sulfide containing Mo3+ with vacancy-induced distorted octahedral structure promotes the formation of radicals and enhances their adsorption and coupling in aqueous solutions, leading to CO2 conversion rate of 68.6% and selectivity of up to 70% for C2+ carboxylates. The metal sulfide-catalyzed multiple CO2 reaction networks under extreme conditions could function as a prebiotic precursor to ancient and core metabolic pathways. While nonenzymatic organic synthesis from the H₂–CO₂ redox couple underpins prebiotic carbon metabolism, building integrated, multi-pathway carbon reaction networks prior to enzymatic catalysis remains challenging. Here, the authors show that metallic molybdenum sulfide, mimicking Mo–S₂–pterin enzymes, enables hydrothermal CO₂ reaction networks spanning five carbon sequestration pathways.