A prevailing scenario of the origin of life postulates thioesters as key intermediates in protometabolism, but there is no experimental support for the prebiotic CO₂ fixation routes to thioesters. Here we demonstrate that, under a simulated geoelectrochemical condition in primordial ocean hydrothermal systems (–0.6 to –1.0 V versus the standard hydrogen electrode), nickel sulfide (NiS) gradually reduces to Ni⁰, while accumulating surface-bound carbon monoxide (CO) due to CO₂ electroreduction. The resultant partially reduced NiS realizes thioester (S-methyl thioacetate) formation from CO and methanethiol even at room temperature and neutral pH with the yield up to 35% based on CO. This thioester formation is not inhibited, or even improved, by 50:50 coprecipitation of NiS with FeS or CoS (the maximum yields; 27 or 56%, respectively). Such a simple thioester synthesis likely occurred in Hadean deep-sea vent environments, setting a stage for the autotrophic origin of life.

An increasing amount of evidence suggests that early ocean hydrothermal systems were sustained sources of ammonia, an essential nitrogen species for prebiotic synthesis of life’s building blocks. However, it remains a riddle how the abiotically generated ammonia was retained at the vent–ocean interface for the subsequent chemical evolution. Here, we demonstrate that, under simulated geoelectrochemical conditions in early ocean hydrothermal systems ( ≤ − 0.6 V versus the standard hydrogen electrode), mackinawite gradually reduces to zero-valent iron ( Fe 0 ), generating interlayer Fe 0 sites. This reductive conversion leads to an up to 55-fold increase in the solid/liquid partition coefficient for ammonia, enabling over 90% adsorption of 1 mM ammonia in 1 M NaCl at neutral pH. A coordinative binding of ammonia on the interlayer Fe 0 sites was computed to be the major mechanism of selective ammonia adsorption. Mackinawite is a ubiquitous sulfide precipitate in submarine hydrothermal systems. Given its reported catalytic function in amination, the extreme accumulation of ammonia on electroreduced mackinawite should have been a crucial initial step for prebiotic nitrogen assimilation, paving the way to the origin of life.

The presence of amino acids in diverse extraterrestrial materials has suggested that amino acids are widespread in our solar system, serving as a common class of components for the chemical evolution of life. However, there are a limited number of parameters available for modeling amino acid polymerization at mineral–water interfaces, although the interfacial conditions inevitably exist on astronomical bodies with surface liquid water. Here, we present a set of extended triple-layer model parameters for aspartate (Asp) and aspartyl-aspartate (AspAsp) adsorptions on two-line ferrihydrite, anatase, and γ-alumina determined based on the experimental adsorption data. By combining the parameters with the reported thermodynamic constants for amino acid polymerization in water, we computationally demonstrate how these minerals impact the AspAsp/Asp equilibrium over a wide range of environmental conditions. It was predicted, for example, that two-line ferrihydrite strongly promotes Asp dimerization, leading to the AspAsp/Asp ratio in the adsorbed state up to 41% even from a low Asp concentration (0.1 mM) at pH 4, which is approximately 5 × 10⁷ times higher than that attainable without mineral (8.5 × 10⁻⁶%). Our exemplified approach enables us to screen wide environmental settings for abiotic peptide synthesis from a thermodynamic perspective, thereby narrowing down the geochemical situations to be explored for life’s origin on Earth and Earth-like habitable bodies.