HCN-derived polymers are a heterogeneous group of complex substances synthesized from pure HCN; from its salts; from its oligomers, specifically its trimer and tetramer, amino-nalono-nitrile (AMN) and diamino-maleo-nitrile (DAMN), respectively; or from its hydrolysis products, such as formamide, under a wide range of experimental conditions. The characteristics and properties of HCN-derived polymers depend directly on the synthetic conditions used for their production and, by extension, their potential applications. These puzzling systems have been known mainly in the fields of prebiotic chemistry and in studies on the origins of life and astrobiology since the first prebiotic production of adenine by Oró in the early years of the 1960s. However, the first reference regarding their possible role in prebiotic chemistry was mentioned in the 19th century by Pflüger. Currently, HCN-derived polymers are considered keys in the formation of the first and primeval protometabolic and informational systems, and they may be among the most readily formed organic macromolecules in the solar system. In addition, HCN-derived polymers have attracted a growing interest in materials science due to their potential biomedical applications as coatings and adhesives; they have also been proposed as valuable models for multifunctional materials with emergent properties such as semi-conductivity, ferroelectricity, catalysis and photocatalysis, and heterogeneous organo-synthesis. However, the real structures and the formation pathways of these fascinating substances have not yet been fully elucidated; several models based on either computational approaches or spectroscopic and analytical techniques have endeavored to shed light on their complete nature. In this review, a comprehensive perspective of HCN-derived polymers is presented, taking into account all the aspects indicated above.

In this work, we have described the characterization of hybrid silica nanoparticles of 50 nm size, showing outstanding size homogeneity, a large surface area, and remarkable CO₂ sorption/desorption capabilities. A wide battery of techniques was conducted ranging from spectroscopies such as: UV-Vis and IR, to microscopies (SEM, AFM) and CO₂ sorption/desorption isotherms, thus with the purpose of the full characterization of the material. The bare SiO₂ (50 nm) nanoparticles modified with 3-aminopropyl (triethoxysilane), APTES@SiO₂ (50 nm), show a remarkable CO₂ sequestration enhancement compared to the pristine material (0.57 vs. 0.80 mmol/g respectively at 50 °C). Furthermore, when comparing them to their 200 nm size counterparts (SiO₂ (200 nm) and APTES@SiO₂ (200 nm)), there is a marked CO₂ capture increment as a consequence of their significantly larger micropore volume (0.25 cm³/g). Additionally, ideal absorbed solution theory (IAST) was conducted to determine the CO₂/N₂ selectivity at 25 and 50 °C of the four materials of study, which turned out to be >70, being in the range of performance of the most efficient microporous materials reported to date, even surpassing those based on silica.

Space experiments are a technically challenging but a scientifically important part of astrobiology and astrochemistry research. The International Space Station (ISS) is an excellent example of a highly successful and long-lasting research platform for experiments in space, that has provided a wealth of scientific data over the last two decades. However, future space platforms present new opportunities to conduct experiments with the potential to address key topics in astrobiology and astrochemistry. In this perspective, the European Space Agency (ESA) Topical Team Astrobiology and Astrochemistry (with feedback from the wider scientific community) identifies a number of key topics and summarizes the 2021 “ESA SciSpacE Science Community White Paper” for astrobiology and astrochemistry. We highlight recommendations for the development and implementation of future experiments, discuss types of in situ measurements, experimental parameters, exposure scenarios and orbits, and identify knowledge gaps and how to advance scientific utilization of future space-exposure platforms that are either currently under development or in an advanced planning stage. In addition to the ISS, these platforms include CubeSats and SmallSats, as well as larger platforms such as the Lunar Orbital Gateway. We also provide an outlook for in situ experiments on the Moon and Mars, and welcome new possibilities to support the search for exoplanets and potential biosignatures within and beyond our solar system.

We have demonstrated that the annealing process for cleaning pyrite surfaces is a critical parameter in promoting ordering on the surface and driving surface reactivity. Furthermore, we describe a spectroscopic surface characterization of the presence or absence of the surface ordering, as indicated by the Low Energy Electron Diffraction (LEED) pattern, as a function of the surface annealing process. Complementary X-ray photoemission spectroscopy (XPS) results provide evidence that longer annealing processes of over 3 hours repair the sulfur vacancies in the pyrite, making FeS species partially disappear in favor of FeS₂ species. These features play an important role in molecular adsorption. We show that in the case of the cystine amino acid on the (100) pyrite surface, the substrate structure is responsible for the chemical adsorption form. The presence of an ordered structure on the surface, as indicated by the LEED pattern, favors the cystine NH₃ ⁺ chemical form, whereas the absence of the surface ordering promotes cystine NH₂ adsorption due to the sulfur-deficient surface. The cystine molecule could then act by changing its chemical functionalities to compensate for the iron surface coordination. The chemical molecular adsorption form can be selected by the surface annealing conditions, implying that environmental conditions could drive molecular adsorption on mineral surfaces. These findings are relevant in several surface processes, and they could play a possible role in prebiotic chemistry surface reactions and iron–sulfur scenarios.

The presence of non-stoichiometric sites on the pyrite(100) surface makes it a suitable substrate for driving the chemical evolution of the amino acid glycine over time, even under inert conditions.

The molecular form of nitrogen, N₂, is universally available but is biochemically inaccessible for life due to the strength of its triple bond. Prior to the emergence of life, there must have been an abiotic process that could fix nitrogen in a biochemically usable form. The UV photo-catalytic effects of minerals such as pyrite on nitrogen fixation have to date been overlooked. Here we show experimentally, using X-ray photoemission and infrared spectroscopies that, under a standard earth atmosphere containing nitrogen and water vapour at Earth or Martian pressures, nitrogen is fixed to pyrite as ammonium iron sulfate after merely two hours of exposure to 2,3 W/m 2 of ultraviolet irradiance in the 200–400 nm range. Our experiments show that this process exists also in the absence of UV, although about 50 times slower. The experiments also show that carbonates species are fixed on pyrite surface.