From Chemical Gardens to Fuel Cells: Generation of Electrical Potential and Current Across Self‐Assembling Iron Mineral Membranes

Abstract

We examine the electrochemical gradients that form across chemical garden membranes and investigate how self‐assembling, out‐of‐equilibrium inorganic precipitates—mimicking in some ways those generated in far‐from‐equilibrium natural systems—can generate electrochemical energy. Measurements of electrical potential and current were made across membranes precipitated both by injection and solution interface methods in iron‐sulfide and iron‐hydroxide reaction systems. The battery‐like nature of chemical gardens was demonstrated by linking multiple experiments in series which produced sufficient electrical energy to light an external light‐emitting diode (LED). This work paves the way for determining relevant properties of geological precipitates that may have played a role in hydrothermal redox chemistry at the origin of life, and materials applications that utilize the electrochemical properties of self‐organizing chemical systems.

Materials Synthesis and Catalysis in Microfluidic Devices: Prebiotic Chemistry in Mineral Membranes

“…[20] Examples include pump-injection experiments forming chemical garden tubes [21] or flat mineral membranes at interfaces between two solutions. [22] For such experiments, the continuous flow of solutions can maintain steep gradients and drive reactions far from the thermodynamic equilibrium, which is key for simulating the conditions at hydrothermal vents. Furthermore, our group demonstrated the formation of pyrophosphate catalyzed by thin mineral membranes in microfluidic devices.…”

Silica Metal Oxide Vesicles Catalyze Comprehensive Prebiotic Chemistry

“…It has been experimentally demonstrated that these alkaline waters induce the growth of self-assembledm ineral structures, [17] including silica/carbonateb iomorphs mimicking the morphologyo f primitive organisms, calcium carbonate mesocrystalss imilar to those formed in biominerals, and silica metal oxy/hydroxide bilayer membranes, also known as silica gardens, with interesting catalytic properties. [18][19][20] We have synthesized these mineral membranes in alkaline silica-rich solutions similart ot hose deriving from serpentinization reactions in the presence of formamide at 80 8C. Rather than pelletsofsalts used in classical silica garden experiments,w eu sed microdropso fs olutions of different soluble metal salts, thus mimickingamore realistic geochemical environment.…”

Electrochemistry at Deep‐Sea Hydrothermal Vents: Utilization of the Thermodynamic Driving Force towards the Autotrophic Origin of Life

“…[5][6][7][8][9][10][11][12][13][14][15] These environments lack sunlight, which constitutes the primary energy source of terrestrial ecosystems. [5][6][7][8][9][10][11][12][13][14][15] These environments lack sunlight, which constitutes the primary energy source of terrestrial ecosystems.…”

“…[5][6][7][8][9][10][11][12][13][14][15] These environments lack sunlight, which constitutes the primary energy source of terrestrial ecosystems. [5,10,12,14,15,17] The 3-dimensional columnar struc-ture of the chimney wall establishes spatial thermodynamic gradients, [5,12] and the catalytic nature of its exterior [10] is thought to allow CO 2 to be reduced electrochemically to CO, HCOOH, and CH 4 . [5,10,12,14,15,17] The 3-dimensional columnar struc-ture of the chimney wall establishes spatial thermodynamic gradients, [5,12] and the catalytic nature of its exterior [10] is thought to allow CO 2 to be reduced electrochemically to CO, HCOOH, and CH 4 .…”