eprintid: 10084147
rev_number: 18
eprint_status: archive
userid: 608
dir: disk0/10/08/41/47
datestamp: 2019-10-24 11:07:53
lastmod: 2021-09-19 23:52:16
status_changed: 2019-10-24 11:07:53
type: article
metadata_visibility: show
creators_name: Vasiliadou, R
creators_name: Dimov, N
creators_name: Szita, N
creators_name: Jordan, SF
creators_name: Lane, N
title: Possible mechanisms of CO₂ reduction by H₂ via prebiotic vectorial electrochemistry
ispublished: pub
divisions: UCL
divisions: B02
divisions: C08
divisions: D09
divisions: F99
divisions: B04
divisions: C05
divisions: F47
keywords: CO2 reduction, origin of life, vectorial chemistry, energy-converting hydrogenase, alkaline hydrothermal vents, microfluidic reactor
note: Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original
author and source are credited.
abstract: Methanogens are putatively ancestral autotrophs that reduce CO2 with H2 to form biomass using a membrane-bound, proton-motive Fe(Ni)S protein called the energy-converting hydrogenase (Ech). At the origin of life, geologically sustained H+ gradients across inorganic barriers containing Fe(Ni)S minerals could theoretically have driven CO2 reduction by H2 through vectorial chemistry in a similar way to Ech. pH modulation of the redox potentials of H2, CO2 and Fe(Ni)S minerals could in principle enable an otherwise endergonic reaction. Here, we analyse whether vectorial electrochemistry can facilitate the reduction of CO2 by H2 under alkaline hydrothermal conditions using a microfluidic reactor. We present pilot data showing that steep pH gradients of approximately 5 pH units can be sustained over greater than 5 h across Fe(Ni)S barriers, with H+-flux across the barrier about two million-fold faster than OH–-flux. This high flux produces a calculated 3-pH unit-gradient (equating to 180 mV) across single approximately 25-nm Fe(Ni)S nanocrystals, which is close to that required to reduce CO2. However, the poor solubility of H2 at atmospheric pressure limits CO2 reduction by H2, explaining why organic synthesis has so far proved elusive in our reactor. Higher H2 concentration will be needed in future to facilitate CO2 reduction through prebiotic vectorial electrochemistry.
date: 2019-12
date_type: published
publisher: The Royal Society
official_url: https://doi.org/10.1098/rsfs.2019.0073
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 1710073
doi: 10.1098/rsfs.2019.0073
lyricists_name: Jordan, Sean
lyricists_name: Lane, Nicholas
lyricists_name: Szita, Nicolas
lyricists_id: SJORD72
lyricists_id: NJLAN31
lyricists_id: NSZIT68
actors_name: Kalinowski, Damian
actors_id: DKALI47
actors_role: owner
full_text_status: public
publication: Interface Focus
volume: 9
number: 6
issn: 2042-8901
citation:        Vasiliadou, R;    Dimov, N;    Szita, N;    Jordan, SF;    Lane, N;      (2019)    Possible mechanisms of CO₂ reduction by H₂ via prebiotic vectorial electrochemistry.                   Interface Focus , 9  (6)      10.1098/rsfs.2019.0073 <https://doi.org/10.1098/rsfs.2019.0073>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10084147/1/Jordan_Possible%20mechanisms%20of%20CO%E2%82%82%20reduction%20by%20H%E2%82%82%20via%20prebiotic%20vectorial%20electrochemistry_VoR.pdf