TY - JOUR
T1 - DFT study of the reduction reaction of calcium perchlorate on olivine surface
T2 - Implications to formation of Martian’s regolith
AU - Escamilla-Roa, Elizabeth
AU - Zorzano, María-Paz
AU - Martin-Torres, Javier
AU - Hernández-Laguna, Alfonso
AU - Saínz-Díaz, C. Ignacio
N1 - Authors would like to acknowledge the contribution of the European COST Action CA17120 supported by the EU Framework Programme Horizon 2020, and the Spanish MINECO projects CGL2014-55230-R, FIS2016-77692-C2, PCIN-2017-098. MPZ acknowledges the partial support of the Spanish State Research Agency (AEI) Project No.MDM-2017-0737. E. E. acknowledges to Rafael Esteso for his help with the Graphical Abstract
PY - 2020/5/15
Y1 - 2020/5/15
N2 - Perchlorates have been found widespread on the surface of Mars, their origin and degradation pathways are not understood to date yet. We investigate here, from a theoretical point of view, the potential redox processes that take place in the interaction of Martian minerals such as olivine, with anhydrous and hydrated perchlorates. For this theoretical study, we take as mineral substrate the (1 0 0) surface of forsterite and calcium perchlorate salt as adsorbate. Our DFT calculations suggests a reduction pathway to chlorate and chlorite. When the perchlorate has more than 4 water molecules, this mechanism, which does not require high-temperature or high energy sources, results in parallel with the oxidation of the mineral surface, forming magnesium peroxide, MgO2, and in the formation of ClO3, which through photolysis is known to form ClO-O2. Because of the high UV irradiance that reaches the surface of Mars, this may be a source of O2 on Mars. Our results suggest that this process may be a natural removal pathway for perchlorates from the Martian regolith, which in the presence of atmospheric water for salt hydration, can furthermore lead to the production of oxygen. This mechanism may thus have implications on the present and future habitability of the Martian surface.
AB - Perchlorates have been found widespread on the surface of Mars, their origin and degradation pathways are not understood to date yet. We investigate here, from a theoretical point of view, the potential redox processes that take place in the interaction of Martian minerals such as olivine, with anhydrous and hydrated perchlorates. For this theoretical study, we take as mineral substrate the (1 0 0) surface of forsterite and calcium perchlorate salt as adsorbate. Our DFT calculations suggests a reduction pathway to chlorate and chlorite. When the perchlorate has more than 4 water molecules, this mechanism, which does not require high-temperature or high energy sources, results in parallel with the oxidation of the mineral surface, forming magnesium peroxide, MgO2, and in the formation of ClO3, which through photolysis is known to form ClO-O2. Because of the high UV irradiance that reaches the surface of Mars, this may be a source of O2 on Mars. Our results suggest that this process may be a natural removal pathway for perchlorates from the Martian regolith, which in the presence of atmospheric water for salt hydration, can furthermore lead to the production of oxygen. This mechanism may thus have implications on the present and future habitability of the Martian surface.
KW - Calcium perchlorate
KW - Reduction
KW - Oxygen
KW - Water
KW - Mars
KW - Chlorate
KW - Chlorite
KW - Ozone
KW - Magnesium peroxide
KW - Regolith
KW - (1 0 0) forsterite surface
KW - Olivine
KW - Chemisorption
KW - Physisorption
KW - Redox
KW - Infrared spectroscopy
KW - Density Functional Theory (DFT)
UR - http://ltu.diva-portal.org/smash/record.jsf?pid=diva2%3A1393002&dswid=-7557
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85079320511&partnerID=MN8TOARS
U2 - 10.1016/j.apsusc.2020.145634
DO - 10.1016/j.apsusc.2020.145634
M3 - Article
VL - 512
JO - Applied Surface Science
JF - Applied Surface Science
SN - 0169-4332
M1 - 145634
ER -