TY - JOUR

T1 - Abiogenesis and photostimulated heterogeneous reactions in the interstellar medium and on primitive earth

T2 - Relevance to the genesis of life

AU - Emeline, A. V.

AU - Otroshchenko, V. A.

AU - Ryabchuk, V. K.

AU - Serpone, N.

PY - 2003/1/31

Y1 - 2003/1/31

N2 - Heterogeneous reactions occur on solid photocatalyst particles of semiconductors and dielectric materials. When irradiated with suitable UV/visible light energy these particles generate electrons and holes, which on the surface are poised to undergo reductive and oxidative chemistry with a variety of organics and light gases. Various such particles have been identified in Interstellar Space, specifically in molecular-dust clouds, comets and meteorites. In this article, we examine briefly the nature of these dust clouds and then describe some basic aspects of heterogeneous photocatalysis, a methodology that has been shown useful in transforming organic substrates into smaller molecules and in the synthesis of potential biomolecules. Various types of gas/solid heterogeneous reactions involving mostly small molecules in gas/solid systems find a relationship to abiogenesis. For example, the decomposition of H2O and CO2 in the presence of CH 4 yields H2CO; methane is photoconverted into ethane, propane, ethylene and other hydrocarbons and is photooxidized to alcohols and carbon dioxide; photofixation of CO2 occurs to yield formaldehyde, formic acid, methanol and methane; and finally photofixation of molecular nitrogen N2 can take place to produce NH3 and N 2H2. Not least is the synthesis of glycine, alanine, aspartic acid and serine from CH4 and NH3 over platinized titania. The relevance of heterogeneous photocatalysis to abiogenesis is discussed. It is argued that the physical conditions available in the interstellar medium are propitious to generate such biomolecules as amino acids and others, albeit this assertion necessitates laboratory simulations. Recent laboratory experiments involving very simple photoinduced processes are encouraging.

AB - Heterogeneous reactions occur on solid photocatalyst particles of semiconductors and dielectric materials. When irradiated with suitable UV/visible light energy these particles generate electrons and holes, which on the surface are poised to undergo reductive and oxidative chemistry with a variety of organics and light gases. Various such particles have been identified in Interstellar Space, specifically in molecular-dust clouds, comets and meteorites. In this article, we examine briefly the nature of these dust clouds and then describe some basic aspects of heterogeneous photocatalysis, a methodology that has been shown useful in transforming organic substrates into smaller molecules and in the synthesis of potential biomolecules. Various types of gas/solid heterogeneous reactions involving mostly small molecules in gas/solid systems find a relationship to abiogenesis. For example, the decomposition of H2O and CO2 in the presence of CH 4 yields H2CO; methane is photoconverted into ethane, propane, ethylene and other hydrocarbons and is photooxidized to alcohols and carbon dioxide; photofixation of CO2 occurs to yield formaldehyde, formic acid, methanol and methane; and finally photofixation of molecular nitrogen N2 can take place to produce NH3 and N 2H2. Not least is the synthesis of glycine, alanine, aspartic acid and serine from CH4 and NH3 over platinized titania. The relevance of heterogeneous photocatalysis to abiogenesis is discussed. It is argued that the physical conditions available in the interstellar medium are propitious to generate such biomolecules as amino acids and others, albeit this assertion necessitates laboratory simulations. Recent laboratory experiments involving very simple photoinduced processes are encouraging.

KW - Abiogenesis

KW - Genesis of life

KW - Heterogeneous photocatalysis

KW - Interstellar medium

KW - Interstellar space

UR - http://www.scopus.com/inward/record.url?scp=0242486850&partnerID=8YFLogxK

U2 - 10.1016/S1389-5567(02)00039-4

DO - 10.1016/S1389-5567(02)00039-4

M3 - Review article

AN - SCOPUS:0242486850

VL - 3

SP - 203

EP - 224

JO - Journal of Photochemistry and Photobiology C: Photochemistry Reviews

JF - Journal of Photochemistry and Photobiology C: Photochemistry Reviews

SN - 1389-5567

IS - 3

ER -