Harvard University School of Engineering and Applied Sciences  Environmental Sciences and
Engineering (ESE) Program
Atmospheric Sciences Seminar
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Current Projects
 
  • Phase Transitions of
       Atmospheric Particles


     - Crystallization of SNAP
        Particles

     - 1×3TDMA
     - Atmospheric Nanoparticles
     - Modeling Aerosol Phase
        Transitions and Radiative
        Effects


  • Dissolution and
       Precipitation of Minerals
       in Aquatic Environments

     
  • Chemical Oxidation
       Reactions and Hydrophobic
       -to-Hydrophilic Aging of OAs


     - Aerodyne AMS analysis
     - CCN properties of OAs

  • Origins of Life:
       Mineral Surface Photo-
       Electrochemistry


  • Harvard Environmental Chamber

    AMAZE-08


    Closed Projects

      - Crystallization of Sulfate and
       Nitrate Coatings on
       Tropospheric Mineral Particles

     
      - Tropospheric Mineral
       Particles as Ice Nuclei

     
      - Building Structures at
       the Nanoscale



     

     

    Mineral Surface Photoelectrochemistry to Reduce Inorganic Carbon and Form the Prebiotic Soup

    How did life begin?

    4 billion years ago

    We are investigating mineral surface photoelectrochemistry as a pathway to reduce inorganic carbon and form a prebiotic soup of organic precursors to life. Basic project questions are: What CxHyOzSaNb molecular products result from CO and CO2 photoreduction over semiconductor supports? What important synthesis reactions relevant to prebiotic chemistry, which are otherwise "no go" via thermal pathways, become possible through semiconductor photocatalysis? Relevant semiconductors for early Earth include ZnS, TiO2, ZnO, and MnS. The list expands for chemistry occurring on interstellar dust, which may have seeded organic molecules into the prebiotic soup.

    From the five known mechanisms by which autotrophic organisms fix carbon, a reductive tricarboxylic acid (rTCA) cycle has been proposed as the most plausible metabolic pathway of CO2 fixation at the time life originated. A nonenzymatic rTCA cycle might have functioned as an autocatalytic network of chemical reactions able to provide and self-sustain the biosynthetic pathways essential for life to originate. For these reasons, we are currently studying the kinetics of some reactions of the reverse Krebs cycle driven by mineral photochemistry, and the thermal competition pathways. We intend to understand if this chemical cycle could have been related to the origin of prebiotic metabolism.

    photochem cell

    Photochem_setup

    Photochemical setup. 500 mL reaction vessel with water jacket around it. In the center a quartz immersion well holds a turned on UV lamp (wavelength 200 to 400 nm). Sphalerite (ZnS, white) suspension is stirred continuosly.

    We are grateful for support received from the Harvard Origins of Life Initiative and the NASA Exobiology Program.

     

    Link

    The Harvard origins of life initiative

    People Involved

    Publications

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