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CO2 Reduction

  I will transcribe this from a chemical engineering journal*1) for my own understanding.

 Let's consider the reaction of a plant that reduces CO2 to oxygen. First, a water molecule is "photo-oxidized" to produce one mole of oxygen molecules, and at the same time, two moles of "hydride" (H-) are produced, and these two moles of "hydride" reduce CO2. In short, the equation for the photo-oxidation of water is ② from ①.


H- = H+ + 2e-   ①


2H2O+4hν → O2+4e- + 4H+ → O2+2H- + 2H+   ②


The "conversion of photons (hν) to electron energy (e-)" in equation ① above is achieved by the catalytic function of chlorophyll in plants. Artificially, it is done by photocatalysts. The author of this article has succeeded in "CO2 reduction to methanol" *2). The principle is the reduction of CO2 by 3 moles of "hydride" ③.


3H- + CO2 + 3H+ → CH3-OH (methanol) + H2O   ③


*1)Production Engineering Journal, Chemical Equipment, April 2021, p63

*2)Y. Matsushita, A. Murata, T. Murata, H. Tanibata, T. Suzuki, T. Ichimura, "Photosynthesis of High-Value Added Compounds in Microreaction System", Micro Total Analysis System 2007 2, 1462-1464(2007), 1

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