Photochemical splitting carbon dioxide

From the point of view of organic synthesis, the overall process consists of the formation of carbohydrates (CH20) by the reduction of carbon dioxide. The essence of the process is the use of photochemical energy to split water and concomitantly to reduce C02. Many proteins and small molecules are involved in photosynthetic machinery. Inorganic species are in the centre of photosynthesis as pigments in light harvesting, substrates, products, catalysts, and electron transfer mediators. 

The essence of natural photosynthesis is the use of photochemical energy to split water and reduce CO2. Molecular oxygen is evolved in the reaction, although it appears at an earlier stage in the sequence of reactions than the reduction of carbon dioxide. Photochemical processes produce compounds of high chemical potential, which can drive a multistep synthetic sequence from CO2 to carbohydrate in a cyclic way. Reaction (16) is quite endoergic and thus thermodynamically very improbable in the dark (AG° = 522 kJ per mole of CO2 converted). Production of one molecule of oxygen and concomitant conversion of one molecule of carbon dioxide require the transfer of four electrons ... 

The other paper appearing in 1937 dealt with the sensitization of photochemical reactions in the surface by the adsorption of ions of metals. The effect means that the course of a reaction in a surface film may be completely altered by the adsorption of traces of heavy metal ions. Mitchell, Rideal, and Schulman (73) showed that minute quantities of nickel or copper ions may be enough to change or even to initiate a surface reaction. In the decomposition, for example, of films of a-hydroxy-stearic acid on 0.01 N HCl, under the action of radiation, carbon dioxide is apparently split off from the molecule. If, however, the radiation has a... 

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