Hydrogen production limiting factors

Photobiological hydrogen production is a theoretically more efficient process, but significant fundamental molecular research is needed to identify and improve the limiting factors in order to evaluate fully this approach for hydrogen production. 

Results at true differential conversions have demonstrated that the intrinsic rate of COj hydrogenation is unaffected by the presence of Pd, whether it is incorporated by impregnation or added in a physical mixture, in the absence of water. For catalytic conversion of CO2 to methanol, a limiting factor at industrially useful yields is the high concentration of product water the effect of which can be ameliorated to some extent by Pd probably due to hydrogen spillover. 

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