Hydrogen Production and Conversion

While the goal of a synthetic WOC has yet to be achieved, the selected examples given above show that great progress has been made in this field over a relatively short timescale. 

Nature s concept of hydrogen conversion - or the reverse process of hydrogen generation - at these highly optimized catalytic centers is based on a heterolytic mechanism  

4 Molecular Concepts of Water Splitting Nature s Approach 

These features demonstrate how important it is to study and understand hydrogenase structure and function when designing biomimetic (or bioinspired) systems for efficient hydrogen generation or utilization. This section will give insight into this class of enzymes. 

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These metals, when deposited on the E-cat catalyst, increase coke and gas-making tendencies of the catalyst. They cause dehydrogenation reactions, which increase hydrogen production and decrease gasoline yields. Vanadium can also destroy the zeolite activity and thus lead to lower conversion. The deleterious effects of these metals also depend on the regenerator temperature the rate of deactivation of a metal-laden catalyst increases as the regenerator temperature increases. 

The hydrogenase may be electrically wired with different semiconductors, metals and conducting materials as an electrode. This property of the enzyme is successfully used in design of different biomolecular device for renewable energy production and conversion systems based on molecular hydrogen as intermediate energy carrier. In many cases... 

At a very optimistic conversion efficiency of 10 % and a price for H2 of 15 per GJ only 10 worth of H2/m2/year would be obtained thus severely constraining construction and operational expenditures. Obviously, the situation worsens if conversion efficiencies are lower. In spite of the critical importance of this consideration, relatively few studies on photobiological hydrogen production report conversion efficiencies, and when these are reported they typically fall well below 1 % (i.e. < 1 HVmVyear). 

Filamentous cyanobacteria have been used in bioreactors for the photobiological conversion of water to hydrogen. However, the conversion efficiencies achieved are low because of the competing processes of hydrogen production and consumption within... 

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