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> In fact, he said, the new catalyst is 1,000 times faster than noble-metal catalysts — and about 20 times cheaper.

> The combination of water and the ionic liquid makes a co-catalyst that preserves the catalyst’s active sites under the harsh reduction reaction conditions,

No mention of efficiency compared to photovoltaic cells.



There are some efficiency numbers in the abstract of the "Nanostructured transition metal dichalcogenide electrocatalysts for CO2 reduction in ionic liquid." article:

Conversion of carbon dioxide (CO2) into fuels is an attractive solution to many energy and environmental challenges. However, the chemical inertness of CO2 renders many electrochemical and photochemical conversion processes inefficient. We report a transition metal dichalcogenide nanoarchitecture for catalytic electrochemical CO2 conversion to carbon monoxide (CO) in an ionic liquid. We found that tungsten diselenide nanoflakes show a current density of 18.95 milliamperes per square centimeter, CO faradaic efficiency of 24%, and CO formation turnover frequency of 0.28 per second at a low overpotential of 54 millivolts. We also applied this catalyst in a light-harvesting artificial leaf platform that concurrently oxidized water in the absence of any external potential.

Copyright © 2016, American Association for the Advancement of Science.


The efficiency is around 4%, as in Figure 2 from the paper. SFE is solar-to-fuel efficiency.

From the paper, " We also calculated the solar-to-fuel conversion efficiency (SFE) for our photochemical process (Fig. 2C), obtaining a value of ~4.6% limited by the maximum efficiency of the PV-a-si-3jn cell (~6.0%) (13, 20). This SFE is higher than that of the water-splitting reaction (~2.5%) previously measured using an identical triple-junction photovoltaic (PV-a-si-3jn) cell (20). "

https://d2ufo47lrtsv5s.cloudfront.net/content/sci/353/6298/4...


For comparison, most crop plants get 1-2% solar to biomass efficiency on the high end.


I'm more interested with comparison to plants harvested for biodiesel.


The key difference in my opinion is that this process would not be competing for land with existing crops. We could do both.


Yes it would, sun rays only hit the ground once.


There are plenty of areas of this planet where plants don't grow because the climate is too harsh (not enough water and/or extreme temperatures)


I understand your point, but this system also requires water, and therefore does compete at that point as well. Higher temperatures also have a negative effect at the efficiency of solar panels, but they are indeed a lot more resistant (typically lower temperature=better efficiency for solar panels).


Cold, water, sunlight, no crops, existing infrastructure for moving fuels. Alaska? There's even high CO2 there from wood stoves (Alaska is 4th per-capita).

http://www.eia.gov/environment/emissions/state/analysis/


Alaska is so enormous and sparsely populated that I doubt much that the residents do will have a significant impact on the ambient CO2 levels, compared to a state like Texas or California, which are about 80 and 250 times more population dense for their size.

I agree with all the rest of your factors, though high CO2 is likely not a mark in Alaska's favor. My main concerns with Alaska would be suitably large cleared land area to collect sunlight without damaging the environment, and not having panels get covered in snow in the winter.


I wonder if they could use sea water?


Really, you can't think of any places where there's sunlight and water but no crops are grown?




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