[freebeard]

Thanks. That is interesting; I'd seen the headline and 'surfed' right past. It seems to be a combination of strategies — the transition metal dichalcogenides as catalysts

In fact, he said, the new catalyst is 1,000 times faster than noble-metal catalysts—and about 20 times cheaper.
Read more at: Breakthrough solar cell captures carbon dioxide and sunlight, produces burnable fuel

having a reactor that has differing solar chemistries on the anode and cathode

The UIC artificial leaf consists of two silicon triple-junction photovoltaic cells of 18 square centimeters to harvest light; the tungsten diselenide and ionic liquid co-catalyst system on the cathode side; and cobalt oxide in potassium phosphate electrolyte on the anode side.
Read more at: Breakthrough solar cell captures carbon dioxide and sunlight, produces burnable fuel

....and an engineering fix to a show-stopper

"The active sites of the catalyst get poisoned and oxidized," Salehi-Khojin said. The breakthrough, he said, was to use an ionic fluid called ethyl-methyl-imidazolium tetrafluoroborate, mixed 50-50 with water.

"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," Salehi-Khojin said.
Read more at: Breakthrough solar cell captures carbon dioxide and sunlight, produces burnable fuel

So— good on them. They mention small-scale; I wonder if they are thinking about 3D printing cells the proportions of a Maple leaf. If they did they could use the fluttering of the leaf in it's Karmann vortex shedding to pump the liquid fuel around.

How do they interface the two electrolytes?