[Rebel_Ace]

"...carbon, copper and nitrogen and applied voltage..."

In other words, the process requires energy.
Not surprising, it's the law of physics.
Where will that energy come from? Will it be cost effective?

I think you miss an essential point. You can think of the ethanol as "storing" the energy from the "applied voltage".

What are the biggest issues with the so called "renewable" forms of energy, like Wind and Solar? They don't work all the time. They are not located where the energy is needed. How do you "store" extra wind? How do you "store" sunlight for nighttime? How do you "transport" wind energy from the plains to the cities where it's needed?

So, imagine this catalyst process where the "applied current" comes from a bank of solar cells. The burnable ethanol is literally a way to "store" the energy for later.

As long as you are not doing something as stupid as burning Natural Gas or Coal, to turn a turbine to make electricity to power the catalytic process, you can consider it a "net gain" in stored energy, which can be bottled and transported where needed.

[BitWielder1]

You're right that it makes no sense burning something else to make electricity to make ethanol for energy purposes.
That leaves solar.
The question of efficiency is still legitimate.
Can they make, install and maintain a field of ethanol generating solar panels that are more cost effective than planting and processing corn?
Or drilling for oil.

[Ozark Tom]

Mix nitrate fertilizer with water and the mixture gets cold, energy is required for the process. The nano-chemistry may allow thermal energy to supply part or most of the energy needed, if the nanotechnology can extract electrical energy from thermal potential.

Chlorophyll produces electrical charges from light, stores sufficient electrical energy to drive a chemical process, and coordinates the combining of electrical potential and chemistry processes to create carbohydrates.