In what way? Energy production? I believe there are quite some breakthrougs required for this to compete with cheap solar panels.

Direct solar-to-chemical systems like this can be more efficient in theory because they cut out the middleman (electricity storage and conversion), but in practice, they're often less mature and have lower overall efficiency right now compared to established solar-electric-chemical setups

I'm also wondering how it compares to the efficiency of things like "grass" and "trees", which also convert sunlight into very useful things.

Agreed: this is the key question. One effort I follow in this direction is Terraform Industries[0] who are building exactly this type of system.

Their approach is PV + DCC (Direct Carbon Capture) and then simple carbohydrate synthesis, with the goal of establishing standalone autonomous systems that can generate valuable resources on their own in remote areas with ample sunlight.

They have a great blog where they go through their motivation for the approach from first principles [1].

[0]: https://terraformindustries.com/ [1]: https://terraformindustries.wordpress.com/home/

After following the literature down several different rabbit holes, I found this argument in some of the supplementary figures on that tree that seems to address your question:

> "Supplementary Note 1 | Advantages of PEC hydrocarbon synthesis.

"In general, PEC systems have the potential to combine the performance of wired PV-electrolysis (PV-E) systems with the simplicity of photocatalytic (PC) systems. PV-E is an established technology, which can take advantage of commercial solar cell modules with light harvesting efficiencies above 20% 24 and state-of-the-art gas diffusion electrolysers operating at high current densities above 1 A cm-2.25 However, PV-E assemblies require additional components including reactors, membranes, pumps, corrosive electrolytes, external cables and control electronics, increasing the overall system complexity and associated cost.26,27"

"On the other hand, PC powders provide an inexpensive alternative to PV-E, since light absorber particles and any necessary catalysts are dispersed in solution, which greatly minimises the overall system complexity. However, wide band gaps and charge recombination often limits solar-to-hydrogen conversion efficiencies to below 1%.28 While a homogeneous dispersion of the light absorber and catalyst can increase reactivity, this also poses challenges for the subsequent separation of all components and products from the reaction mixture."

"Accordingly, PEC artificial leaves provide a balance between PV-E and PC approaches in terms of complexity, cost and performance, by integrating state-of-the-art semiconductors and catalysts into a single compact panel. These PEC devices can perform reactions beyond water splitting (e.g., CO2 reduction to C1 products, or the light-driven C2 hydrocarbon and organic synthesis introduced here), while allowing product separation between the anodic and cathodic sides. This intrinsic design advantage is demonstrated by lightweight PEC systems using 15-fold less material than conventional solar panels, which combine the high performance of wired systems with the high activity per gram of photocatalyst nanoparticles.29 This applicability and potential of PEC-based fuel production also translates to hydrocarbon synthesis. In addition, direct light-driven hydrocarbon synthesis is carbon neutral, avoiding the energy-intensive Fischer-Tropsch process for indirect hydrocarbon synthesis from syngas (H2 + CO)."

Practically speaking the catalysts in these processes have relatively short lifetimes, so you'd want to incorporate an efficient catalyst regeneration process into the production pipeline, i.e. you might only get 16-128 hours of efficient production before catalyst regeneration is required so that needs to be built into any commercial process. So if you can design a catalyst that's easy to regenerate, that's very important.

Source material with nice pictures of the copper nanoflowers:

https://static-content.springer.com/esm/art%3A10.1038%2Fs419...

Efficiency is likely much lower than solar panels, however, solar panels are expensive and complicated (chemically) to manufacture. Teaching plans to make stuff for us is a better long term solution as we can just grow the plants.

You don't want another new JavaScript framework instead?

Speaking of which, it feels like we are overdue for the next big one. Is it actually slowing down?

Everybody just went head first into AI?

Biology is stunningly efficient, but it's hard to optimize further. To get really high yields you usually need industrial processes.

>I'm in my early thirties and I feel like i've heard about an "artificial leaf" every five years for the last fifteen.

You have a good memory. Most people don't, so the ruse of living in a world with amazing breakthroughs works really well with most people.

Many politicians are more interested in protecting the coal, oil, and gas industries. Renewable energy and methods of extracting carbon from the atmosphere are the last things they want.

The pragmatic answer is that it is probably a better spend of time to innovate tech that circumvents politics than to spend time winning politics.

I think the reality is there is no saving anything. Only surviving as long as we can. Why dump billions into an impossible goal of saving when we could invest in survival? I hope I’m wrong but anyone that knows anything about investments knows that there’s a point where you need to cut your losses

Natural habitats has been destroyed by agriculture.

In the US 10-20% of agricultural land is used to produce chemicals like starch, sugar or biofuels, if we could use less land to produce these it would be great.

Photovoltaics could be up 100x more efficient in producing these chemicals.

This technology could free agricultural land back to natural habitats.

I'm pretty glad that when we've chopped down all our forests, we'll have mechanical leaves as a backup plan. Having the means to generate enough electricity to take oxygen out of the atmosphere could be useful.

The device makes ethane and ethylene, oversimplify it's just natural gas. You must put it inside a huge petrochemical refinery to join some of them to make plastic or fuel.