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Carbon Capture

Discussion in 'Earth and Environmental Science' started by classic33, 13 Jun 2017.

  1. classic33

    classic33 Veteran Geek

    Cheap catalysts turn sunlight and carbon dioxide into fuel
    Thanks to a new catalyst, sunlight has been converted into chemical energy with a record
    13.4% efficiency.
    By Robert Service Jun. 6, 2017 , 4:00 PM

    Scientists have long dreamed of mimicking photosynthesis, by using the energy in sunlight to knit together hydrocarbon fuels from carbon dioxide (CO2) and water. Now, a cheap new chemical catalyst has carried out part of that process with record efficiency, using electricity from a solar cell to split CO2 into energy-rich carbon monoxide (CO) and oxygen. The conversion isn’t yet efficient enough to compete with fossil fuels like gasoline. But it could one day lead to methods for making essentially unlimited amounts of liquid fuels from sunlight, water, and CO2, the chief culprit in global warming.

    The new work is “a very nice result,” says John Turner, a renewable fuels expert at the National Renewable Energy Laboratory in Golden, Colorado.

    The transformation begins when CO2 is broken down into oxygen and CO, the latter of which can be combined with hydrogen to make a variety of hydrocarbon fuels. Adding four hydrogen atoms, for example, creates methanol, a liquid fuel that can power cars. Over the last 2 decades, researchers have discovered a number of catalysts that enable that first step and split CO2 when the gas is bubbled up through water in the presence of an electric current. One of the best studied is a cheap, plentiful mix of copper and oxygen called copper oxide. The trouble is that the catalyst splits more water than it does CO2, making molecular hydrogen (H2), a less energy-rich compound, says Michael Graetzel, a chemist at the Swiss Federal Institute of Technology in Lausanne, whose group has long studied these CO2-splitting catalysts.

    Last year, Marcel Schreier, one of Graetzel’s graduate students, was looking into the details of how copper oxide catalysts work. He put a layer of them on a tin oxide–based electrode, which fed electrons to a beaker containing water and dissolved CO2. Instead of splitting mostly water—like the copper oxide catalyst—the new catalyst generated almost pure CO. “It was a discovery made by serendipity,” Graetzel says.

    A bright idea
    A new catalyst made from copper and tin oxides uses electric current from a solar cell to split water (H2O) and carbon dioxide (CO2), creating energy-rich carbon monoxide (CO) that can be further refined into liquid fuels.
    The tin, Graetzel adds, seems to deactivate the catalytic hot spots that help split the water. As a result, almost all the electric current went into making the more desirable CO. Armed with the new insight, Graetzel’s team sought to speed up the catalyst’s work. To do so, they remade their electrode from copper oxide nanowires, which have a high surface area for carrying out the CO2-breaking reaction, and topped them with a single atom-thick layer of tin. As Graetzel’s team reports this week in Nature Energy, the strategy worked, converting 90% of the CO2 molecules into CO, with hydrogen and other byproducts making up the rest. They also hooked their setup to a solar cell and showed that a record 13.4% of the energy in the captured sunlight was converted into the CO’s chemical bonds. That’s far better than plants, which store energy with about 1% efficiency, and even tops recent hybrid approachesthat combine catalysts with microbes to generate fuel.

    Nate Lewis, a chemist at the California Institute of Technology in Pasadena, says the new result comes on the heels of other recent improvements that use different catalysts to turn CO2 into fuels. “Together, they show we’re making progress,” Lewis says. But he also cautions that current efforts to turn CO2 into fuel remain squarely in the realm of basic research, because they can’t generate fuel at a price anywhere near to that of refining oil.

    Still, exploding supplies of renewable electricity now occasionally generate more power than the grid can handle. So scientists are looking for a viable way to store the excess electricity. That’s likely to drive further progress in storing energy in chemical fuels, Graetzel says.

    beanz likes this.
  2. beanz

    beanz Staff Member Staff Member

    I hope this has an application to the generation of electricity. Cheaper, abundent energy is such a tantalising prospect. I long for the day when generating and storing electricity becomes really cheap.

    At present, there's only so much people can do to reduce electricity consumption in their homes. I'm a real energy miser nowadays, having changed to low-energy lighting, switched off everything I possibly can that would otherwise be on standby, stopped using the satellite box to watch channels that I can get anyway on my smart tv, only filling the kettle with the amount of water needed and doing so ahead of time so that it warms naturally to room temperature before the kettle is switched on (reducing kettle run time) etc. And yet, although we've managed (by turning the thermostat down and being more bullish about when we have the central heating on) to reduce our gas usage by over 10% in the last 12 months, our electricity consumption figure has remained stubbornly about the same. And thanks to recent price hikes, our forecast for the coming 12 months says we're going to be charged a fair bit more for using the same amount of electricity as we did in the past 12.

    Any development that eventually had implications which led to cheaper electricity would be marvellous. :)
    Last edited: 15 Jun 2017
  3. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    I'm a bit sceptical about this, though like the idea and think it's worth chasing. It seems to work on pure CO2, without really saying how you would get pure CO2 to feed the system. Also '13.4% of the energy in the captured sunlight was converted into the CO’s chemical bonds' don't sound like a huge percentage, surely current batteries do much better than that. Also no mention of how much it costs to make and maintain.

    So an interesting idea but I can't see it revolutionising the world any time soon, if ever.
  4. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Indeed, this has always been the case. It's not a bad thing to try and reduce your load, if nothing else to save a bit of money. Though it has a much better effect with changes to the technology that runs our electronic devices than how we use them. A switch from CRT to LED flat screens probably saves you more money than all the things you could do to reduce your supply, keeping the TV turned off saves even more :wink:. Same is true of energy efficient fridges, freezers, cooker and boilers. In the future smart devices like how water boilers that work when demand is low, batteries in houses that cache energy when it's cheap and even better low power devices will reduce demand much more than being prudent.
  5. beanz

    beanz Staff Member Staff Member

    Yes, wouldn't go back to a CRT for anything, and especially given the cost of energy now. It pleases me that with a 49" LED tv, low-energy lights, and just essential things like the fridge freezer ticking over in the background, our home energy monitor remains firmly in the green. The real problem is things like washing and drying clothes where despite advances in detergents allowing lower temperature washing plus us buying an energy-efficient washer and using an outdoor clothes dryer whenever we can, there's not much more we can do to economise there - the energy monitor is hard over in the red each time we do the washing. I would guess that's a major contributor to our electricity bill.

    I probably get overenthusiastic about breakthroughs in fuel conversion efficiency as a result. It is such an important area of research though.
  6. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Yer, I feel there are some things like washing machines that will always use quite a bit of energy, though there are people working to reduce even them. Hopefully we will get to the point where there are local cost effective generators like solar and vertical wind turbines we can add to homes that can power these devices and reducing the load on the networks.

    I still think the main way to go is to convert the supply network to be 100% renewable, after that hopefully the maintenance costs will drastically fall, after all the main cost at the moment is putting in the infrastructure. i.e. offshore wind is expensive because you have to put in the cables, poles and turbines but replacing the turbines, patching up cables and replacing the odd pole costs a lot less. Along with things like the new Tesla solar roofs that are supposed to last longer than a house! Once we have this sort of technology everywhere then electricity will cost next to nothing and we will still get improvements with energy efficiency too.

    It's coming but is going to take a bit of time to roll out to everyone, though as we showed with roads, cars and petrol supply we can roll these things out fairly quickly when we want to. Back then the governments helped out a lot, in things like building the roads. Imagine how much longer it would have taken for cars to catch on if we had to wait for private companies to pay for the road we use. So we need to keep pressure on the governments to keep up the grants, feed in tariffs and such things so we get there as soon as possible.
  7. classic33

    classic33 Veteran Geek

    The original aim was to improve on nature
    "find a cost-effective way to produce fuels from sunlight ten times more efficiently than plants. Since 2015, the JCAP mission has focused on producing fuels from carbon dioxide, specifically on the discovery of new non-molecular and non-biological catalysts that make carbon-containing fuels from carbon dioxide, water, and light or electricity."

  8. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member


    This is a good insight into what's needed to actually capture carbon out of the air. It's good to see we are refining the process and making progress. I do think part of the solution will eventually need some sort of recapture of the carbon we have already put into the atmosphere.

    That still seems like an expensive solution but hopefully if they keep optimising the system they can get efficiency up.