Advanced Materials to Combat Climate Change
We are screwed.
Millions of people around the world are suffering from the effects of extreme disasters by climate change — from droughts in sub-Saharan Africa to devastating tropical storms sweeping across Southeast Asia, the Caribbean and the Pacific.
Snap out of it. Yes, you!
Most of us spend our time on earth trying to survive, fulfill our basic needs and this leaves us consumed. We’re all busy. But if you just step away from the madness which is [your life] for a second, you’ll realize that our planet is starting to deplete + will soon look like this:
Hell yeah, that’s scary. What are we gonna do? Move to Mars? Maybe. But we can let Elon Musk handle that.
There is hope.
Instead, we can use these fancy materials called Nanomaterials which are materials made up of units that are each thousands of times smaller than the thickness of a human hair.
Carbon dioxide(C02) is the most dominating greenhouse gas. We need to control the amount of CO2 in order to overcome excessive, environmentally harmful carbon dioxide emissions and control the carbon balance. The objective is to use nanomaterials which can efficiently use carbon dioxide from the air, capture toxic pollutants from water. Then, we take this captured CO2 and turn it into useful products.
Sounds easy right? It’s not as easy as it may seem but let’s understand how this can be possible.
Carbon dioxide can be converted into plastics, fabrics, and other useful products through artificial photosynthesis.
Plants are terrific at using energy from the sun to convert carbon dioxide and water into carbohydrates for fuel, we can replicate this process to make clean fuels and other products.
We can use catalysts which are substances that speed up a chemical reaction but are not consumed by the reaction.
Using catalysts to turn carbon dioxide and water into chemical compounds containing one, two, three, or four carbon atoms with more than 99 percent efficiency. The process is highly energy-efficient and does not require much electricity.
The carbon compounds can be used as building blocks to make useful materials. The number of carbon atoms in the end product depends on the catalyst used and the reaction conditions. The longer carbon chains are more valuable and could serve as the building blocks of plastics.
Basic concepts of CO2 reduction:
CO2 molecule has a linear structure and is highly stable. It also has muliple electron transformations. For the reduction of CO2 into other useful compounds, high amount of energy is required because of its low energy levels.
Electrochemical (EC) reduction of CO2:
EC reduction is the simplest one that can work on a huge scale. The electrocatalyst assists in transferring electrons.
Electrochemical carbon dioxide reduction is the manipulation of catalysts consisting of single metals to improve selectivity for a desired product, without changing the bonding environment of metal nanoparticles.
This has lead to the development of electrocatalysts for selectively reducing carbon dioxide.
In this image, electrochemical reduction of carbon dioxide to methanol has been done using a perovskite oxide cathode ( A cathode is the electrode from which a current leaves an electrical device). By powering this process using renewable sources of electricity, it is possible to generate carbon-neutral fuels:
Perovskite oxides are appealing as tunable catalysts because the cationic composition can be systematically varied without altering the crystal structure, which allows for more precise tuning of binding energies.
For CO2 EC reduction, a variety of electrocatalysts including metals, metals oxides, metallic nanostructures and molecular complexes can be used.
I’ll be summarizing some metallic nanostructures which have worked the best.
The products obtained after the CO2 EC reduction depends upon various factors like the kind of materials, electrolyte and also on voltage, temperature and pressure.
To improve CO2 EC reduction efficiency, the nanostructured metallic materials work really well because of their versatile properties:
- high surface area
- contain a large portion of edge or low coordinated sites
- They show different catalytic behavior as compared to the bulk materials.
There are various different Metallic Nanostructures, for example:
Silver (Ag) Nanostructure
Ag nanostructure co-catalyzed by ionic liquid (an ionic liquid is a salt in the liquid state) have ability to reduce CO2 into CO.
For Ag nanoparticles (Ag NPs) electrodes, size has a huge influence on the catalytic activity of Ag NPs. By decreasing size, there is an increase in activity but this happens to some extent at particular size of about less than 5 nm.
As compared to bulk Ag, the rate of reduction is 10 times higher than 5 nm Ag NPs. The smaller particles have more binding energies compared to bulk materials because the intermediates formed have more stability for further reduction. But when particle size become too small, the intermediate bind becomes more strongly to surface, making the product release more difficult.
So for ideal scenarios, the electrocatalyst should have appropriate intermediate binding strength, not very strong or very weak.
Gold (Au) Nanostructure
Nanostructured Au catalysts have been focused on, which show increased catalytic activity and higher conversion efficiency as compared to polycrystalline or single crystalline surface.
Star of the show: Copper (Cu) Nanostructure
Copper (Cu) is one of most studied metal electrocatalysts for CO2 reduction because of its unique properties. It has the ability to reduce CO2 into a variety of hydrocarbon products that can be used as fuels.
In order to improve the catalytic activity of Cu electrode, different kinds of Cu nanostructured have been fabricated including nanoparticles of zero-dimensional (0D) and one-dimensional (1D), two-dimensional (2D) overlayers and three-dimensional (3D) foams.
Other really COOL applications
of how nanotechnology can help to combat and possibly stop climate change:
- Lightweight nano-composite materials: To reduce emissions in vehicles we need to reduce their weight which in turn decreases the fuel consumption. A 10% reduction in weight of the vehicle corresponds to a 10% reduction in fuel consumption.
We can use novel materials in Nanotechnology which are lightweight. For example, use of lighter, stronger, and stiffer nano-composite materials is considered to have the potential to significantly reduce vehicle weight.
2. Nano-coatings: Nanotechnology coatings are a good short-term way of reducing emissions and maximizing clean energy production. For example, nano-coatings can be applied to aircraft, which can make aircraft’s smoother, reducing drag and also protect the materials from the special conditions of the environment where they are used.
Since the amount of CO2 emitted by an aircraft engine is directly related to the amount of fuel burned, CO2 can be reduced by making the airplane lighter. Hydrophobic nano-coatings can also improve the energy produced from solar panels for example.
3. Nano-structured Materials: Residential and commercial buildings contribute to 11% of total greenhouse gas emissions. Space heating and cooling of residential buildings account for 40% of the total residential energy use. Nanostructured materials, such as aerogels, have the potential to greatly reduce heat transfer through building elements and assist in reducing heating loads placed on air-conditioning/heating systems.
The world of Nanotechnology is a crazy cool one. This is just some of the potential that it holds for energy & solving our climate crisis. As these materials and processes also become cheaper, they will become more scalable in bulk.
I don’t know about you but a world climate change free is the one I want to live in, so we better get to work.
Hi. I’m Alishba.
I’m so excited to be working in the space of clean energy + sustainability using Nanotechnology, for the next few months. I’d love to connect with you and chat more about the tech + research I’m doing. Feel free to reach out!