{"id":906,"date":"2016-12-20T14:01:40","date_gmt":"2016-12-20T19:01:40","guid":{"rendered":"https:\/\/techfragments.com\/?p=906"},"modified":"2022-09-19T17:35:11","modified_gmt":"2022-09-19T21:35:11","slug":"graphene-dots-recycle-co2","status":"publish","type":"post","link":"https:\/\/techfragments.com\/graphene-dots-recycle-co2\/","title":{"rendered":"Graphene Quantum Dots Recycle Waste CO2 Into Fuel"},"content":{"rendered":"

Nitrogen-doped graphene quantum dots<\/a> could represent a simple method for recycling waste carbon dioxide into valuable fuel, rather than releasing it into the atmosphere or burying it underground, say Rice University scientists.<\/p>\n

Nitrogen-doped graphene quantum dots (NGQDs) are an efficient electrocatalyst to make complex hydrocarbons from carbon dioxide, according to the research team. Using electrocatalysis, Rice University materials scientist Pulickel Ajayan<\/a>‘s lab has shown the conversion of this greenhouse gas into small batches of ethylene and ethanol.<\/p>\n

Though they don\u2019t entirely understand the mechanism, the researchers found NGQDs worked nearly as efficiently as copper, which is also being tested<\/a> as a catalyst to reduce carbon dioxide into liquid fuels and chemicals. And NGQDs keep their catalytic activity for a long time, they report.<\/p>\n

\u201cIt is surprising because people have tried all different kinds of catalysts. And there are only a few real choices such as copper. I think what we found is fundamentally interesting, because it provides an efficient pathway to screen new types of catalysts to convert carbon dioxide<\/a> to higher-value products,\u201d<\/p><\/blockquote>\n

Ajayan says.<\/p>\n

Curb Your Carbon Dioxide<\/h2>\n

Atmospheric carbon dioxide rose above 400 parts per million earlier this year, the highest it\u2019s been in at least 800,000 years, as measured through ice-core analysis.<\/p>\n

\u201cIf we can convert a sizable fraction of the carbon dioxide<\/a> that is emitted, we could curb the rising levels of atmospheric carbon dioxide levels, which have been linked to climate change,\u201d<\/p><\/blockquote>\n

said coauthor Paul Kenis of the University of Illinois.<\/p>\n

In lab tests, nitrogen-doped graphene quantum dots proved able to reduce carbon dioxide by up to 90 percent and convert 45 percent into either ethylene or alcohol, comparable to copper electrocatalysts.<\/p>\n

Quantum Dots<\/h2>\n
\"Nitrogen-doped

Nitrogen-doped graphene quantum dots stand out from a substrate in a transmission electron microscope image. Credit: Ajayan Group\/Rice University<\/p><\/div>\n

Graphene quantum dots are atom-thick sheets of carbon atoms that have been split into particles about a nanometer thick and just a few nanometers wide.<\/p>\n

The addition of nitrogen atoms to the dots enables varying chemical reactions when an electric current is applied and a feedstock like carbon dioxide is introduced.<\/p>\n

\u201cCarbon is typically not a catalyst,\u201d Ajayan says. \u201cOne of our questions is why this doping is so effective. When nitrogen is inserted into the hexagonal graphitic lattice, there are multiple positions it can take.<\/p>\n

Each of these positions, depending on where nitrogen sits, should have different catalytic activity. So it\u2019s been a puzzle, and though people have written a lot of papers in the last five to 10 years on doped and defective carbon being catalytic, the puzzle is not really solved.\u201d<\/p><\/blockquote>\n

Co-lead author Rice postdoctoral researcher Jingjie Wu, says:<\/p>\n

\u201cOur findings suggest that the pyridinic nitrogen (a basic organic compound) sitting at the edge of graphene quantum dots leads the catalytic conversion of carbon dioxide to hydrocarbons. The next task is further increasing nitrogen concentration to help increase the yield of hydrocarbons.\u201d<\/p><\/blockquote>\n

Ajayan notes that while electrocatalysis is effective at lab scales for now, industry relies on scalable thermal catalysis to produce fuels and chemicals.<\/p>\n

\u201cFor that reason, companies probably won\u2019t use it any time soon for large-scale production. But electrocatalysis can be easily done in the lab, and we showed it will be useful in the development of new catalysts.\u201d<\/p><\/blockquote>\n

Original Study:<\/strong> A metal-free electrocatalyst for carbon dioxide reduction to multi-carbon hydrocarbons and oxygenates<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Nitrogen-doped graphene quantum dots could represent a simple method for recycling waste carbon dioxide into valuable fuel, rather than releasing it into the atmosphere or burying it underground, say Rice University scientists. Nitrogen-doped graphene quantum dots (NGQDs) are an efficient electrocatalyst to make complex hydrocarbons from carbon dioxide, according to the research team. Using electrocatalysis,…<\/p>\n","protected":false},"author":2,"featured_media":910,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[73],"tags":[135,12,100],"_links":{"self":[{"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/posts\/906"}],"collection":[{"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/comments?post=906"}],"version-history":[{"count":3,"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/posts\/906\/revisions"}],"predecessor-version":[{"id":972,"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/posts\/906\/revisions\/972"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/media\/910"}],"wp:attachment":[{"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/media?parent=906"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/categories?post=906"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/techfragments.com\/wp-json\/wp\/v2\/tags?post=906"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}