{"id":23247,"date":"2018-01-11T15:13:07","date_gmt":"2018-01-11T20:13:07","guid":{"rendered":"https:\/\/college.unc.edu\/?p=23247"},"modified":"2024-07-02T16:53:48","modified_gmt":"2024-07-02T16:53:48","slug":"generating-power-like-plants","status":"publish","type":"post","link":"https:\/\/collegearchive.unc.edu\/?p=23247","title":{"rendered":"Generating Power Like Plants"},"content":{"rendered":"<p><em>When plants absorb sunlight, they\u00a0convert carbon dioxide\u00a0into energy-rich organic compounds. What if humans could do the same thing? What if we could pull CO2 out of the air and use it to build organic molecules? This revolutionary idea is still just that \u2014 an idea. But organic chemists at UNC are laying the groundwork for turning it into reality.<\/em><\/p>\n<figure id=\"attachment_23248\" aria-describedby=\"caption-attachment-23248\" style=\"width: 750px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-23248\" src=\"https:\/\/collegearchive.unc.edu\/wp-content\/uploads\/sites\/44\/2018\/01\/Foundations_chemistry_with-logo.jpg\" alt=\"A graduate student sets up a light-driven reaction with an organic dye. (photo by Mary Lide Parker)\" width=\"750\" height=\"500\" \/><figcaption id=\"caption-attachment-23248\" class=\"wp-caption-text\">A graduate student sets up a light-driven reaction with an organic dye. (photo by Mary Lide Parker)<\/figcaption><\/figure>\n<p>A freshwater aquarium looks a bit like an underwater garden \u2014 bright, green grasses grow next to burgundy leaves resembling arugula. Small, silver fish dart between the foliage, as streams of bubbles flow up through the water column.<\/p>\n<p>Dave Nicewicz stares at this array of life contained within the rectangular glass tank on his desk.<\/p>\n<p>\u201cLook at the little oxygen bubble at the edge of the leaf \u2014 that\u2019s a good one\u201d he says, pointing to the\u00a0plant with a reddish hue. A small heat lamp mimics the sun, radiating light into the tank, while six different species of plants release oxygen.<\/p>\n<p>\u201cI love this thing because you can actually <em>see<\/em> photosynthesis happening \u2014 you can\u2019t see that outside.\u201d<\/p>\n<figure id=\"attachment_23249\" aria-describedby=\"caption-attachment-23249\" style=\"width: 300px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-23249\" src=\"https:\/\/collegearchive.unc.edu\/wp-content\/uploads\/sites\/21\/2024\/07\/MG_4028_online.jpg\" alt=\"David Nicewicz points to the oxygen bubbles in his freshwater aquarium. (photo by Mary Lide Parker)\" width=\"300\" height=\"200\" \/><figcaption id=\"caption-attachment-23249\" class=\"wp-caption-text\">David Nicewicz points to the oxygen bubbles in his freshwater aquarium. (photo by Mary Lide Parker)<\/figcaption><\/figure>\n<p>As a research scientist, Nicewicz finds inspiration in photosynthesis. And while he loves plants (both his office and home are full of them) he is not a biologist \u2014 he\u2019s an organic chemist.<\/p>\n<p>\u201cI\u2019m not equating what we do to photosynthesis, but we\u2019re inspired by that process,\u201d he says.<\/p>\n<p>Nicewicz\u2019s ultimate goal is to use the most abundant source of energy on the planet \u2014 sunlight \u2014 to power chemical reactions. \u201cTo harvest sunlight in a way that either directly or indirectly can be used in chemical reactions by translating photons into electrons,\u201d he says. \u201cThat\u2019s the future.\u201d<\/p>\n<p>Humans have not yet engineered a way to create the complex biological machinery of plant life in a lab, according to Nicewicz, but the inspiration for the starting point is there \u2014 in the form of photo-redox catalysis.<\/p>\n<p>\u201cIt\u2019s just a fancy way of saying we use light to make cool molecules,\u201d says Nate Romero, a former PhD student of the Nicewicz lab.<\/p>\n<p>To explain this chemical process, it\u2019s helpful to break down each word. We\u2019re talking about creating reactions, and all reactions require an energy input \u2013 like heat or light. Photo refers to light, and redox refers to the transfer of electrons. Catalysis simply means using a catalyst, which decreases the amount of energy needed for a reaction to occur.<\/p>\n<p>\u201cWe can use a single catalyst to make hundreds or thousands or millions of molecules that we\u2019re interested in studying,\u201d says Cole Cruz, a graduate research assistant in the lab.<\/p>\n<p>By trying out different catalysts, this group of organic chemists can trim off one part of a molecule, or combine molecules that wouldn\u2019t typically combine. \u00a0These \u201ccool molecules\u201d play a major role in the development of vital plastics and medicines around the world \u2014 making the production process more economical and more environmentally friendly.<\/p>\n<p>To do that, Nicewicz and his students want to avoid the use of toxic metals, and utilize processes that generate little or not waste at all \u2014 the same way plants generate energy. \u201cThat\u2019s the challenge for chemical synthesis in the 21<sup>st<\/sup> century,\u201d he says. \u201cWe have to mimic how plants make molecules.\u201d<\/p>\n<p><strong>Light it up \u00a0<\/strong><\/p>\n<p>While scientists have been studying photo-chemistry over a century, photo-redox catalysis hasn\u2019t received mainstream attention until the past decade or so. Advances in technology, especially the widespread use of LEDs, and the ability to pinpoint precise wavelengths of light, have made it more commonplace, according to Nicewicz.<\/p>\n<p>More accessible and less expensive than lasers, LEDs are highly useful for organic chemistry because a researcher can utilize a particular color of light in a reaction.<\/p>\n<p>Researchers in the Nicewicz lab need highly energetic yet tiny wavelengths of light to power their reactions. They measure those wavelengths in nanometers \u2014 or one-billionth of a meter. A sheet of paper is about 100,000 nanometers thick. A strand of human DNA is 2.5 nanometers in diameter.<\/p>\n<p>\u201cThe output of these things is really narrow,\u201d Nicewicz says. \u201cTypically, a wavelength of 20 nanometers gives you pretty precise control.\u201d<\/p>\n<p>That precision is key for pinpointing the strongest reactions. Suppose a researcher has four components in a solution \u2014 if she uses thermal energy, then all four parts will be heated, which can lead to unwanted side reactions and wasted energy. By using light, the researcher has much more control.<\/p>\n<p>\u201cPerhaps one of them absorbs light at a specific wavelength that is different from all the others,\u201d Nicewicz says. \u201cYou can input energy into that one particular component in the presence of all the others, which means a selective reaction can take place \u2014 that\u2019s what we\u2019re getting at.\u201d<\/p>\n<p>They\u2019re not using plants in these reactions though. The lab uses a synthetic version of the pigments founds in plants \u2014 in the form of an organic dye. \u201cThere are some parallels to the dyes found naturally in plants, like chlorophyll, but ours are much more simplified,\u201d Nicewicz says.<\/p>\n<p>When an organic molecule inside that dye absorbs light, the molecule moves into a higher energy state, transporting electrons around, and creating a more powerful reaction to fuel production. The key for researchers in the Nicewicz lab is finding the perfect combination of color and light.<\/p>\n<figure id=\"attachment_23250\" aria-describedby=\"caption-attachment-23250\" style=\"width: 300px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-23250 size-medium\" src=\"https:\/\/collegearchive.unc.edu\/wp-content\/uploads\/sites\/21\/2024\/07\/MG_4067_online.jpg\" alt=\"Dye that students have created in the lab.\" width=\"300\" height=\"200\" \/><figcaption id=\"caption-attachment-23250\" class=\"wp-caption-text\">Dye that students have created in the lab.<\/figcaption><\/figure>\n<p><strong>Concoct a color<\/strong><\/p>\n<p>Organic dyes have been around for thousands of years. \u201cPurple dye is probably one of the most prized possessions of the ancient world \u2014 that was actually an accidental discovery,\u201d Nicewicz says.<\/p>\n<p>But the organic dyes that his lab produces are no accident. While dyes can come in many different colors, the Nicewicz lab mainly targets yellow and orange because they can absorb the highest energy light, and then put that energy to work in reactions. The dyes are easy to make using readily abundant, organic raw materials. Researchers combine extracts from essential oils \u2014 almond extract for example \u2014 with sulfuric acid in a dehydration reaction to create the powdery dye.<\/p>\n<div class=\"entry-content\">\n<p>Nicewicz is designing a new undergraduate lab section for second-year organic chemistry students to produce libraries of these dyes. He piloted the program during the 2017 summer session, then introduced a larger-scale version during the fall semester.<\/p>\n<p>\u201cWe have 200 undergraduates making these dyes,\u201d Nicewicz says. \u201cIt\u2019s easy chemistry, and they\u2019re using household items.\u201d<\/p>\n<p>The process involves designing simple reactions that students can complete in a single step. They pick different points to vary within the structure of the dye, and in the process, invent many slightly different dyes. \u201cThen we can evaluate those to see which combinations produce better reactivity,\u201d Nicewicz says. \u201cIn the first round of these we\u2019re hoping to generate about 500 structures per laboratory.\u201d<\/p>\n<p><strong>Turn it on\u00a0 \u00a0<\/strong><\/p>\n<p>The goal is to produce thousands of structures, and eventually find one that is <em>really<\/em> good. \u201cThis in an iterative process,\u201d Nicewicz says. \u201cWe find the winners from one set, take what we think are the most valuable properties of those, and then explore those properties farther in the next set so that we\u2019re constantly refining \u2014 it\u2019s like an algorithm.\u201d<\/p>\n<p>Another one of Nicewicz\u2019s long-term goals is to produce all these catalysts in a reusable fashion, utilizing a flow set up with the catalyst coating the walls of a reactor. \u201cWe flow our reactants through that, the reaction happens, and then we can recycle this catalyst indefinitely,\u201d he says.<\/p>\n<p>\u201cWe\u2019re constantly looking for new reactions, and for ways to improve on old ones,\u201d Romero says. \u201cUltimately, we hope these tools we\u2019ve developed from photo-redox catalysis can be useful for other chemists.\u201d<\/p>\n<p>And indeed, they have.<\/p>\n<p><strong>Support the industry <\/strong><\/p>\n<p>While much of their work focuses on creating new molecules, the Nicewicz lab also produces aromatic compounds. (For those outside the chemistry world, aromatic refers not just to smell but to a set of compounds with a distinctive stable structure.) The best known aromatic compound, which has a sweet, gasoline-like odor, is benzene. \u201cMost pharmaceuticals and agro-chemicals have a benzene embedded in them somewhere,\u201d Nicewicz says.<\/p>\n<p>Researchers start with the benzene core structure, and build off of that to make more complex structures. These compounds can be used to make anilines, which are used to create polyurethane coatings and medicines like Tylenol.<\/p>\n<p>Pharmaceutical companies often call this research \u201cdiscovery\u201d or \u201cmedicinal\u201d chemistry to find new compounds. \u201cThey want reactions they can do really easily to make thousands of molecules and then they screen those thousands of molecules against certain disease types,\u201d Nicewicz says. A process similar to that of Nicewicz\u2019s students begins \u2014 build up a library of compounds, find the winners, and then keep modifying them until you find the best possible one.<\/p>\n<p>\u201cThey\u2019re already using some of our science because it gets them to molecular structures in a much more concise manner than they have been previously,\u201d Nicewicz says. \u201cIn some cases, they make molecules that they can\u2019t make in any other way.\u201d<\/p>\n<p>Pharmaceutical companies like Merck, BMS, Novartis, and AbbVie use chemistry developed in the Nicewicz lab. But Nicewicz and his students continue to address problems like how to flow the chemicals past the light to get the desired reaction. \u201cThese problems will be solved in the long run,\u201d Nicewicz says. \u201cThey just require a little bit of hard work.\u201d<\/p>\n<p><strong>Build for the future <\/strong><\/p>\n<p>While photosynthesis began roughly 3 billion years ago, the planet was not covered in forests until 500 million years ago. Nicewicz hopes humans can refine a synthetic version of photosynthesis a bit faster than that.<\/p>\n<p>\u201cThere is so much that goes into being able to synthesize molecules in ways that are as complex as what plants do,\u201d Nicewicz says. The work of his lab and others in the field of organic chemistry is just one part of it \u2014 we also need advances in physics, engineering, and biology.<\/p>\n<p>And it\u2019s not just a matter of using sunlight. Nicewicz wants to utilize other naturally occurring energy feedstocks.<\/p>\n<p>\u201cWe can burn petroleum, or we can use it to make valuable medicines and materials\u2014I think that\u2019s what we should be doing to take better advantage of this valuable resource,\u201d Nicewicz says. \u201cInstead we\u2019re just burning it and causing more problems. What my lab is trying to do is take those abundant resources and turn those into chemicals that we need on an everyday basis.\u201d<\/p>\n<p>Back in his office, Nicewicz envisions a future where this process could exist, and the impact it would have.<\/p>\n<p>\u201cIt would mean that we don\u2019t have to extract oil from the ground. It would mean that we don\u2019t even have to process biomass, which is energy-intensive,\u201d he says. \u201cIf we could just pull CO2 out of the air and selectively insert those carbon atoms where we want in a molecule, that would mean we\u2019re just as good as plants \u2014 but we\u2019re not yet.\u201d<\/p>\n<p>Nicewicz turns back to the aquarium, and smiles at the percolating oxygen bubbles. \u201cIt\u2019s pretty incredible that plants can do that.\u201d<\/p>\n<\/div>\n<div class=\"boilerplate\">\n<p><em>Dave Nicewicz is an associate professor and director of graduate studies in the Chemistry department.<\/em><\/p>\n<p><em>Cole Cruz is a graduate research assistant in the Nicewicz lab.<\/em><\/p>\n<p><em>Nate Romero is a postdoctoral fellow in the Swager Group at MIT.<\/em><\/p>\n<p><a href=\"https:\/\/endeavors.unc.edu\/generating-power-like-plants\/\"><em>By Mary Lide Parker, Endeavors magazine<\/em><\/a><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>When plants absorb sunlight, they convert carbon dioxide into energy-rich organic compounds. What if humans could do the same thing? What if we could pull CO2 out of the air and use it to build organic molecules? This revolutionary idea is still just that \u2014 an idea. But organic chemists at UNC are laying the groundwork for turning it into reality.<\/p>\n","protected":false},"author":4,"featured_media":23248,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center 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