It's not often that a breakthrough in sustainable chemistry is influenced by a fan letter.
But that's exactly what happened to the Yale chemist Hailiang Wang, whose laboratory makes small molecule and nanomaterial catalysts that remove unwanted material like carbon dioxide in the atmosphere from the environment and turn it into something useful.
In 2019 the journal Nature published a study from Wang's laboratory with a new carbon dioxide conversion catalyst. A few weeks later, Wang received an email from Robert Tuttle, a Yale alumnus who had read about Wang's research that winter in Naples, Florida.
"Here we are very concerned about the runoff of water from Lake Okeechobee and its impact on marine life from dangerous algal blooms and red tides, ”Tuttle wrote. “As you may know, such a runoff contains high levels of nitrates and phosphates from agriculture … During heavy rains, the Army Corps of Engineers had to drain water east or west into rivers that flow towards the Gulf of Mexico or the Atlantic. In recent years, this has resulted in huge deaths from marine life, toxic effects on human respiration, and loss of tourism revenue. "
At the end of his note, Tuttle made a suggestion:
"I wonder if your group, or others researching new materials and chemicals, are aware of such issues and may consider them worthy of study, ”he wrote. "With new techniques for catalysts like the ones you developed for carbon capture, I was wondering if others could be developed for the above (mentioned) environmental problems."
Now, more than a year later, Wang can answer yes.
In a new study published in the journal Nature SustainabilityWang and colleagues at Yale and the Southern University of Science and Technology in China described a new reaction that focuses on wastewater.
The catalytic reaction converts carbon dioxide and nitrate in the wastewater into methylamine. Methylamine is a highly valued chemical that is used in the synthesis of many pharmaceutical and agrochemical products. It is currently produced by the industry using fossil fuels with high temperature and high pressure chemical reactions.
The new reaction consists of at least eight individual steps that are completed in one reaction process – including the reduction of carbon dioxide, the reduction of nitrate, the carbon-nitrogen coupling and the further reduction of the coupled intermediate. This unique cascade process is catalyzed by cobalt phthalocyanine derivative molecules carried on the surface of carbon nanotubes. This type of catalyst was jointly developed by Wang's team at Yale and Yongye Liang's group at the Southern University of Science and Technology.
"The reaction we developed could enable the sustainable synthesis of methylamine from essentially environmental waste using renewable electricity at room temperature and atmospheric pressure, "said Wang, associate professor of chemistry in the Faculty of Arts and Sciences and a faculty member of the Energy Science Institute on the Yale West Campus.
The study's first author is Yueshen Wu, a former Yale graduate student who is now at the California Institute of Technology. Yongye Liang from Southern University is a co-author with Wang. Zhan Jiang and Zhichao Lin, also from Southern University, are co-authors.
Wang credits his correspondence with Tuttle as part of the inspiration for completing his latest work.
"This research was driven by our continued interest in using our expertise in catalysis and electrochemistry to develop solutions to environmental problems, ”said Wang. "It was also motivated in part by my email conversation with a Yale alumnus."
Source: Yale University