South Korean researchers from Ulsan National Institute of Science and Technology (UNIST) have devised a new technique to fix nitrogen to graphene, from the July 24, 2013 news item on Azonano,
A simple, low-cost and eco-friendly method of creating nitrogen-doped graphene nanoplatelets (NGnPs), which could be used in dye-sensitized solar cells and fuel cells, is published in Scientific Reports today.
The work, carried out at Ulsan National Institute of Science and Technology (UNIST) in South Korea, could be a step towards replacing conventional platinum (Pt)-based catalysts for energy conversion.
The UNIST July 23, 2013 news release by Eunhee Song, which originated the news item, provides some context for why the technique is exciting interest,
The search for economically viable alternatives to fossil fuels has attracted attention among energy communities because of increasing energy prices and climate change. Solar cells and fuel cells are to be promising alternatives, but Pt-based (platinum-based) electrodes are expensive and susceptible to environmental damage.
Nitrogen fixation is where nitrogen (N2) in the atmosphere is converted into ammonia (NH3). Fixation processes free up nitrogen atoms from their diatomic form to be used in other ways, but nitrogen does not easily react with other chemicals to form new compounds.
The most common method of industrial nitrogen fixation is the Harber-Bosch process, which requires extremely harsh conditions, 200 atm of pressure and 400 °C of temperature.
The UNIST team previously reported that dry ball-milling can efficiently produce chemically modified graphene particles in large quantities*. This research, in Scientific Reports, presents another innovation to improve the materials. Along the way, the research team discovered a novel nitrogen fixation process.
They focus on modifications with nitrogen, developing a technique with direct nitrogen fixation, carbon-nitrogen bond formation, at the broken edges of graphite frameworks using ball-milling graphite in the presence of nitrogen gas.
In my search for this latest paper I found an earlier piece of work based on a wet-chemical reaction and published in the Journal of the American Chemical Society,
Nitrogen-Doped Graphene Nanoplatelets from Simple Solution Edge-Functionalization for n-Type Field-Effect Transistors by Dong Wook Chang, Eun Kwang Lee, Eun Yeob Park, Hojeong Yu, Hyun-Jung Choi, In-Yup Jeon, Gyung-Joo Sohn, Dongbin Shin, Noejung Park, Joon Hak Oh, Liming Dai, and Jong-Beom Baek. J. Am. Chem. Soc., 2013, 135 (24), pp 8981–8988 DOI: 10.1021/ja402555n Publication Date (Web): May 27, 2013
Copyright © 2013 American Chemical Society
That paper is behind a paywall while this latest work featuring a ‘dry’ technique is open access,
Direct nitrogen fixation at the edges of graphene nanoplatelets as efficient electrocatalysts for energy conversion by In-Yup Jeon, Hyun-Jung Choi, Myung Jong Ju, In Taek Choi, Kimin Lim, Jaejung Ko, Hwan Kyu Kim, Jae Cheon Kim, Jae-Joon Lee, Dongbin Shin, Sun-Min Jung, Jeong-Min Seo, Min-Jung Kim, Noejung Park, Liming Dai, & Jong-Beom Baek. Scientific Reports 3, Article number: 2260 doi:10.1038/srep02260 Published 23 July 2013
This team has been quite prolific recently. I last mentioned them in a June 7, 2013 posting highlighting another iteration of this ‘dry’ technique.