Warwick chemists isolate elusive compounds of greenhouse gas

A key technique that is being considered in our endeavour to tackle climate change is carbon capture. There are already a lot of greenhouse gases in the environment to add to the enhanced greenhouse effect. Therefore these gases need to be removed from the environment, as well as significantly reducing further emissions, to reduce the rate at which the global temperatures are rising.

However, carbon dioxide is not the only greenhouse gas. There are other gases, some of which are even more potent than carbon dioxide, that add to the effect. These include methane, water vapour, and nitrous oxide. Nitrous oxide, or N₂O, is not only a greenhouse gas but also the dominant ozone-depleting substance emitted in the 21st century. This makes it a very powerful atmospheric pollutant. Although N₂O is naturally occurring, human activities have led to greater amounts of it being released into the environment through processes such as intensive agricultural fertilisation, industrial processes, and combustion of fossil fuels and biomass.

However, carbon dioxide is not the only greenhouse gas. There are other, and sometimes more potent gases, that add to the effect

Finding a favourable utility for nitrous oxide in the chemical process would be a major step forward in tackling climate change and addressing the issue of ozone depletion. Indeed, researchers in the chemistry department at the University of Warwick have identified transition metal compounds of nitrous oxide that provide a hint as to how the gas could be used in sustainable chemical technologies. This would be in the field of chemical catalysis where N₂O could enable energy-intensive chemical reactions to occur in milder conditions. Specifically, nitrous oxide can be used as an oxidant in the discipline of organic chemistry. This research provides the most comprehensive experimental data on the activity of nitrous oxides coupled with rhodium, which is of great significance because rhodium is one of the most widely employed transition metals in organic chemistry.

Nitrous oxides are 300 times stronger than carbon dioxide in terms of their performance in contributing to the greenhouse effect, all while having a half-life of 114 years. Dr Adrian Chaplin at the University of Warwick commented that: “Nitrous oxide is commonly known as laughing gas, but its environmental impact is certainly nothing to laugh about.” It is for this reason that the group has employed a ‘bottom-up’ approach to utilise the gas to do sustainable chemistry which would help to lower its emissions into the atmosphere.

Dr Adrian Chaplin at the University of Warwick commented that: “Nitrous oxide is commonly known as laughing gas, but its environmental impact is certainly nothing to laugh about”

Until now, the ambitious attempts of researchers to develop alternative methods of chemical synthesis which are less energy-intensive and more environmentally friendly provided little hope. However, the work from Chaplin’s lab is likely to offer a starting point as research in catalyst development continues. The research has been published in Angewandte Chemie  and Dr Chaplin remarked that: “The associated experimental data seems to be guiding us in the right direction and we are looking forward to where it takes us.” There is now a renewed sense of hope that nitrous oxide, a waste and pollutant gas, which is released through anthropogenic activities could serve as a chemical feedstock and help advance our efforts in switching the economy from a linear to a more circular model.