Stepping on the gas

This is the view of Prof Dermot O’Hare at Oxford University, who believes that a breakthrough in his technique to convert CO₂ into methanol could soon allow the gas to be used for greener applications such as renewable fuels.

‘CO₂ is a hard nut to crack because its bonds are very strong,’ he said. ‘Coupled with the fact that it’s a gas, anything you want to do with it becomes much more complicated… We’ve managed to solve some of these issues that could lead to the use of CO₂ that would otherwise be stored deep underground.’

O’Hare’s process is based on the use of Frustrated Lewis Pairs (FLPs) chemical mixtures that can split a hydrogen molecule without the use of metal catalysts. FLPs are highly reactive and bond with the hydrogen ions. The reaction leaves two molecules able to bond with CO₂.

The chemistry behind the conversion has been attempted by several researchers but, until now, no one has been able to exclusively produce methanol under such mild conditions from this technique.

“CO₂ is a hard nut to crack because its bonds are very strong”

‘Methanol is quite a nice fundamental building block for organic chemistry,’ said O’Hare. ‘At the moment, most of methanol is being produced from methane, which uses up fossil-fuel reserves. With our technique, we will be doing two useful things — making a feedstock and sequestering existing CO₂.’

To be feasible, the method will have to work with a process that generates hydrogen, needing extra power and a possible rise in CO₂. The challenge is something that O’Hare believes can be addressed in the near future. ‘The problem of where you get hydrogen from hasn’t been solved yet,’ he said. ‘But I think the ultimate solution is that hydrogen has to come from water and the energy to split hydrogen from oxygen and water will probably ultimately have to come from the sun and its radiation.’

The team, which includes Dr Andrew Ashley, is hoping to secure additional funding to develop a reactor that is able to continuously generate methanol and water. It will also be targeting petrochemical companies with its own source of hydrogen to help refine the process further.