SydneySCIENCE Highlights

Sustaining our uncertain future: science to save the planet

A technical chemist specialising in catalysts – compounds and materials that speed up reactions – Professor Thomas Maschmeyer hopes to help address the world energy crisis with a solar powered process. He is harnessing sunlight to generate hydrogen by splitting wastewater.

Sydney Science - Sustainability

“Success in green chemistry is often a matter of designing integrated macrostructures that assist catalytic reactions. We make each component as compact as possible and try to efficiently bring all active sites together.”

“More solar energy reaches the earth in one hour than the world needs for a year,” explains Maschmeyer. Using cadmium sulphide and ionic liquids, Maschmeyer has revolutionised the synthesis of this type of photocatalyst to create a system that is highly active in the visible region and stable for long periods of time.

However until this process overcomes its industrial lead time and becomes an economic reality there is a need for immediate solutions, such as converting brown coal, a low ranking coal similar to peat, into a liquid fuel. Brown coal is by far the world’s worst fuel; any improvement in its production will have an immediate global impact.

Maschmeyer and team recognise the demand for brown coal and are realistic about its use. “Industry is going to use it so we had better make the process more efficient.” Maschmeyer splits brown coal into small pieces to produce oil and microionised char; this process of depolymerisation breaks the chain of molecules to release useful compounds.

“We can change wet solid brown coal into a dry liquid oil to run combustion processes via gas turbines and cogeneration. With widespread use this would reduce the greenhouse gas emissions of power stations by up to 50 per cent,” enthuses Maschmeyer.

An alternative is the conversion of biomass into fuels, such as biodiesel and lignocellulosic ethanol or directly into stable bio-oils.

“Biodiesels have a bad reputation. Some people claim that they compete with agriculture and contribute to increasing food price. While this might be the case in the long-term with extensive use of food crops for food, current use is simply too low to have a global impact other than that induced by market speculation” explains Maschmeyer.

Plant matter is comprised of an intricate lattice of crystalline and non-crystalline sugars wrapped inside a lignin coating, making separation extraordinarily difficult. Supercritical treatment applies extreme pressure to create an aggressive state of water, which is simultaneously acidic and basic and can dissolve oil. In a world first, Maschmeyer has exploited this process to generate stable bio-oil from biomass in one step. Bio-oil can make refinery products, and their derivatives, increasingly renewable without necessitating costly rebuilding of infrastructure.

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