Next Big Thing: Catalysts can change the world

Next Big Thing: Catalysts can change the world

We now have more cars in Sydney’s CBD then we had in the 1970s, yet our air quality is radically better. Why? Because today we have catalytic converters installed in our vehicles to reduce emissions. In fact, about 90% of the world’s chemicals and organic materials are touched by catalysts during their production.

Catalysts can change the world. They already have. But there are big challenges ahead.

Fast facts: Catalysts

  • A catalyst speeds a chemical reaction up by offering an alternative way for chemicals to react.
  • They can also allow reactions to happen at lower temperatures, and direct the results of a reaction to favour certain products.
  • Catalysts can take many forms, from the complicated and highly specific enzymes in your body to organocatalysts, simple soluble organic molecules that are taking the world by storm.
  • Transition metals, are of particular interest as metal catalysts in chemistry and are foundational to the modern life.

Early on in my career, I became fascinated by the process of designing catalytic sites to influence the progress of chemical reactions. To be able to draw up a concept for a catalyst and then physically make it, to see it in action, to generate new molecules with it – this was just so exciting for me.

I also realised that if I want to help make our world more sustainable, I had to turn my attention to improving our chemical processes. Catalysis and catalysts are the obvious tools to do it.

For a start, I want to help create a future characterised by dramatic changes to the way we generate, distribute and use power. It’s generally agreed that our energy sources must be fully renewable. Less well understood is how this transition to renewable energy has the potential to also power what we call the “circular economy”, where clever re-purposing, re-using and recycling dramatically extends the lifetime of the raw materials we use.

I had to turn my attention to improving our chemical processes. Catalysis and catalysts are the obvious tools to do it.

Many years ago I was involved in the development of some of the views that are now commonly referred to as the “12 Principles of Green Chemistry” – for example, how we should think about processing using non-toxic materials, low energy inputs, low waste/no waste, high atom efficiency etc. These ideas join beautifully with our need to preserve the materials that we are using – plastics, for example.

“The circular economy needs to be powered. And this power has to come from renewable energy.”

The idea of a circular economy is simply a rational response to the fact that we are currently using just under two planets’ worth of resources to maintain the lifestyle of the one planet’s people. (If everybody lived the kind of lifestyle we enjoy in Australia, we actually would need around five planets!) We only have one – so the rational response is to use what we have over and over and over again. Hence, the term “circular economy”.

But the circular economy needs to be powered. And this power has to come from renewable energy. Such energy, like wind and solar, is often intermittent. Therefore, it needs buffers to interact with grid systems that have not been designed for this intermittent input.

Everyone agrees that batteries are the buffers that will be the backbone of our future energy grid. What used to be supplied by carbon-intensive fossil fuels will be supplied by reversible energy storage based on carbon neutral battery chemistries to ensure high-quality power for 24 hours a day. These power systems will give rise to largely untapped opportunities for wealth and job creation in a non-polluting power industry.

From my laboratory at the University of Sydney we spun out (2016) and successfully listed in London (2021) Gelion, a battery company with exciting technologies in zinc-based, and lithium-sulfur based, batteries.

Rubidium recting with water.
Credit: Digital Light Source / Getty Images

The zinc-based systems have their origin in using gels to control the flow of ions inside the battery. Highlighting the importance of basic science in generating impact breakthroughs, these gels were based on an effectively failed experiment exploring the fundamental science of gels, the insights of which were put to good use here.

We are excited about pursuing our aim to bring much higher power zinc-based batteries to applications traditionally dominated by lead acid technology, using similar production methods and lowering hurdles to production.

Our work on lithium sulfur batteries is targeted at delivering a sulfur platform cathode technology that can be paired to a range of lithium anode types, namely lithium/graphite, lithium/silicon (with and without carbon), and lithium metal. Such systems will yield batteries that are less than half the weight of the current best-in-class batteries for the same amount of energy stored. A revolution for the mobility sector, be it drones, cars, trucks or even short-range aeroplanes. Our recent acquisition of a broad IP portfolio from Johnson Matthey in the UK (82 patent families and 420 patents) perfectly complements Gelion’s proprietary IP in polysulfide management, making us a player with global relevance.

These power systems will give rise to largely untapped opportunities for wealth and job creation in a non-polluting power industry.

Plastic waste is another huge problem for the planet, but my company Licella’s catalytic hydrothermal reactor technology (Cat-HTR) can convert mixed end-of-life plastics that currently end up in landfill back into usable material. Our reactor system enables us to convert any organic polymer, be it biological or synthetic in origin, into gases, oils and waxes, as well as bitumen additives. For plastics, the efficiency of the process is such that 98.5% of all the carbon in the feedstock ends up in products leaving our reactor. We make about 15% gas, which is used to run the process. We also have been certified for sustainable Jet A fuel.

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The breakthrough moment came when we confirmed our understanding that the transfer of hydrogen from the aqueous process medium into the products generated would just about stop cross-linking of these products. Therefore, we had a suite of materials that did not need expensive hydrogen gas for their stabilisation. This transformed the economics of the process, leading to its global roll-out with partners/licensees including Dow, Shell, Mitsubishi Chemicals, LGChem, Chevron Phillips and Canfor.

Our next great challenge? We are working to generate ammonia from sunshine and air via electrolysis that can compete with the traditional Haber-Bosch process, which feeds the world by making fertiliser but creates approximately 3% of all CO2 emissions. Our initial reactor looks promising!

As told to Graem Sims for Cosmos Weekly.

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