Accelerated design of metal-free catalysts for CO2 conversion using alchemical reaction networks

The past few summers - with wildfires raging across Europe, the US, and Canada, and the hottest average temperatures ever recorded around the globe - have shown us what our future looks like if we do not reduce atmospheric CO2 levels. According to the UN IPCC, we have, at best, a few decades before we reach ‘tipping points’ of irreversible and catastrophic climate change- without scientific efforts to develop new capture, recycling, and re-use technologies for CO2, the world that future generations will inherit will be significantly poorer, less stable, and less healthy, and our natural environments will be decimated. There is no question about the urgency of addressing CO2 mitigation. Chemical scientists are best placed to develop new chemical technologies to mop-up and re-use CO2 - but progress in such efforts have been fitful and unfocussed. For example, many different chemical systems have been experimentally-developed that are capable of transforming CO2 into other useful species, like recyclable polymers, fuels such as methanol, or hydrogen-storage vectors like formic acid - but adoption and wider awareness of these is too often hampered by reliance on expensive and/or toxic metals and cost-benefit properties that are not compatible with industrial economic realities. Furthermore, the reality of designing new chemistry to recycle CO2 too often relies on trial-and-error experiments and serendipity - an approach that is too slow and expensive to match the urgency required to address climate challenges. Here, we instead propose the first large-scale computational discovery study focussed exclusively on identifying promising new metal-free reactive systems that could transform our capability to re-use CO2 as part of cost-effective recycling systems. We will develop a computational approach that mimics, as closely as possible, the typical experimental design of new chemical reactions for CO2 recycling. Building on our expertise in automated reaction discovery, machine-learning, and chemical reaction kinetics, our new simulation approach will function as a “virtual reaction flask” that mirrors the experiments used to study different CO2 reactions in the lab. Our simulations will be used to design and optimize the performance of different molecular catalysts for CO2 utilisation - being completely “virtual", our strategy will be more cost-effective, faster, and less wasteful than traditional trial-and-error lab experiments. Importantly, our approach is based on extensive proof-of-concept demonstrating how we can already generate accurate models describing the emergent chemistry that might happen when one mixes together hundreds of different reactive molecules - the key goal of this new project is to couple this predictive power to computational approaches that enable design of new catalysts to recycle CO2. A primary output of this project will be a new computational tool (released to all as open-source software) for designing and optimising new catalysts to re-use CO2 - by demonstrating and disseminating our approach, we anticipate that this software will be taken up by both wider experimental and computational colleagues to accelerate the design of new catalysts to address global environmental challenges. Furthermore, this project will employ this new software to optimize new metal-free catalysts that can accelerate several important chemical reactions that utilise CO2 - by identifying new catalysts that are more reactive, selective, and stable than existing molecular catalysts, this research can help draw together researchers across the experimental/computational divide with the goal of developing future systems to address societal challenges such as CO2 recycling.