Nov 11 2019
Researchers from Trinity College Dublin have taken a massive stride towards finding an answer to a puzzle that would offer the world a totally renewable, clean energy from which the sole waste product would be water.
Left to right, Professor Max Garcia-Melchor and PhD Candidate Michael Craig, Trinity College Dublin. Image Credit: Trinity College Dublin.
Decreasing human-induced carbon dioxide (CO2) emissions is debatably the paramount challenge facing the 21st-century civilization—particularly given the constantly growing global population and the intensified energy demands that accompany it.
One ray of hope is the concept that renewable electricity could be used to split water (H2O) to create energy-rich hydrogen (H2), which could be subsequently stored and used in fuel cells. This is a particularly stimulating perspective in a situation where solar and wind energy sources generate electricity to split water, as this would enable the storage of energy for use when those renewable sources are not available.
The vital issue, however, is that water is highly stable and necessitates a considerable amount of energy to split up. A specifically major obstacle to overcome is the energy or “overpotential” related to the formation of oxygen, which is the bottleneck reaction in splitting water to generate H2.
Although some elements like Iridium or Ruthenium (two of the noble metals of the periodic table) hold the potential to split water, these are exorbitantly expensive for commercialization. Other, inexpensive options tend to be less robust and/or have low efficiency. At the moment, no one has found catalysts that are robust, cost-effective, and highly active for substantial lengths of time.
So, how does one solve such a puzzle? Without any need for glasses, lab coats, beakers, and odd smells, this work was performed completely with a computer.
By uniting theoretical physicists and chemists, the Trinity team behind the latest innovation combined chemistry experts with highly robust computers to discover one of the “holy grails” of catalysis.
The team, headed by Professor Max García-Melchor, made a critical discovery while examining molecules that synthesize oxygen: Science had been undervaluing the activity of some of the more reactive catalysts. Consequently, the dreaded “overpotential” obstacle now seems easier to overcome.
By improving a long-accepted theoretical model used to estimate the efficiency of water splitting catalysts, they have made it extremely easier for people (or super-computers) to locate the mysterious “green bullet” catalyst.
Michael Craig from Trinity College Dublin, who was the lead author, is eager to implement this insight.
We know what we need to optimise now, so it is just a case of finding the right combinations.
Michael Craig, Study Lead Author, Trinity College Dublin
The team intends to use artificial intelligence (AI) to place a large number of earth-rich metals and ligands (which stick together to produce the catalysts) in a melting pot before evaluating which of the near-infinite combinations hold the greatest potential.
Together, what earlier appeared like an empty canvas currently appears more like paint-by-numbers as the researchers have defined fundamental principles for designing perfect catalysts.
Given the increasingly pressing need to find green energy solutions it is no surprise that scientists have, for some time, been hunting for a magical catalyst that would allow us to split water electrochemically in a cost-effective, reliable way.
Max García-Melchor, Study Senior Author and Ussher Assistant Professor in Chemistry, Trinity College Dublin
Professor García-Melchor continued, “However, it is no exaggeration to say that before now such a hunt was akin to looking for a needle in a haystack. We are not over the finishing line yet, but we have significantly reduced the size of the haystack and we are convinced that artificial intelligence will help us hoover up plenty of the remaining hay.”
This research is hugely exciting for a number of reasons and it would be incredible to play a role in making the world a more sustainable place. Additionally, this shows what can happen when researchers from different disciplines come together to apply their expertise to try to solve a problem that affects each and every one of us.
Max García-Melchor, Study Senior Author and Ussher Assistant Professor in Chemistry, Trinity College Dublin
Max García-Melchor, who is a Ussher Assistant Professor in Chemistry at Trinity, is the senior author on the breakthrough research that has recently been published in Nature Communications, a leading international journal.
Authors collaborating on this research include Gabriel Coulter, formerly of Trinity and now studying for an MSc at the University of Cambridge; Eoin Dolan, formerly of Trinity and currently completing an Erasmus Mundus joint MSc degree in Paris; Dr Joaquín Soriano-Lòpez, MSCA-Edge fellow in Trinity’s School of Chemistry; Eric Mates, PhD candidate in Trinity’s School of Chemistry; and Professor Wolfgang Schmitt from Trinity’s School of Chemistry.
The study has been supported by Science Foundation Ireland and the Irish Centre for High-End Computing (ICHEC), where the team is profiting from 4,500,000 CPU hours at Ireland’s high-tech super-computer facility.