The Catalysts That Feed, Heal, and Build our Society

Catalysts are the silent “workhorses” of chemistry. They make reactions faster, more efficient, and sometimes, they make them possible at all. At #LINO25, catalysis took center stage as Laureates explored how these molecular enablers already play a big role in our society, and how they could shape a more sustainable and healthier future.

A Catalytic Reaction Feeds the World

In a Lecture that mixed personal journey with sweeping insights, Nobel Laureate Sir David W.C. MacMillan returned to the roots of his transformative research. As MacMillan puts it, catalysis is “the reason we can feed eight billion people.”

The key reaction he is referring to is the Haber-Bosch process, a reaction for which both Fritz Haber and Carl Bosch have been awarded a Nobel Prize. In this process, nitrogen from the air is combined with hydrogen; the process takes place under high pressure and temperature and is catalyzed by an iron-based material. This process has been immensely impactful in our society, MacMillan emphasizes. It’s the foundation of our nitrogen-based fertilizers, and these fertilizers in turn enable our society to increase food production.

Simply put, without this reaction, we would not be able to feed the world. In fact, the impact of this reaction is so great that “50% of nitrogen atoms in your body come from synthetic ammonia,” MacMillan’s says, adding that this is his favorite bit of trivia. “If that doesn’t freak you out, nothing will.”

Yet this is just one example of how catalysis has quietly shaped the modern world. Catalysis doesn’t just make food production possible, it underpins nearly all of industrial chemistry. Ninety percent of industrial-scale chemical reactions use catalysis, MacMillan explained, and “35% of global GDP depends on it.” That number will only grow as the world transitions toward more sustainable and efficient chemical processes.

Yet catalysis itself has undergone quite a revolution.

The “Birth” of Organocatalysis

MacMillan recalled a turning point in his career. “I’m gonna take you back to 1998,” the Laureate said. At the time, catalysis was largely split into two main branches: biocatalysis (championed by another Nobel Laureate in the audience, Frances Arnold), and metal catalysis, the domain MacMillan himself was trained in.

Metal catalysts, the Laureate explained, typically consist of two parts. First, you have a metal center that performs the chemistry. Then, you have an organic ligand framework that holds it in place. These two parts raise different questions: some metals can be expensive or difficult to work with; meanwhile, the organic part is typically safe, abundant, and recyclable. So MacMillan asked himself: what if we only used the organic part of the catalyst instead of the metal? The idea laid the foundation for what would soon become organocatalysis.

Organocatalysis is a form of catalysis that utilizes metal-free organic molecules as catalysts. This approach has now become a third major branch, with MacMillan becoming a seminal figure in establishing this field. Along with Benjamin List, he was awarded the 2021 Nobel Prize in Chemistry “for the development of asymmetric organocatalysis”. MacMillan also coined the term “organocatalysis” before going on to design small, chiral organic molecules which are particularly important for drug discovery. MacMillan’s organocatalysts provide a greener, more efficient, and often less expensive method to synthesize specific chiral molecules with high selectivity. This overcome some of the limitations of traditional metal-based catalysts.

Organocatalysis immediately found applications. The first field was in flavors and fragrances, a major (and often overlooked) chemical industry. MacMillan described a collaboration to produce lily of the valley aroma compounds. Traditionally, this scent required six synthetic steps. With organocatalysis, it could be made in just one, and starting from renewable biomass. “It’s a great example of how sustainable chemistry can also be efficient chemistry,” he said.

But the field didn’t stop evolving. In what the Laureate describes as a “completely unexpected direction,” his team turned to light.

MacMillan’s research evolved to incorporate photoredox catalysis, a method that uses visible light to trigger reactions. While sunlight is free and abundant, organic molecules typically don’t absorb visible light. “But photoredox catalysts do,” he said. They take one blue photon and become the equivalent of 30,000 degrees Celsius while everything else stays at room temperature. The resulting energy allows chemists to activate stable organic compounds and generate radicals, molecules that can form entirely new chemical bonds.

MacMillan ingeniously merged the two fields to create an even more powerful new approach for chemical synthesis, sometimes referred to as “synergistic catalysis” or, more specifically, “photoredox organocatalysis.”

Scale It Up

These tools have moved rapidly from lab benches to industrial settings. MacMillan showed how several pharmaceutical giants are already working with photoredox catalysis for drug discovery and production, with examples ranging from HIV drugs to insulin analogues for diabetes treatment. Remarkably, these light-based reactions can even be done in DNA-encoded libraries in water, a setting traditionally incompatible with sensitive chemistry. These methods are also already used at the ton scale, a sign that the technology is already maturing.

Yet, even with all these new developments, metal catalysis still has a big role to play. Richard Schrock opened his Agora talk by comparing catalyst design to “cutting a master key that fits countless locks.” Schrock was awarded the Nobel Prize in 2005 for the development of the metathesis method in organic synthesis.

Schrock traced the story back to the 1970s, when he and others proposed the now-famous “metallacyclobutane” intermediate. By isolating tungsten and molybdenum compounds, he and his group laid the groundwork for catalysts robust enough for the factory floor. It’s those breakthroughs that would ultimately lead to the Nobel Prize with Yves Chauvin and Robert Grubbs.

The olefin metathesis reaction (first discovered over sixty years ago) is driven by special metal compounds called alkylidenes, which contain molybdenum or tungsten in a high oxidation state. Olefin metathesis is considered one of the most complex catalytic reactions outside of biology, and as Schrock mentions, it’s also one of the most “beautiful.”

The applications are also quite broad. Olefin metathesis is a cornerstone of modern synthesis as it creates carbon-carbon bonds in a wide range of molecules. It’s used in everything from pharmaceuticals to sports gear.

Schrock hasn’t stopped after his Nobel Prize, he’s continued pushing innovation and practical developments. He and his collaborators recently broke ground at a new plant in Budapest, where they aim to scale up olefin metathesis reactions using catalysts derived from his research. Ultimately, the goal is to create catalysts in large enough quantities that they can be used in industrial settings.

As the lectures in Lindau made clear, catalysis is no longer just a behind-the-scenes tool — it’s a driving force for innovation across chemistry, medicine, agriculture, and materials science.

The journey from fundamental discovery to real-world application is not only possible, it’s already underway.