From understanding catalysts to designing them

My research career began with a seemingly simple question: what is the real catalytic species responsible for a reaction?

During my PhD, I investigated the catalytic behaviour of small amounts of gold and other metals in organic reactions. This work revealed that very small metal aggregates could form in solution and act as the actual catalytic species. These results, published in journals including Science, Angewandte Chemie and Journal of the American Chemical Society, opened a new research direction at the Instituto de Tecnología Química.

This experience changed the way I think about catalysis. Rather than considering a catalyst as a static material with a fixed structure, I became interested in understanding how catalytic species form, how they evolve under reaction conditions and, most importantly, which structural features are responsible for their activity.

Looking at catalysts while they are actually working

To answer these questions, it is not enough to characterize a catalyst before or after a reaction. Catalysts can restructure, change their oxidation state, interact with reactants or form new active species while the reaction is taking place.

This motivated my research at Lawrence Berkeley National Laboratory, where I received advanced training in in situ techniques such as ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) and X-ray absorption spectroscopy (XAS) at synchrotron facilities. I applied these approaches to investigate bimetallic catalytic systems, including PdAg, and subsequently extended this work to CoAu and CoMn catalysts.

Synchrotron-based characterization became a particularly powerful tool in my research because it allows us to connect the atomic-scale structure of a catalyst with its behaviour under realistic conditions.

From single atoms and clusters to multimetallic nanoparticles

After returning to the ITQ, I applied this approach to increasingly complex catalytic systems, including single atoms and metal clusters confined within zeolites and metal-organic frameworks (MOFs). More recently, my research has expanded towards bi- and multimetallic nanoparticles.

Why combine different metals?

Because introducing a second or third element can fundamentally modify the electronic structure, surface properties and reactivity of a nanoparticle. The challenge is that these materials are often structurally complex: small changes in composition, particle size, oxidation state or metal distribution can lead to very different catalytic behaviour.

My aim is therefore not simply to prepare new nanoparticles, but to rationally design their surfaces and understand why they work. Projects supported through competitive funding have addressed multimetallic systems confined in porous materials and the characterization of their catalytic properties using synchrotron XAS and AP-XPS.

Designing catalysts for more sustainable chemistry

Understanding the catalyst is only one part of the problem. The next step is to translate this knowledge into chemical processes that use fewer resources and generate less waste.

My research therefore increasingly focuses on sustainable organic transformations, including reactions performed under flow conditions. Flow chemistry offers important advantages for sustainable synthesis, including improved control of reaction conditions and the possibility of integrating catalytic processes into continuous operation.

In parallel, I have investigated heterogeneous catalysts such as zeolites and supported metal nanoparticles for organic synthesis, as well as catalytic approaches to the functionalization of hydrocarbons and the development of sustainable processes from alternative feedstocks. Recent work has included sustainable organic synthesis in batch and flow procedures and the development of catalytic systems for selective organic transformations.

From fundamental science to real-world applications

An important aspect of my research is the connection between fundamental understanding and technological application. Over the years, my work has generated patents, licensed technologies and collaborations with industry, including projects related to sustainable organic processes, polymer functionalization and the development of catalysed processes for the synthesis of organic compounds.

This translational perspective is particularly relevant to my current research vision. The catalysts of the future will need to combine high activity, selectivity and stability with abundant or efficiently used elements, reduced waste and compatibility with intensified and continuous processes.

A new research direction

My current position as a Tenured Scientist at CSIC marks a new stage in this trajectory. My research line, “Rational design of supported nanoparticles for sustainable flow catalysis,” brings together the different elements that have shaped my career: nanoscale catalyst design, surface chemistry, synchrotron characterization, multimetallic materials and sustainable organic synthesis.

The long-term objective is to establish clear structure–property–reactivity relationships that allow catalytic materials to be designed rather than discovered by trial and error.

Ultimately, I would like to move from the question “What catalyst works?” to a more ambitious one:

“Can we predict what a catalyst should look like in order to make a chemical process more efficient and sustainable?”

That is the challenge that will guide my research in the coming years.