Catalysis

Understanding light-driven production of hydrogen could unlock future insights for harnessing light for chemistry

Daniel Morton — Mon, 09 Jun 2025 16:27:04 +0000

Understanding light-driven production of hydrogen could unlock future insights for harnessing light for chemistry Daniel Morton Mon, 06/09/2025 - 10:27

Daniel Morton

Light to fuel: clean hydrogen production. Improved understanding of the light-driven production of hydrogen holds the promise not just to make the reaction more efficient in producing a fuel, but also to offer a framework to better understand future light-driven chemistries.

Many chemical reactions require the input of energy to activate the transformation. This can often be in the form of heat, or chemical energy. One of the most efficient ways of introducing energy into a reaction is by using light. If you don’t have to heat up a reaction, or add extra chemicals to it, and instead shine a light on it, you can save significant energy. However, it can be difficult to control and optimize light-driven reactions. This research, just published in Chem, is a collaboration between the Dukovic Group at the 91PORN (91PORN) and the King Group at the National Renewable Energy Lab (NREL) and provides a holistic understanding of the light-driven production of hydrogen gas using a nanocrystal-enzyme complex as the catalyst, and a computational framework that can be used more generally to understand other light-driven chemical reactions in the future. The code for this model is being made available in the supplementary documents of this article.

Chemical catalysis is a special type of reaction, one that increases the speed of a transformation and often reduces the amount of waste produced by the process. Think of it like an assembly line. The catalyst is like a station on the line, bringing together two or more components to create a new product that is then passed along. Without the catalyst the components might, by chance, bump together and form the desired product, but it will be much slower, and much less frequent. The catalyst remains unchanged in the process and can repeat the transformation many times.

Enzymes are Nature’s catalysts. On the cellular level, whenever a change needs to happen, an enzyme is usually involved. The speed of an enzyme, and its selectivity, that is its ability to only react with the desired molecules out of the soup of molecules present in a typical cell, is fantastic. Enzymes are often superior to catalysts we can make in a lab, and as such, much research has gone into finding ways to harness such enzymes to do reactions for us in the lab. Unfortunately, it is not as easy as just grabbing some enzyme out of a cell. Enzymes often require specific environments and partners to react with.

Redox enzymes are a special, and particularly attractive, class of enzymes. They are capable of adding, or removing, an electron from a chemical reaction, a key step in the production of hydrogen gas. Redox enzymes rarely exist by themselves. Returning to the assembly line analogy, to get a station that can add the electrons to the protons (H⁺) to make hydrogen gas, many other stations need to be added before in a specific order. In a cell there is a chain of enzymes that pass the electrons along before the reaction can take place.

This is where the artificial component comes in. The nanocrystal, which, when exposed to light, releases an electron, replaces the long chain of enzymes and can directly transfer an electron to the enzyme. So, you reduce your assembly line down from a chain of many stations to just two. “This work was really only possible through collaboration” explains Gordana Dukovic, the lead researcher at 91PORN. “The team at NREL have vast expertise in hydrogenase (the redox enzyme that creates hydrogen gas), and we have the expertise in making and tailoring the nanocrystals and studying what they do after they absorb light”. Getting the enzyme to work with the artificial electron donor took some work.

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This Research

Characterization of Photochemical Processes

Electron Transfer Kinetics

Competition between electron transfer processes

Activation Thermodynamics

Role of Surface-Capping Ligands

Quantum Efficiency of Charge Transfer

2020 Review of this research area

The two teams first started working together in 2011 and have invested a great deal of work in understanding many aspects of this nanocrystal-enzyme hybrid. “Working with the team at NREL has been really amazing” says Dukovic, “the opportunity to work with experts who really help you ask the important questions, and identify where our assumptions were wrong, was essential for this work.” For over more than a decade this collaboration has interrogated the different steps of this process, such as how the nanocrystal and enzyme fit together, how the nanocrystal generates an electron when exposed to light, how the nanocrystal transfers the electron to the enzyme, and how the enzyme uses those electrons to make hydrogen. It is only through building this comprehensive understanding of the steps that underpin this reaction that the team are in the position to provide a holistic picture of the whole transformation. Furthermore, the framework that they have built is robust enough to be applied in improving other light-driven reactions in the future.

This work describes an improved assembly line capable of converting light energy into hydrogen gas, a clean burning fuel that provides new, more efficient ways, to generate electricity. Perhaps more excitingly, it demonstrates the power of a new computational model and framework, built on over a decade of collaborative research, which has been made freely available, that provides insights into light-driven reactions and can be used by the scientific community to refine and optimize future light-driven chemistry. Helena Keller, the lead author is enthusiastic about the next steps “We are in a really exciting place now, where the capabilities of using computational methods to understand complex systems like this are becoming more and more accessible. The better we understand how to control processes at the smallest scales – like at the level of individual electron transfers – the closer we get to revolutionizing the way we produce energy and materials for the good of the world”.

June 2025

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Air-Enabled Electricity-Driven Depolymerization of Polyesters

Daniel Morton — Sun, 13 Apr 2025 19:26:24 +0000

Air-Enabled Electricity-Driven Depolymerization of Polyesters Daniel Morton Sun, 04/13/2025 - 13:26

ACS SUSTAINABLE CHEMISTRY & ENGINEERING, 2025, 13, 16, 5818-5827

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Single-Molecule Fluorescence Microscopy Reveals Energy Transfer Active versus Inactive Nanocrystal/Dye Conjugate Pairs

Daniel Morton — Mon, 07 Apr 2025 21:56:48 +0000

Single-Molecule Fluorescence Microscopy Reveals Energy Transfer Active versus Inactive Nanocrystal/Dye Conjugate Pairs Daniel Morton Mon, 04/07/2025 - 15:56

CHEMICAL AND BIOMEDICAL IMAGING, 2025, ASAP

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Electrostatic Work Causes Unexpected Reactivity in Ionic Photoredox Catalysts in Low Dielectric Constant Solvents

Daniel Morton — Thu, 03 Apr 2025 20:25:22 +0000

Electrostatic Work Causes Unexpected Reactivity in Ionic Photoredox Catalysts in Low Dielectric Constant Solvents Daniel Morton Thu, 04/03/2025 - 14:25

THE JOURNAL OF PHYSICAL CHEMISTRY B, 2025, 129, 15, 3895-3901

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Assigning Surface Hole Polaron Configurations of Titanium Oxide Materials to Excited-State Optical Absorptions

Daniel Morton — Tue, 04 Mar 2025 20:18:55 +0000

Assigning Surface Hole Polaron Configurations of Titanium Oxide Materials to Excited-State Optical Absorptions Daniel Morton Tue, 03/04/2025 - 13:18

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2025, ASAP

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Do Small Hole Polarons Form in Bulk Rutile TiO2?

Daniel Morton — Mon, 24 Feb 2025 22:47:23 +0000

Do Small Hole Polarons Form in Bulk Rutile TiO2? Daniel Morton Mon, 02/24/2025 - 15:47

THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 2025, 16, 9, 2333-2339

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Cation Crossover Limits Accessible Current Densities for Zero-Gap Alkaline CO2 Reduction to Ethylene

Daniel Morton — Wed, 08 Jan 2025 17:13:53 +0000

Cation Crossover Limits Accessible Current Densities for Zero-Gap Alkaline CO2 Reduction to Ethylene Daniel Morton Wed, 01/08/2025 - 10:13

ACS SUSTAINABLE CHEMISTRY & ENGINEERING, 2025, 13, 2, 823-833

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Anodic Hydrogen Generation from Benzaldehyde on Au, Ag, and Cu: Rotating Ring-Disk Electrode Studies

Daniel Morton — Mon, 30 Dec 2024 17:18:37 +0000

Anodic Hydrogen Generation from Benzaldehyde on Au, Ag, and Cu: Rotating Ring-Disk Electrode Studies Daniel Morton Mon, 12/30/2024 - 10:18

JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2024, 171, 12, 126507

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Catalyzing the Sustainable Decomposition of PFAS Forever Chemicals

Daniel Morton — Sat, 21 Dec 2024 00:30:44 +0000

Catalyzing the Sustainable Decomposition of PFAS Forever Chemicals Daniel Morton Fri, 12/20/2024 - 17:30

Daniel Morton

RASEI Fellow Niels Damrauer is part of a collaborative team that have developed a new light-driven C-F activation reaction, one that has the potential to help dismantle PFAS ‘forever chemicals’

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Highlight in The Conversation

C&EN Highlight

Colorado Arts and Science Magazine Highlight

Perfluoroalkyl and polyfluoroalkyl substances, or PFAS, are synthetic compounds that have found widespread use in consumer products and industrial applications. Their water and grease resistant properties have been part of their attraction in their applications, but these are also the reason that they are now found practically everywhere in the environment, they are very difficult to decompose.

While many chemicals will decompose relatively quickly, studies have shown that PFAS are expected to stick around for up to 1000 years. While this durability is great in something like firefighting foams or non-stick cookware, it is not great when these compounds get into the environment.

This new article, published in Nature in November of 2024, describes the work of a collaborative team of theoretical and experimental chemists, who have developed a new photochemical reaction that could hold promise of speeding up the decomposition of PFAS. A recent highlight of this work, written by the graduate student and postdoctoral fellows who did the research, appeared in The Conversation.

Using a photocatalyst, that absorbs light to speed up a reaction, the researchers were able to ‘activate’ one of the carbon-fluorine bonds, one of the strongest bonds in organic chemistry. The photocatalyst absorbs light, transfers electrons to the fluorine containing molecules, which then breaks down the sturdy carbon-fluorine bond.

While this doesn’t decompose the whole molecule, it is essentially like finding a chink in the armor, it opens the door to degradation of the PFAS to harmless smaller molecules.

This study demonstrated this process on a small scale, and the researchers are looking at how to optimize this reaction so it is more robust and can be done on larger scales. This work is part of a National Science Foundation funded Center for Chemical Innovation called SuPRCat, a research community that will be looking at this challenge, among others.

If it is possible to break down these forever chemicals, it will help prevent these environmental pollutants being in our soil, rivers, and drinking water. Excited to see the next steps from the team!

December 2024

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Bulk Layering Effects of Ag and Cu for Tandem CO2 Electrolysis

Daniel Morton — Tue, 26 Nov 2024 03:31:02 +0000

Bulk Layering Effects of Ag and Cu for Tandem CO2 Electrolysis Daniel Morton Mon, 11/25/2024 - 20:31

CHEMSUSCHEM, 2024, e202401769

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