HMN 2026: How Standalone ‘leaf’ produces liquid fuel from sun, water and CO? with record efficiency

A Yale-led research team has developed the first standalone device that produces the liquid fuel methanol using only sunlight, water, and carbon dioxide as the ingredients. The artificial “leaf,” like its namesake in nature, is a chemistry marvel. It brings the scientific mimicry of photosynthesis—the process of converting sunlight and water into chemical energy—to a new level, converting sunlight to methanol 32 times more efficiently than the previous conversion record for artificial leaf technologies that generate alcohol products.

“This looks promising, with a concept that is comparable to what nature does,” said Hailiang Wang, a professor of chemistry in Yale’s Faculty of Arts and Sciences, member of the Yale Energy Sciences Institute and Yale Center for Natural Carbon Capture, and senior author of a new study published in the Journal of the American Chemical Society. “From the moment that we saw the first results it was super exciting.”

The new “leaf” offers several commercial and environmental benefits. It pulls carbon dioxide, a greenhouse gas and main contributor to climate change, from the air; it creates methanol, an increasingly popular chemical feedstock and alternative liquid fuel; and it suggests a viable new method for converting and storing solar energy.

The study is also a research milestone for the Center for Hybrid Approaches in Solar Energy to Liquid Fuels (CHASE), a solar energy research hub comprising seven U.S. research institutions and based at the University of North Carolina-Chapel Hill (UNC-Chapel Hill). In addition to Yale, the new study includes researchers from North Carolina State University-Raleigh, UNC-Chapel Hill, and the University of Pennsylvania.

Wang and Bo Shang, a student in Yale’s Graduate School of Arts and Sciences and a researcher in the Wang lab, led the design of the new system, which was part of Shang’s doctoral dissertation.

How the artificial leaf works

At the heart of the new system is a pair of discoveries made and refined over the past decade in the Wang lab: a unique catalyst and an innovative photoelectrode that combine for a more powerful, streamlined conversion process that may be scalable for wider use.

First came the catalyst, developed in 2019, that converts carbon dioxide and water into methanol using electricity. It’s a type of catalyst called a heterogeneous molecular electrocatalyst—”heterogeneous” because it’s a solid catalyst material operating in a liquid electrolyte, and “molecular” because the active site of the catalyst is a molecular structure.

The distinct structure of the catalyst is the key, Wang said.

He and his team anchored individual molecules of cobalt phthalocyanine (or its derivative) onto the surface of carbon nanotubes, nanometer-diametered tubes of rolled up graphene layers. The nanotubes act like a highway for electrons, creating a rapid and continuous delivery of electrons to the catalytic sites for converting carbon dioxide to methanol. It is a six-electron reduction process, the researchers said, meaning that six electrons are injected into one carbon dioxide molecule.

Prior to this discovery, a more limited delivery of electrons—a two-electron reduction process—meant molecular catalysts were only able to convert carbon dioxide into products such as carbon monoxide.

Building a more efficient device

Next came a photoelectrode, developed by Shang, consisting of an array of silicon micropillars coated with a layer of fullerene carbon. This structural design, which had a desirable geometry for charge generation and separation, a tailored interface for electron transfer, and an increased surface area for anchoring the catalyst, yielded the most efficient photoelectrocatalytic conversion of CO₂ to methanol, based on silicon, ever reported.

“When I started, getting a device like this to run on its own felt like a long shot,” said Shang, first author of the new study. “Over five years of work in CHASE, we developed every part of the device from the ground up. To watch it turn just sunlight, water, and CO₂ into a usable fuel is incredibly rewarding—and it really feels like only the beginning of what the approach can do.”

The research team continued improving the structure of its new leaf to boost conversion efficiency—a process that will continue now that the approach has proven to be effective, Wang said.

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