Synopsis

A Sunny Path to Green Hydrogen

Physics 17, s21
A theoretical study of metal oxides identifies potential candidate materials for generating hydrogen fuel from water and sunlight.
Shutter81/stock.adobe.com

The dream of a green hydrogen economy rests on finding materials that can efficiently use sunlight to split water into hydrogen and oxygen. Ismaila Dabo from Pennsylvania State University and his colleagues have now performed a new theoretical search for these so-called photocatalysts, targeting a special type of metal oxide [1]. They found nine promising candidates, three of which have never previously been considered for water-splitting applications. The results highlight a material properties trade-off that might guide future photocatalyst development.

Hydrogen-powered cars and other vehicles could produce zero greenhouse-gas emissions. However, current hydrogen production relies on fossil fuels. Eco-friendly alternatives exist, but they must achieve water-splitting efficiencies of more than 10% to be cost competitive, Dabo says. To find those options, Dabo and his colleagues screened a database of metal oxides. The team targeted 109 oxides that contained both p-block (for example, indium and lead) and s-block (for example, cesium and calcium) elements, as previous work had found that this combination exhibits good water-splitting properties [2].

The researchers performed band-structure calculations to identify target oxides with strong solar absorption. They then selected oxides on the basis of the materials’ predicted electron-transfer properties, which are relevant to water-splitting reactions. They also looked at the materials’ water stabilities, as an ideal material shouldn’t degrade in water. Applying all these criteria, they found nine potential candidates, but the estimated efficiencies were all below 10%. Dabo and colleagues find that higher efficiency materials tend to be less stable in water. Considering this trade-off, they suggest structuring metal oxides with a highly efficient molecular core surrounded by a protective water-stable shell.

–Michael Schirber

Michael Schirber is a Corresponding Editor for Physics Magazine based in Lyon, France.

References

  1. S. Gelin et al., “Ternary oxides of s- and p-block metals for photocatalytic solar-to-hydrogen conversion,” PRX Energy 3, 013007 (2024).
  2. Y. Xiong et al., “Optimizing accuracy and efficacy in data-driven materials discovery for the solar production of hydrogen,” Energy Environ. Sci. 14, 2335 (2021).

Subject Areas

Energy Research

Related Articles

Testing a New Solar Sandwich
Energy Research

Testing a New Solar Sandwich

By combining the world’s oldest photovoltaic material with today’s most used one, researchers have taken a step toward next-generation solar devices. Read More »

Harness Strain to Harvest Solar Energy
Condensed Matter Physics

Harness Strain to Harvest Solar Energy

The engineering of structural deformations in light-sensitive semiconductors can boost the efficiency of solar cells. Read More »

Inertial-Confinement Fusion without Lasers
Energy Research

Inertial-Confinement Fusion without Lasers

The recent breakthroughs in laser-based fusion have given a boost to a number of start-up companies—one of which has plans to replace the lasers with a high-speed projectile. Read More »

More Articles