By Faridat Salifu
A team of scientists from the Institute of Science Tokyo and Hiroshima University has achieved a major breakthrough in solar fuel technology, developing a new catalyst that increases hydrogen production efficiency by up to 60 times.
The innovation sets new performance records in photocatalysis by harnessing sunlight to convert water and carbon dioxide into hydrogen gas and formic acid, a liquid fuel.
At the heart of the breakthrough is a redesigned photocatalyst based on a lead-based oxyhalide compound known as Pb₂Ti₂O₅.₄F₁.₂ (PTOF), which had shown promise for visible-light-driven chemical reactions but previously delivered limited efficiency.
The Japanese team’s novel synthesis technique yields PTOF particles less than 100 nanometers in size, with a surface area of 40 m²/g — more than 15 times larger than that of conventionally produced particles.
This nanoscale engineering dramatically improves the material’s ability to absorb light and carry out surface-level reactions crucial to hydrogen and fuel generation.
The new catalyst achieves a record quantum yield of around 15% for hydrogen production and 10% for converting carbon dioxide into formic acid, surpassing all previously reported values for oxyhalide-based materials.
“These results establish world-leading performance for H₂ and CO₂ conversion using oxyhalide photocatalysts,” said Professor Kazuhiko Maeda, who co-led the study.
The research team used a low-temperature, microwave-assisted method and replaced conventional titanium sources such as TiCl₄ with specially selected water-soluble titanium complexes to achieve the required structure and purity.
Shrinking the particle size greatly reduces the distance that photoexcited charge carriers must travel to reach the surface, making them more likely to trigger useful reactions instead of recombining and losing energy.
While smaller particles often come with the trade-off of structural defects that hurt performance, the researchers’ method avoids this pitfall, preserving both stability and reactivity.
Importantly, the synthesis process is considered environmentally friendly and scalable, offering a potential route to commercial solar-to-fuel technologies.
The study is being hailed as a critical step forward in the quest to generate clean fuel from sunlight while addressing global challenges related to energy security and climate change.
In a related development, scientists in China have also reported record-setting progress in solar-to-hydrogen conversion using copper zinc tin sulfide (CZTS) photocathodes.
Using a new precursor seed layer engineering (PSLE) method, the Chinese team achieved a half-cell solar-to-hydrogen (HC-STH) efficiency of 9.91%, the highest ever reported for earth-abundant CZTS photocathodes.
Together, both breakthroughs highlight growing momentum in clean fuel research, with scientists worldwide racing to transform sunlight, water, and CO₂ into usable, storable energy forms.
