Chinese scientists set new efficiency record for solar-to-hydrogen conversion

TIANJIN, June 18 (Xinhua) -- Researchers at China's Tianjin University have achieved a milestone in solar-powered hydrogen production, developing a semi-transparent photoanode that pushes solar-to-hydrogen (STH) conversion efficiency to a record 5.1 percent.

The breakthrough, published in Nature Communications, offers a promising pathway for scalable "artificial leaf" technology, reported Science and Technology Daily on Tuesday.

"Artificial leaves" are silicon-based devices using solar energy to split hydrogen and oxygen in water, thereby producing hydrogen energy in a clean way.

Led by Wang Tuo, a professor from the School of Chemical Engineering and Technology, the research team addressed critical limitations in unbiased solar water splitting systems, which produce hydrogen without external voltage.

Their innovative indium sulfide (In₂S₃) photoanode overcomes the traditional trade-off between conductivity and light transparency.

"Our semi-transparent design simultaneously accelerates the water oxidation reaction and allows photons to reach the photocathode, minimizing energy waste," said Wang, corresponding author of the study.

Validated in a fully solar-driven standalone system, the device achieved 5.1 percent STH efficiency, surpassing the 5 percent benchmark for conventional systems using silicon photocathodes with inorganic photoanodes. This marks the highest reported efficiency for such configurations, said Wang.

The research provides novel solutions to two persistent challenges: sluggish interfacial electron transfer and significant optical losses.

With further optimization, the technology is expected to open avenues for developing cost-effective, durable "artificial leaves."

Potential applications of the "artificial leaves" include hydrogen-generation units integrated into building facades, rooftops, or desert-based production plants, said Wang. ■