Nanotechnology

Organic chemistry

Hydrogen

Photocatalysis

Crystallography

Visible spectrum

Semiconductor

Nanorod

Engineering

Catalysis

Photocatalytic water splitting

Chemistry

Materials science

Water splitting

Chemical engineering

Optoelectronics

Biochemistry

Single crystal

Photochemistry

Nature Catalysis

Although one-step-excitation overall water splitting on a particulate photocatalyst is a simple means of performing scalable solar-to-hydrogen energy conversion, there is a lack of photocatalysts with significant activity under visible light. Despite its superior visible-light absorption, the Ta3N5 photocatalyst has not accomplished overall water splitting due to strong charge recombination at defects. Here, we show rapid growth of Ta3N5 nanorods on lattice-matched cubic KTaO3 particles through the volatilization of potassium species during a brief nitridation process. The Ta3N5 nanorods generated selectively on the edge of KTaO3 are spatially separated and well-defined single crystals free from grain boundaries. When combined with the Rh/Cr2O3 co-catalyst, the single-crystal Ta3N5 nanorods split water into hydrogen and oxygen very efficiently under visible light and simulated sunlight. Our findings demonstrate the importance of nanostructured single-crystal photocatalysts free from structural defects in solar water splitting. Ta3N5 is a semiconductor with very promising photocatalytic properties. However, performing overall water splitting with this material has remained elusive. Now, Domen and co-workers report a method for the synthesis of defect-free single-crystal Ta3N5 nanorods capable of splitting water into hydrogen and oxygen in the presence of a co-catalyst.

Overall water splitting by Ta3N5 nanorod single crystals grown on the edges of KTaO3 particles