Research News

Researchers Realize Redox-driven Z-scheme Highly-efficient Overall Water Splitting under Visible Light Irradiation

Posted: 2024-01-17

Overall water splitting (OWS) using suspended particulate photocatalysts to produce green hydrogen is promising due to its cost-effective and easy large-scale application.

However, due to lack of inefficient cocatalysts and poor interface of cocatalyst and semiconductor, the challenging charge separation restricts the improvement of apparent quantum efficiency (AQE) under visible light.

Recently, a research group led by Prof. ZHANG Fuxiang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) revealed that the strong metal-support interaction (SMSI) could promote the interfacial charge separation and water oxidation activity of Ir/BiVO4 photocatalyst system, based on which they fabricated a highly-efficient redox-driven Z-scheme OWS system with a AQE of 16.9% at 420 ±10 nm under room temperature.

This study was published in Joule on Jan. 02.

The researchers obtained the Ir/BiVO4 photocatalyst with SMSI effect by high temperature hydrogen reduction treatment, and they verified that the SMSI could promote interfacial charge separation. In addition, by in-situ photoinduction, Ir species were converted into Ir and IrO2 dual-cocatalysts on the {010} and {110} facets of BiVO4, which further improved its surface catalysis and charge separation, leading the increased water oxidation performance of BiVO4 by more than 75 times.

On this basis, they constructed a photocatalytic Z-scheme OWS system with benchmarking AQE value of artificial photosynthesis using suspended powder photocatalyst, together with the TaON-based photocatalyst as H2-evolving photocatalyst and [Fe(CN)6]3-/4- as redox ion.

"This study not only extends the application of SMSI from the traditional thermal catalysis to the field of photocatalysis, but also provides a new idea for promoting photogenerated charge separation," said Prof. ZHANG.

This work was supported by the National Natural Science Foundation of China and the National Key R&D Program of China.