Photocatalysis is one of promising methods to convert solar energy into chemical fuels. The supported metal nanoparticles (NPs) are extensively used as photocatalysts. However, metal NPs with ultrafine sizes are prone to aggregate during preparation and catalytic application owing to their high surface energy.

In a study published in Energy & Environmental Science, the research group led by Prof. WANG Ruihu from Fujian Institute of Research on the Structure of Matter (FJIRSM) of Chinese Academy of Sciences (CAS) reported a facile and general approach for the in situ growth of Ru NPs on TiO₂ encapsulated by nitrogen-doped carbon materials.

The imidazolium-based ionic polymer (ImIP) was selected as the precursors of nitrogen-doped carbon. Ru could be introduced through simple anion exchange.

Researchers found that the sintering of Ru NPs is effectively inhibited by ImIP during pyrolysis, generating ultrafine and well-dispersed Ru NPs.

They also revealed that the nitrogen-doped carbon in TiO₂@NC-Ru-T both strengthens the performance of Ru NPs and facilitates photoelectron transfer from photoactivated Ru NPs to TiO₂, which results in great promotion for selective aerobic oxidation of alcohols under visible light irradiation.

This study provides one type of new metal/semiconductor heterojunction materials with low Schottky barrier and ultrastable small-size metal NPs.

The synthetic strategy could be extended to a broad range of phototcatalysts consisting of other noble metals and semiconductors for various organic photosynthesis.

The schematic illustration for the synthesis of TiO₂@NC-Ru-T. (Image by Prof. WANG’s Group)