A strategy for in-situ synthesis of well-defined core–shell Au@TiO2 hollow spheres for enhanced photocatalytic hydrogen evolution

• A facile in-situ hydrothermal reduction technique to synthesize Au@TiO2 core–shell hollow sphere.
• The optimum weight percentage of Au is 2.0 wt% for photocatalytic H2 evolution.
• The H2 evolution rate for Au@TiO2 is 7 times higher compared to Au-P25 under solar light radiation.
• Pt@TiO2 and Au@ noble metal core shell hollow spheres are also fabricated via this approach.

This work reports a simple strategy to prepare Au@TiO2 core–shell hollow spheres with well-defined morphology by combining an in-situ hydrothermal reduction technique with the adsorption of Ti4+ ions onto carbon spheres via a hard template strategy. H2 evolution measurements suggest that the prepared Au@TiO2-2 (2.0 wt%) hollow spheres exhibited remarkable H2 evolution activity (7 times) compared to Au-P25 under ultra violet irradiation. The enhanced photocatalytic efficiencies are attributed to the large surface area of Au@TiO2, with the encapsulated Au NPs acting as co-catalyst. In addition, an enhanced surface plasmonic resonance (SPR) effect by the Au NPs resulted in better light absorption of the hollow structure. This synthesis strategy can also be extended to other types of core–shell hollow composites (Pt@TiO2 and Au@Fe2O3). This would open a new avenue for the development of well-defined core–shell hollow structures for various applications, including hydrogen generation.