Synthesis of Morphology-Tunable PbS-Pt-TiO2 Nanohybrids with Strong Light Absorption and Enhanced Photothermal and Photocatalytic Degradation Performance

Multicomponent heterojunctions have attracted considerable attention for the potential applications in photodriving applications. However, the limited number of active sites on the surface and the rapid recombination of photogenerated carriers restrict the improvement of the performance of photothermal conversion and photocatalytic degradation. Here, a ternary nanohybrid composed of PbS, Pt, and TiO2 is presented for the first time. PbS nanocrystals evolved from octahedral to a unique 24-faceted morphology were monitored and described systematically. Then, they were selectively deposited by Pt nanoparticles and coated with a TiO2 thin nanoshell. Under 808 nm near-infrared laser irradiation, the photothermal conversion performance and photocatalytic reduction rates of these nanohybrids were investigated in depth. Among them, the PbS-Pt-TiO2 nanohybrids exhibited the highest photothermal conversion efficiency and fastest degradation speed of Rhodamine B when compared to PbS-Pt and pure PbS, which are attributed to the effective light absorption of 24-faceted PbS nanocrystals and the outer TiO2 shell, the abundant catalytic active sites provided by Pt nanoparticles, and the excellent separation and transportation efficiency of hot carriers between different components.