A C@TiO2 yolk-shell heterostructure for synchronous photothermal-photocatalytic degradation of organic pollutants

Environmental contamination, especially water pollution, is acknowledged as one of the most urgent global challenges. In essence, surface reactive oxygen species (ROS) is crucial for the photocatalytic degradation of organic pollutants in wastewater. Recently, the direct conversion of clean and renewable solar energy to heat to drive the activation process of oxygen is a highly effective and desirable way to use solar energy. However, it still remains a challenge to develop a flexible and versatile method to enhance the efficiency of photocatalysis. Herein, we report a new strategy for designing and constructing a C@TiO2 yolk-shell (YS) heterostructure with excellent photo-thermal conversion ability to achieve highly photo-thermal catalytic degradation of RhB under visible light irradiation, consisting of a tunable hydrothermal carbon sphere (CS) core covered by TiO2 shells. This approach integrates the hetero-interfacial charge carrier management, the photothermal excitation of the CS core and the injection of hot electrons into the TiO2 shells, leads to reliably boosted hot electron generation and transfer, and further promotes the activation of dissolved oxygen in water, consequently enhancing the visible light driven catalysis. The YS architecture and the photothermal effect interplay of the C@TiO2 heterostructure are comprehensively studied and optimized. Such a YS heterostructure photo-thermocatalyst concept provides a novel approach for effective utilization of solar energy, and coupling with the CS photothermal effect in a traditional catalytic process is a promising strategy for large-scale environmental and energy applications.