Preparation and degradation dyestuffs performance of HCS@TiO₂ photocatalytic composites

In order to obtain more efficient photocatalytic materials, hollow carbon sphere (HCS)@TiO₂ photocatalytic composites was prepared by a facile wet-chemical method and characterized. The results of structural and morphology characterization showed that TiO₂ nanoparticles were anchored uniformly on the surface of HCS, forming a spherical composites with high hydrophilia and specific surface area and excellent thermostability, the mass percentage of TiO₂ anchored on HCS@TiO₂ composites was 80wt%. The analysis of photoelectric chemical properties showed that HCS@TiO₂ composites had smaller bandgap width, wider light response range, and stronger photogenic electron reduction ability. Using Reactive Red 195 (RR195) as the experimental object, the photocatalytic degradation dyes performance and cyclic stability of HCS@TiO₂ composites were tested under simulated sunlight. The results show that the separation efficiency of photogenic electron hole pairs in the HCS@TiO₂ is higher, and the photocatalytic activity is excellent. The degradation rate is 95.36% within 120 min, and it still reaches 93.34% after 5 cycles, with high stability and easy recovery. At the same time, the photocatalytic mechanism of HCS@TiO₂ photocatalytic composites was proposed by combining free radical capture experiment and electron paramagnetic resonance spectroscopy. It was confirmed that \text•\rmO_2^ - plays a major role in the photocatalytic reaction system.