Flexible hollow TiO2@CMS/carbon-fiber van der Waals heterostructures for simulated-solar light photocatalysis and photoelectrocatalysis

The recycling technology of photocatalyst powdery has hardly been mature in the photocatalytic oxidation so far. In this work, the hollow TiO2 microspheres with an appropriate thickness are confined in carbon microspheres (CMSs) to form hollow TiO2@CMSs, which are physically integrated with carbon-fiber textile by van der Waals (vdW) interactions to generate separable and recyclable hollow TiO2@CMSs/carbon-fiber vdW heterostructures. Such separable and recyclable heterostructures show remarkable oxidation of 2,4-dinitrophenol. From our detailed characterization and density functional theory (DFT) calculations, we found that carbon fiber can trap electrons exerted from the excitation of hollow TiO2@CMSs and creates holes in hollow TiO2 microspheres, which endow the carbon fiber with photocatalytic activity through coherent charge injection. This study indicates that our general strategy for the fabrication of hollow TiO2@CMSs/carbon-fiber vdW heterostructures can be used as separable and recyclable photocatalyst and photoelectrocatalyst with potential industrial applications in environment-related fields.