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

Abstract

• Assembly of hollow Tio 2 @CMS/carbon-fiber van der Waals heterostructures. • Electron transport from TiO 2 to carbon accelerates the separation of carriers. • The photocatalyst and photoelectrocatalyst are separable and recyclable. The recycling technology of photocatalyst powdery has hardly been mature in the photocatalytic oxidation so far. In this work, the hollow TiO 2 microspheres with an appropriate thickness are confined in carbon microspheres (CMSs) to form hollow TiO 2 @CMSs, which are physically integrated with carbon-fiber textile by van der Waals (vdW) interactions to generate separable and recyclable hollow TiO 2 @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 TiO 2 @CMSs and creates holes in hollow TiO 2 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 TiO 2 @CMSs/carbon-fiber vdW heterostructures can be used as separable and recyclable photocatalyst and photoelectrocatalyst with potential industrial applications in environment-related fields. The assembly of microsphere and carbon fiber to fabricate separable and recyclable van der Waals heterostructure to address the difficulty of separation and recycle powdery photocatalysts after usage.