Facile One-Pot Solvothermal Synthesis of Noble Metal-Free NiS Modified In2S3-Based Photocatalyst for Highly Efficient Visible-Light-Driven Cr6+ Removal

Rapidly electrons transferring of noble metal-free electron mediator NiS modifying In2S3 photocatalysts were synthesized through a one-pot hydrothermal method. Light with longer wavelength scope and stronger intensity can be absorbed and achieving more rapidly electrons transportation speed. PL and photocurrent spectra demonstrating that NiS-In2S3 composites have higher charge carrier separation efficiency. HRTEM revealed that NiS and In2S3 were contacted in nano size and have intimate contact with each other. XPS further proved there has an influence of the banding energy between NiS and In2S3. 10 % content sample achieving complete removal of Cr6+ with a trace photocatalyst concertation (0.2 mg/mL) within 30 min which was 3 times higher than pure In2S3. The proper mechanism was proposed that In2S3 was excited by visible light to produce electron-hole pairs, and NiS acted as a light absorbing intensifier and electron trapper conducting electrons from the In2S3 conduction band to the surface of composites and then reacting with the active species, thus improving the charge carrier separation efficiency and photocatalytic activity