Synthesis of hollow core-shell CdS@TiO2/Ni2P photocatalyst for enhancing hydrogen evolution and degradation of MB

Abstract

During the photocatalytic production of hydrogen gas, close interface with a catalyst is very important. We designed a noble-metal-free photocatalytic system that is spatially separated to produce hydrogen by high frequency visible light. We used a new type of a catalyst consisting of hollow core-shell CdS@TiO2/Ni2P structures prepared using sacrificial template method. Photocatalytic decomposition of water was tested using this catalyst. Hydrogen production yield using 420 nm light was 14.80 mmol/g after 2.5 h and using Xe lamp with AM1.5G filter was 34.78 mmol/g after 2.5 h. Hollow core shell CdS@TiO2/Ni2P particles were more stable than hollow core shell CdS@TiO2/Pt structures because TiO2 protected CdS from photo-corrosion. Combination of CdS and Ni2P increased absorption range of TiO2 at 720 nm. Holes and electrons produced during the photo-reaction can migrate to the CdS on the inside and to the Ni2P on the outside of the TiO2 protective coating. Such design exposes more surface, thus, increases hydrogen production.