Construction of graphene supported TiO2 nanosheet array/CdS/Ni2P composite with dual heterojunctions for boosting photocatalytic hydrogen evolution

Abstract

Graphene supported TiO 2 nanosheet array (GT) was successfully fabricated via a hydrothermal route and modified by CdS and noble-metal-free Ni 2 P cocatalyst. It is found that interlaced TiO 2 nanosheets with a thickness only ca. 12.7 nm are vertically grown on graphene surface, which greatly reduce the agglomeration of nanosheets and provide abundant anchoring sites for surface modification. The synthesized GT/CdS/Ni 2 P (GTCN) composite exhibits superior photocatalytic hydrogen evolution rate of 1.91 mmol h −1 g −1 , which is ca. 11.7-fold higher than that of GT. Density functional theory calculation and experimental results reveal the formation of TiO 2 /CdS S-scheme heterojunction and CdS/Ni 2 P Schottky heterojunction in GTCN composite, and the constructed dual heterojunctions with intimate interfaces offer double transfer channels for photogenerated electrons, which effectively improved the photocatalytic reaction kinetics and facilitated the photogenerated carrier separation. This work provides insight into the design and construction of multicomponent catalysts with ideal photocatalytic performance for hydrogen evolution. • Graphene supported TiO 2 nanosheet array/CdS/Ni 2 P composite were synthesized. • Interlaced TiO 2 nanosheets with thin thickness are vertically grown on graphene. • TiO 2 nanosheet array provides abundant anchoring sites for surface modification. • Intimate dual heterojunctions facilitate carrier separation and enhance kinetics. • The hydrogen production rate of GTCN is as high as 1.91 mmol h −1 g −1 .