Two-dimensional ultrathin ZnxCd1-xS nanosheet with exposed polar facet by using layered double hydroxide template for photocatalytic hydrogen generation

Two-dimensional ultrathin Zn x Cd 1-x S nanosheet was fabricated by topotactic sulfurization process using trimetallic ZnCdAl layered double hydroxides (LDHs) as precursor and thiourea as sulfur source. A series of characterizations were conducted to investigate the structure and properties of Zn x Cd 1-x S nanosheet. The band gap engineering of Zn x Cd 1-x S nanosheet can be tuned by the composition of LDH precursor, keeping balance between photo-absorption ability and flat band potential. Zn x Cd 1-x S nanosheet possessed exposed (111)ZB or (002)WZ polar facet. Zn 0.67 Cd 0.33 S nanosheet displayed not only the highest photocatalytic hydrogen-generation activity under visible light irradiation (6.69 mmol h −1 g −1 ) without cocatalyst , but also outstanding stability after several cycles. In spite of the poor surface area of the nanosheet, it can be concluded that the carrier separation and transport rate of Zn x Cd 1-x S nanosheet significantly enhanced, rendering photogenerated carriers transport across the polar facet. This can be attributed to the photogenerated electron/hole exclusively delocalized distributed on the metal/sulfur ions, respectively. This work presents a strategy to fabricate highly efficient Zn x Cd 1-x S nanosheet from LDH precursor, which is a simple, low-cost and environmentally friendly process.