Colloidal Cd(x)Zn(1−x)S nanocrystals as efficient photocatalysts for H(2) production under visible-light irradiation

Cd(x)Zn(1−x)S nanocrystals with sizes ranging from 3–11 nm were synthesized by a simple organic solution method. The nanocrystals possess a cubic zinc-blende structure and the bandgap blue-shifts from 2.1 eV to 3.4 eV by increasing the composition of Zn ions in the solid solutions. After a facile ligand exchange process, the photocatalytic activity for H(2) production of the Cd(x)Zn(1−x)S nanocrystals was investigated under visible-light irradiation (λ ≥ 420 nm) with Na(2)SO(3)/Na(2)S as the electron donor. It was found that the Cd(0.8)Zn(0.2)S had the highest photoactivity with H(2) evolution rate of 6.32 mmol g(−1) h(−1). By in situ adding Pt precursors into the reaction solution, inhomogenous Pt–Cd(x)Zn(1−x)S nanoheterostructures were formed, which accounted for a 30% enhancement for the H(2) evolution rate comparing with that of pure Cd(0.8)Zn(0.2)S nanocrystals. This work highlights the use of facile organic synthesis in combination with suitable surface modification to enhance the activity of the photocatalysts.