Biomolecule-mediated hydrothermal synthesis of polyoxoniobate-CdS nanohybrids with enhanced photocatalytic performance for hydrogen production and RhB degradation.

Using a biomolecule of l-cystine as the sulfur source and coordinating agent, polyoxoniobate-CdS nanohybrids were successfully synthesized under mild hydrothermal conditions. The adsorption of ammonium group (-NH2) in l-cystine molecular structure on the surface of CdS renders the amine-anchored CdS positively charged, which readily combines with the negatively charged polyoxoniobate clusters in terms of the electrostatic interaction. The as-obtained polyoxoniobate-CdS nanohybrids exhibit much superior activity for H2 evolution and RhB degradation under visible light as compared to the unhybridized CdS and polyoxoniobate. After co-loading Nb6 and NiS as cocatalyst, the H2-evolution activity of the nanohybrids is further increased up to 39 times as high as that of naked CdS, which can be attributed to an enhanced electron-transfer by adopting polyoxoniobate as electron-acceptor to retard the electron-hole recombination. The work may open an avenue for the green synthesis of cost-effective POMs-CdS nanohybrid photocatalysts for solar energy applications.