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

Abstract

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.