New hydrogen-evolution heteronanostructured photocatalysts: Pt-Nb 3O7(OH) and Cu-Nb3O7(OH)

Abstract

Nanorods of triniobium hydroxide heptaoxide, Nb3O 7(OH), were synthesized by means of a hydrothermal method. Subsequently, Pt and CuO nanoparticles were introduced on the surface of Nb 3O7(OH) nanorods by a microwave-assisted solvothermal nucleation and growth technique. The resulting Pt- and CuO-decorated Nb 3O7(OH) nanorods demonstrated uniform particle dispersion and were fully characterized by X-ray diffraction, electron microscopy, and spectroscopic analysis. Furthermore, the solar-powered photocatalytic hydrogen production properties of these heteronanostructures were studied. The solar-driven H2 formation rate over Pt-Nb3O 7(OH) was determined to be 710.4±1.7 μmol g-1 h-1 with a quantum efficiency of φ=5.40 % at λ=380 nm. Interestingly, the as-prepared CuO-Nb3O7(OH) heteronanostructure was found to be inactive under solar irradiation during an induction phase, whereupon it undergoes an in situ photoreduction process to form the photocatalytically active Cu-Nb3O7(OH). This restructuring process was monitored by an in situ measurement of the time-evolution of the optical absorption spectra. The solar-powered H 2 production for the restructured compound was determined to be 290.3±5.1 μmol g-1 h-1. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.