Constructing nanoparticle-assembled CdS microspheres on a FeVO4 nanopolyhedrons photoanode for enhanced photoelectrochemical performance

Improving the light energy utilization to augment the charge carrier concentration and modulating the band alignment to facilitate charge carrier transport and separation are essential for semiconductor photoanode to achieve high-efficiently photoelectrochemical (PEC) performance. Herein, a novel FeVO4 nanopolyhedrons photoanode modified by nanoparticle-assembled CdS microspheres is constructed through an in-situ solid-state transformation and a chemical bath deposition, successively, to augment the concentration of carriers by improving light utilization and facilitate efficient transport and separation of carriers by building type-II structure for efficient PEC performance. The constructed nanoparticle-assembled CdS microspheres modified FeVO4 nanopolyhedrons photoanode generates a drastic improvement in photocurrent, which is 29 times higher than that of pristine FeVO4 nanopolyhedrons photoanode at 0.4 V vs. Ag/AgCl under AM 1.5 G simulated solar light irradiation. The experimental measurements of light absorption evidence that the modification of nanoparticle-assembled CdS microspheres substantially improves light harvesting ability of FeVO4 nanopolyhedrons from 300 to 800 nm for substantially generating charge carriers. Spectral measurements of X-ray photoelectron spectroscopy evidence that a band alignment of type-II structure is established at FeVO4/CdS interface, building directional interface charge transport channel for efficient transfer and separation of photoinduced charge carriers. This study offers a referable strategy for designing photoanodes to achieve PEC performance from the perspective of light energy utilization and interface energetics engineering.