Highly Efficient Visible-Light-Driven Photocatalytic Hydrogen Production of CdS-Cluster-Decorated Graphene Nanosheets

Abstract

The production of clean and renewable hydrogen through water splitting using photocatalysts has received much attention due to the increasing global energy crises. In this study, a high efficiency of the photocatalytic H(2) production was achieved using graphene nanosheets decorated with CdS clusters as visible-light-driven photocatalysts. The materials were prepared by a solvothermal method in which graphene oxide (GO) served as the support and cadmium acetate (Cd(Ac)(2)) as the CdS precursor. These nanosized composites reach a high H(2)-production rate of 1.12 mmol h(-1) (about 4.87 times higher than that of pure CdS nanoparticles) at graphene content of 1.0 wt % and Pt 0.5 wt % under visible-light irradiation and an apparent quantum efficiency (QE) of 22.5% at wavelength of 420 nm. This high photocatalytic H(2)-production activity is attributed predominantly to the presence of graphene, which serves as an electron collector and transporter to efficiently lengthen the lifetime of the photogenerated charge carriers from CdS nanoparticles. This work highlights the potential application of graphene-based materials in the field of energy conversion.

Fabrication of flexible and freestanding zinc chalcogenide single layers

“…Obviously, their ultraflexible features could achieve an intimate contact with the indium tin oxide (ITO) substrate, hence, facilitating electrons to effectively circulate through the external circuit. Moreover, benefited from a larger contact area with electrolyte, the ZnSe single layers allowed surface reactions to take place across a much bigger area, greatly enlarging the reaction space 29 . By contrast, as for bulk counterpart, the large and irregular shapes result in many grain boundaries and poor contact with substrate, which leads photoexcited electrons to diffuse through countless recombination centres before reaching the photoelectrodes, thus causing loss of the vast majority of those charge carriers.…”

Enhanced photoelectrochemical and photocatalytic activities of CdS nanowires by surface modification with MoS2 nanosheets

“…As one of the potential promising candidates for visible light driven photocatalysis, cadmium sulfide (CdS) has been widely studied owing to its proper bandgap (E g = 2.42 eV) for efficient absorption of visible light [12], and its valence and conduction band positions being thermodynamically favorable for water oxidation and reduction, respectively [13]. However, the low activity and rapid photocorrosion make pure CdS photocatalyst unfavorable for hydrogen evolution reaction (HER) because photogenerated electron and hole pairs cannot be efficiently separated and transferred [14,15].…”

One-pot microwave-assisted colloidal synthesis of Ag2O/ZnO/nanographene platelets composites: Photocatalytic studies

“…1(b). It was suspected that it owes to fewer active sites from the surface of Ag2O/ZnO catalysts which is covered by an excess of NGP and so-called "shielding effect" [11]. Besides, the attenuation of light irradiation through the covered NGP on active sites lessens the photo-absorption efficiency.…”