Abstract
This work focuses on the development of a novel organic–inorganic photoactive material composited by aggregation-induced emission luminogens (AIE) and CdS. Tetraphenylethene-based AIE (TPE-Ca) is synthesized on CdS to form CdS/TPE-Ca electrode, due to its suitable band structure and potential capability of renewable energy production. The CdS/TPE-Ca electrode presents over three-fold improved photocurrent density and dramatically reduced interfacial resistance, compared with the pure CdS electrode. In addition, the engineering of the band alignment allows the holes to accumulate on the valance band of TPE-Ca, which would partially prevent the CdS from photo-corrosion, thus improving the stability of the sacrificial-free electrolyte photoelectrochemical cell.
Highlights
As a valuable subgroup of semiconductive photocatalysts, transition-metal sulfides typically possess narrower band gaps than that of metal oxides, which makes them capable of various useful redox reactions under mild conditions, for instance, water splitting [1,2], high-energy-density supercapacitors [3,4], lithium-sulfur batteries [5], sodium ion battery anodes [6], for photovoltaic and photoelectrochemical devices [7]
High-resolution transmission electron microscopy (HR-TEM) was exploited to identify the CdS/TPE-Ca, in which the lattice fringes and selected area electron diffraction (SAED) results were consistent with the crystal structures of CdS and TPE-Ca, respectively
Linear sweep voltammetry (LSV) measurements were carried to evaluate the photoactivity of the as-prepared electrodes
Summary
As a valuable subgroup of semiconductive photocatalysts, transition-metal sulfides typically possess narrower band gaps than that of metal oxides, which makes them capable of various useful redox reactions under mild conditions, for instance, water splitting [1,2], high-energy-density supercapacitors [3,4], lithium-sulfur batteries [5], sodium ion battery anodes [6], for photovoltaic and photoelectrochemical devices [7]. An alternative strategy to hamper the photo-corrosion of CdS is constructing suitable heterostructure photocatalysts, to transfer the photo-generated holes to the valance band (VB) of the coupled materials. This approach will protect the CdS, but can potentially enhance the charge separation and light absorption. To improve the photocatalytic efficiency of organic photocatalysts, the key approach is to reduce the non-radiation pathway and transfer the photogenerated electrons and holes. We report a novel CdS/TPE-Ca heterostructure photocatalyst with outstanding photoactivity and stability for hydrogen evolution in the absence of a sacrificial reagent. The photoelectrochemical features of the composite photocatalyst is carried out and found to benefit from the rapid charge carrier’s migration
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