Efficient Self‐Assembly Synthesis of Uniform CdS Spherical Nanoparticles‐Au Nanoparticles Hybrids with Enhanced Photoactivity

Abstract

The treatment of environmental pollution has become one of the most critical issues in the world. Despite the progress made in the study of semiconductor photocatalysis, it is still a challenge to obtain photocatalysts with high activity through relatively simple fabrication processes. In this work, monodisperse CdS spherical nanoparticles (SNPs) of various sizes and good crystallinity are obtained by only adjusting the starting ratio of reactants and the reaction temperature, exhibiting high photocatalytic performances. The photocatalytic rate constant of the ≈ 100 nm CdS SNPs, especially, is more than double that of P25. Furthermore, 3-mercaptopropyltrimethoxysilane is used to assist the interaction between ≈ 200 nm CdS SNPs and citrate-stabilized Au nanoparticles (NPs). The signifi cant increase of photocatalytic activity is confi rmed by the degradation of Rodamine B (RhB) under Xe light irradiation. At the optimal Au concentration (0.5 wt%), the prepared nanohybrids show the highest photocatalytic activity, exceeding that of pure CdS two times. The superior photocatalytic performances of the CdS SNPs-Au nanohybrids can be attributed to the intimate interfacial contact between CdS SNPs and Au NPs, which is a contributing factor to the improvement of transfer and the fate of photogenerated charge carriers from CdS SNPs to Au NPs.

Au nanoparticle-decorated ultrathin CdS nanowires for high-efficiency photodegradation of organic dyes

“…The remarkable quenching of PL spectra shows that Au NPs play an important role in the photogenerated charges transfer process [35,36]. Similar quenching of PL spectra has been observed in previous reports such as AuZnS [37] and Au-CdS [8,36], due to the efficient separation of photoinduced electrons and holes. In the transfer process, Au NPs act as electron acceptors.…”

“…The diffraction peak at 38.2°is the (111) peak of metallic gold (JPCDS.04-0784). This indicates that Au NPs have good crystallization and benefit for the transfer of photogenerated electrons [8]. The samples composed of different amounts of Au NPs have similar XRD patterns.…”

Au/SnS2 Hybrid Quantum Dots for Surface-Enhanced Raman Scattering-Based Monitoring and Photoreduction of Hg (II) Ions

“…When exposed to visible light, electrons in the SnS 2 VB are excited to the CB, by leaving an equal number of holes behind. As per the studies reported earlier, the excess electrons in the CB of SnS 2 can be transferred to Au due to the potential energy difference, , and these surface electrons can facilitate the Hg (II) photoreduction process. The O 2 molecules that are absorbed on the Au/SnS 2 surface are reduced by the Au electrons to generate superoxide radicals ( •– O 2 ).…”

Strong Visible Light Absorption and Abundant Hotspots in Au-Decorated WO3 Nanobricks for Efficient SERS and Photocatalysis

“…Upon light irradiation, electrons in the valence band (VB) of WO 3 are excited to the conduction band (CB), and the same number of holes are generated in the VB. Driven by potential energy, the photogenerated electrons in the CB of WO 3 can be transferred to Au, which has been reported in previous studies. , In the photocatalytic processes, the electrons on Au can directly react with the adsorbed O 2 on the surface of samples to produce O 2– . Additionally, the photogenerated electrons on WO 3 are transferred to Au to offer more electrons for the reduction reaction.…”