Sandwiched ZnO@Au@CdS nanorod arrays with enhanced visible-light-driven photocatalytical performance

Abstract

The development of high-performance photocatalysts is central to efforts focused on taking advantage of solar energy to overcome environmental and energy crises. Integrating different functional materials artfully into nanostructures can deliver more efficient photocatalytic activity. Here, sandwiched ZnO@Au@CdS nanorod films were synthesized via successive ZnO nanorod electrodeposition, Au sputtering and CdS electrodeposition. The as-synthesized composites were characterized by UV-vis spectrophotometer, x-ray diffractometer, scanning and transmission electron microscopy. Their photocatalytic activity was assessed by degrading Rhodamine B solution under visible light irradiation. ZnO@Au@CdS exhibited better photocatalytic performance than ZnO@CdS throughout the visible light region, and the corresponding enhancement factor of Au nanoparticles was measured as a function of CdS loading amount, and it could reach 190% with CdS deposition for 1 min. The normalized rate constant could reach 0.387 h for ZnO@Au@CdS-1min, which was equivalent to or better than results in reference photocatalysts. The enhancement mechanism of Au nanoparticles was estimated by comparing the monochromatic photocatalytic action spectra with the absorption spectrum of ZnO@Au@CdS, and it was mainly determined by incident photon energy. With selective excitation of Au nanoparticles by incident photons, the excited hot electrons in Au NPs are transferred to the conduction band of ZnO to boost photocatalytic reaction. With selective excitation of CdS, the enhanced interband absorption of CdS and relay station effect of Au nanoparticles should be responsible for the enhanced photocatalytic performance. Our work not only opens the door to the design of efficient supported photocatalysts, but also helps to understand the enhancement mechanism of LSPR effect on the photoelectric conversion of semiconductors.

Synthesizing CuO/CeO2/ZnO Ternary Nano-Photocatalyst with Highly Effective Utilization of Photo-Excited Carriers under Sunlight

“…For instance, by decorating precious metals such as Au, Ag on the MOSs (TiO 2 , ZnO, etc.) surface, the light absorption capacity, as well as the photo-response of semiconductor under UV and visible light excitation can be significantly enhanced because of the existence of schottky barrier and surface plasmon resonance (SPR) intrinsic to the metal [ 2 , 9 , 10 , 11 ]. However, metal incorporation cannot realize industrialization on account of high production costs.…”

Highly porous SnO2 nanosheet arrays sandwiched within TiO2 and CdS quantum dots for efficient photoelectrochemical water splitting

“…CdS quantum dots (QDs) have also been extensively employed as absorber guests in various hybrid photoanodes for PEC applications due to their suitable band structure and efficient visible light absorption. [19,[29][30][31][32] The uniform dispersion of CdS QDs on three dimensional SnO2 host skeletons has been reported for PEC water splitting, such as screw-like SnO2 nanostructures/CdS QDs. [33] However, the energy conversion efficiency of SnO2/CdS host-guest photoanodes is greatly limited by the high charge recombination rate at the host/guest interface.…”

Flexible Photocatalytic Paper with Cu2O and Ag Nanoparticle-Decorated ZnO Nanorods for Visible Light Photodegradation of Organic Dye

“…The NR and NP heterojunction interface facilitates charge separation and thus enhances photocatalysis. Reports of ZnO NRs decorated with various types of NPs (or alternatively named as nanocomposite) such as ZnSe [10], Ag 2 S [11], CdS [11–13], CuO [14], Cu 2 O [15, 16], ZnFe 2 O 4 [17], Ag [16, 18, 19], and Au [12, 20] have been abundant in the literature.…”

“…Therefore, simultaneous decoration with both narrow band gap semiconductor and noble metal NPs seems a rational approach to achieve high efficiency. Few works have been reported so far, and indeed, higher photodegradation efficiency has been achieved in comparison with single decoration [12, 16]. The advantages of simultaneous decoration are argued to be enhanced visible light absorption of the semiconductor NPs and faster electron transfer in the ternary nanocomposite, both attributed to the plasmonic effect of noble metal NPs [12].…”