In Situ Charge Transfer at the Ag@ZnO Photoelectrochemical Interface toward the High Photocatalytic Performance of H₂ Evolution and RhB Degradation

Abstract

Designing an efficient hybrid structure photocatalyst for photocatalytic decomposition and hydrogen (H2) evolution has been considered a great choice to develop renewable technologies for clean energy production and environmental remediation. Enhanced charge transfer (CT) based on the interaction between a noble metal and a semiconductor is a crucial factor influencing the movement of photogenerated electron–hole pairs. Herein, we focus on the recent advances related to plasmon-enhanced noble metals and the semiconductor nature to drive the photocatalytic H2 production and photodegradation of the organic dye rhodamine B (RhB) under UV and visible light irradiation. Specifically, the combination of concerted catalysis and green nanoengineering strategies to design ZnO-based composite photocatalysts and their decoration with metallic Ag have been realized by the radio frequency (RF) sputtering technique at room temperature. This simultaneity enhances the interface coupling between Ag and ZnO and reduces the energy threshold. The creation of charge transfer in the heterojunction and Schottky barrier changes the photoelectronic properties of the as-synthesized Al-doped ZnO (AZO); afterward, these effects promote the migration, transportation, and separation of photoinduced charge carriers and enhance the light-harvesting efficiency. As a result, the as-synthesized AZO-20 hybrid nanostructure exhibits a photocurrent density of 2.5 mA/cm2 vs Ag/AgCl, which is improved by almost 12 times compared with that of bare ZnO (0.2 mA/cm2). The hydrogen evolution rates of AZO-20 were ∼38 and ∼24 μmol/h under UV and visible light exposure, which are almost five- and tenfold higher than those of pristine ZnO, respectively. Additionally, the RhB degradation efficacies of the obtained AZO-20 were greater than almost 97 and 82% under UV and visible light illumination, respectively. The achieved apparent rate constant for the photocatalytic RhB decomposition was 0.014 min–1, indicating that it is 14-fold than that in pristine ZnO (0.001 min–1). Heterostructure AZO photocatalysts possess excellent practical stability in the water-splitting reaction and photocatalytic RhB decomposition, posing as promising candidates in practical works for pollution and energy challenges.

One-pot, ligand-free, room-temperature synthesis of Au/Pd/ZnO nanoclusters with ultra-low noble metal loading and synergistically improved photocatalytic performances

“…[28][29][30] Hence, the combination of ZnO with noble metals to form noble metal/semiconductor hybrid nanostructures has been proposed as an efficient way to increase photocatalytic efficiency. [31][32][33] Bimetallic (such as AuPd, 24,[28][29][30]34,35,42 AuPt, [36][37][38][39] AgPd 40,41 ) NPs couple with semiconductors have better performance in comparison with monometallic NPs due to the synergistic effects. In particular, AuPd NPs have been proved to promote the photochemical activity signicantly.…”

Ag-grafted on ZnO nanorod arrays using UV-assisted irradiation for enhanced SERS behavior in CV detection

“…Therefore, it is vital to develop SERS semiconductor substrates with high sensitivity, low cost, uniformity, and reproducibility. Compared with other metal oxide materials, Zinc oxide (ZnO) has been intensively carried out for SERS because of its enrichment, economical fabrication, nontoxicity, and photochemical stability 13,14 . Plasmonic nanoparticles are deposited Cite this article : Trang T N Q, Huong L T C, Duong T, Thu V T H. Ag-grafted on ZnO nanorod arrays using UV-assisted irradiation for enhanced SERS behavior in CV detection.…”

Spectral characteristics upon harvesting plasmonic hot electrons at the Ag/ZnO heteromicrostructures

“…23 Therefore, heterostructures comprising of semiconducting ZnO and plasmonic Ag with well-defined morphologies have attracted significant interest owing to their potential for providing new opportunities for optimising, tuning and/or enhancing the optical properties, electronic structure, electrical characteristics, and light-induced charge separation effects. [24][25][26] These plasmonic/dielectric heterostructures have gained considerable attention for studying their absorption spectral features, 27 photoluminescence, 28 Raman scattering, 29 second harmonic generation, 30 electrical conductivity, 31,32 and photocatalytic 33 and biological activity. 34,35 There have been extensive studies on the synthesis, characterization and applications of heteronanostructures; however, hardly any attention has been paid to the investigation of these aspects in microstructures.…”