Tunable Plasmon-Induced Charge Transport and Photon Absorption of Bimetallic Au–Ag Nanoparticles on ZnO Photoanode for Photoelectrochemical Enhancement under Visible Light

Abstract

Noble metal nanostructures have been widely explored as an effective method to increase photon absorption and charge separation in plasmonic photocatalysis. In this study, we integrated two different noble metals, gold (Au) and silver (Ag), into Au/Ag bimetallic nanoparticles (BNPs) via solid-state thermal dewetting to investigate the room-temperature electrical conductivity, visible light absorption, and its effect on photoelectrochemical (PEC) activity. The Au/Ag BNPs give rise to extended visible light absorption range, exhibiting localized surface plasmon resonance (LSPR) effect that lead to strong surface-enhanced Raman spectroscopy. X-ray photoelectron spectroscopy shows binding energy shift in Au/Ag BNPs, suggesting electron transfer from Ag to Au where charge transport behavior can be tailored. Kelvin probe force microscopy and conductive atomic force microscopy displayed a significantly enhanced electrical conduction in Au/Ag BNPs due to the lowered Schottky barrier height. When the Au/Ag BNPs are incorporated onto ZnO semiconductor photoanode, the photoactivity was improved with lower charge transport resistance compared to monometallic and pristine ZnO. This work delivers a general approach to understand the plasmon-induced charge interaction, hence the photochemistry of noble metal BNP/semiconductor photoanode by incorporating a controllable composition ratio, which is capable of exploiting the enhanced electrical conduction and LSPR effect for PEC water splitting.

Investigation of a Highly Sensitive Surface-Enhanced Raman Scattering Substrate Formed by a Three-Dimensional/Two-Dimensional Graphene/Germanium Heterostructure

“…For accurate probing of local electronic transport properties in the heterojunction, conductive atomic force microscopy (CAFM) offers spatial mapping of conductance at a constant bias voltage in bulk. Simultaneous imaging of the topography and current map facilitates rapid and proper identification of charge transport properties in various samples and the contribution of local regions of the sample on the whole . The contact mode topographical image and corresponding current map (CAFM substrate bias of +0.2 V) of the 3D-graphene/AC surface are depicted in panels a and b of Figure , respectively, and the relevant images of the 3D/2D-graphene are shown in panels d and e of Figure .…”

“…Simultaneous imaging of the topography and current map facilitates rapid and proper identification of charge transport properties in various samples and the contribution of local regions of the sample on the whole. 32 The contact mode topographical image and corresponding current map (CAFM substrate bias of +0.2 V) of the 3Dgraphene/AC surface are depicted in panels a and b of Figure 2, respectively, and the relevant images of the 3D/2D-graphene are shown in panels d and e of Figure 2. The low current area (red area) corresponding to the gap is observed on the entire surface of the 3D-graphene film, which is attributed to the less sharp shape of the probe tip and cannot penetrate within the narrow spaces between the graphene sheets, resulting in the loose electrical tip−graphene contact.…”

Enhanced Performances of n-ZnO Nanowires/p-Si Heterojunctioned Pyroelectric Near–Infrared Photodetectors via the Plasmonic Effect

“…Through the annealing process, the deposited Au film first produces cracks, and then the cracks propagate around to form voids. Finally, with the growth of voids, the film is transformed into Au NP-coated ZnO NWs, 44 which is shown in Figure 1c. Figure 1d shows that the particle size of Au NPs is about 10 nm by the Gaussian fitting of the scientific counting method and SEM data.…”

Extraterrestrial artificial photosynthetic materials for in-situ resource utilization

“…Therefore, photoanode materials with high activity and stability are indispensable in improving the energy conversion efficiency of PEC systems for EAP. Numerous n-type semiconductors have been exploited and investigated, including n-type silicon [ 66 ], oxides [ 61 – 64 ], nitrides [ 103 ] and sulfides [ 104 ], as photoanodes for O 2 production. In addition, finely dispersed cocatalyst nanoparticles (e.g.…”