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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.

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.

Picric acid (PA) is a severe environmental and security risk due to its unstab e, toxic, and explosive properties. It is also challenging to detect in trace amounts and in situ because of its highly acidic and anionic character. Here, we assess sensing of PA under nonlaboratory conditions using surface-enhanced Raman scattering (SERS) silver nanopillar substrates and handheld Raman spectroscopy equipment. The advancing elasto-capillarity effects are explained by molecular dynamics simulations. We obtain a SERS PA detection limit on the order of 20 ppt, corresponding attomole amounts, which together with the simple analysis methodology demonstrates that the presented approach is highly competitive for ultrasensitive analysis in the field.

Penta-graphene is the name given to a novel puckered monolayer of carbon atoms tightly packed into an inerratic pentagonal network, theoretically, which exhibits excellent thermal and mechanical stability and can be rolled into penta-graphene nanotubes (PGNTs). Herein, we perform the first simulation study of mechanical properties of PGNTs under uniaxial tension. In addition to comparable mechanical properties with that of carbon nanotubes (CNT), it is found that PGNTs possess promising extensibility with typical plastic behavior due to the irreversible pentagon-to-polygon structural transformation. The plastic characteristic of PGNTs is inherent with strain-rate and tube-diameter independences. Moreover, within ultimate temperature (T < 1100 K), tensile deformed PGNTs manifest similar phase transition with an approximate transition ratio from pentagon to hexagon. The intrinsic insight provides a fundamental understanding of mechanic properties of PGNTs, which should open up a novel perspective for design of plastic carbon-based nanomaterials.

Picric acid (PA) is a severe environmental and security risk due to its unstable, toxic, and explosive properties. It is also challenging to detect in trace amounts and in situ because of its highly acidic and anionic character. Here, we assess sensing of PA under nonlaboratory conditions using surface-enhanced Raman scattering (SERS) silver nanopillar substrates and hand-held Raman spectroscopy equipment. The advancing elasto-capillarity effects are explained by molecular dynamics simulations. We obtain a SERS PA detection limit on the order of 20 ppt, corresponding attomole amounts, which together with the simple analysis methodology demonstrates that the presented approach is highly competitive for ultrasensitive analysis in the field.