Surface plasmon enhanced ethylene glycol electrooxidation based on hollow platinum-silver nanodendrites structures.

The surface plasmon resonance (SPR) effect on noble metals to convert solar energy into chemical has attracted a lot of interest. However, the lack of highly efficient photocatalysts is still the forbidden obstacle as well as their large-scale development. Therefore, we focus on plasmon resonance enhanced electrocatalytic oxidation of liquid fuel employing photocatalysts to develop unique hollow platinum-silver (Pt-Ag) nanocrystals. The hollow Pt-Ag is formed of nanodendrites (Pt1-Ag1) which display a great enhancement in catalytic activity towards ethylene glycol oxidation with the mass and specific activity found to be: 7045.2?mA/mg and 14.1?mA/cm2, respectively. This is due to: the SPR effect, efficient electronic distribution and synergistic properties, together with the unique hollow dendritic nanostructures. Impressively, the SPR effect also induces the optimum Pt-Ag nanocatalsyst under visible light irradiation conditions to display 1.7-fold enhancements in catalytic activity compared to that under dark conditions. In addition, 6.2 and 7.0-fold enhancements were obtained when the optimized Pt-Ag was employed as photoelectrocatalyst compared to the commercial Pt/C. Therefore, we present a unique catalyst which produces a high catalytic activity and long-term stability compared to those previously reported. More importantly, we also introduce a promising approach towards the designing of a plasmonic metal nanocatalyst with ideal nanostructures for liquid fuel oxidations

Sophisticated construction of binary PdPb alloy nanocubes as robust electrocatalysts toward ethylene glycol and glycerol oxidation.

The design of nanocatalysts by controlling pore size and particle characteristics is crucial to enhance the selectivity and activity of the catalysts. Thus, we have successfully demonstrated the synthesis of binary PdPb alloy nanocubes (PdPb NCs) by controlling pore size and particle characteristics. In addition, the as-obtained binary PdPb NCs exhibited superior electrocatalytic activity of 4.06 A mg-1 and 16.8 mA cm-2 towards ethylene glycol oxidation reaction (EGOR) and 2.22 A mg-1 and 9.2 mA cm-2 towards glycerol oxidation reaction (GOR) when compared to the commercial Pd/C. These astonishing characteristics are attributed to the attractive nanocube structures as well as the large number of exposed active areas. Furthermore, the bifunctional effects originated from Pd and Pb interactions help to display high endurance with less activity decay after 500 cycles, showing a great potential in fuel cells applications

WS2 as an Effective Noble-Metal Free Cocatalyst Modified TiSi2 for Enhanced Photocatalytic Hydrogen Evolution under Visible Light Irradiation

A noble-metal free photocatalyst consisting of WS2 and TiSi2 being used for hydrogen evolution under visible light irradiation, has been successfully prepared by in-situ formation of WS2 on the surface of TiSi2 in a thermal reaction. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results demonstrate that WS2 moiety has been successfully deposited on the surface of TiSi2 and some kind of chemical bonds, such as Ti-S-W and Si-S-W, might have formed on the interface of the TiSi2 and WS2 components. Optical and photoelectrochemical investigations reveal that WS2/TiSi2 composite possesses lower hydrogen evolution potential and enhanced photogenerated charge separation and transfer efficiency. Under 6 h of visible light (λ > 420 nm) irradiation, the total amount of hydrogen evolved from the optimal WS2/TiSi2 catalyst is 596.4 μmol·g−1, which is around 1.5 times higher than that of pure TiSi2 under the same reaction conditions. This study shows a paradigm of developing the effective, scalable and inexpensive system for photocatalytic hydrogen generation

One-Step Synthesis of MoS₂/TiSi₂ via an In Situ Photo-Assisted Reduction Method for Enhanced Photocatalytic H₂ Evolution under Simulated Sunlight Illumination

A new MoS2/TiSi2 complex catalyst was designed and synthesized by a simple one-step in situ photo-assisted reduction procedure. The structural and morphological properties of the composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and ultraviolet-visible diffused reflectance spectroscopy (UV-vis DRS), which proved the formation of MoS2/TiSi2. MoS2/TiSi2 with optimized composition showed obviously enhanced photocatalytic activity and superior durability for water reduction to produce H2. The H2 generation rate over the MoS2/TiSi2 photocatalyst containing 3 wt % MoS2 reached 214.1 μmol·h−1·g−1 under visible light irradiation, which was ca. 5.6 times that of the pristine TiSi2. The improved photocatalytic activity of MoS2/TiSi2 could be related to the broad response spectrum, large visible light absorption, and synergies among MoS2 and TiSi2 that enhance photoexcited charge transfer and separation

Characterization and Thermoelectric Behavior of Super-growth Carbon Nanotube Films Co-loaded with ZnO and Ag Colloids

The fabrication of low-temperature waste heat power conversion modules will require the development of thermoelectric materials based on mass-produced nanotubes such as super-growth carbon nanotubes (SGCNTs), rather than high-quality nanotubes generated on the laboratory scale. In this work, SGCNT films co-loaded with colloidal ZnO (which has a high Seebeck coefficient) and Ag (which enhances electrical conductivity) were prepared to optimize both carrier concentration and mobility. The resulting carbon-based hybrid films were found to have a p-type power factor of 100.4 µW m−1 K−2 at 383 K, which represented one of the highest values yet reported for a SGCNT system

WS2 as an Effective Noble-Metal Free Cocatalyst Modified TiSi2 for Enhanced Photocatalytic Hydrogen Evolution under Visible Light Irradiation

A noble-metal free photocatalyst consisting of WS2 and TiSi2 being used for hydrogen evolution under visible light irradiation, has been successfully prepared by in-situ formation of WS2 on the surface of TiSi2 in a thermal reaction. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results demonstrate that WS2 moiety has been successfully deposited on the surface of TiSi2 and some kind of chemical bonds, such as Ti-S-W and Si-S-W, might have formed on the interface of the TiSi2 and WS2 components. Optical and photoelectrochemical investigations reveal that WS2/TiSi2 composite possesses lower hydrogen evolution potential and enhanced photogenerated charge separation and transfer efficiency. Under 6 h of visible light (λ > 420 nm) irradiation, the total amount of hydrogen evolved from the optimal WS2/TiSi2 catalyst is 596.4 μmol·g−1, which is around 1.5 times higher than that of pure TiSi2 under the same reaction conditions. This study shows a paradigm of developing the effective, scalable and inexpensive system for photocatalytic hydrogen generation

Hydrothermal Method Using DMF as a Reducing Agent for the Fabrication of PdAg Nanochain Catalysts towards Ethanol Electrooxidation

In this article, we developed a facile one-step hydrothermal method using dimethyl formamide (DMF) as a reducing agent for the fabrication of PdAg catalyst. The scanning electron microscope (SEM) and transmission electron microscopy (TEM) images have shown that the as-synthesized PdAg catalyst had a nanochain structure. The energy-dispersive X-ray analyzer (EDX) spectrum presented the actual molar ratio of Pd and Ag in the PdAg alloy. Traditional electrochemical measurements, such as cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectrometry (EIS), were performed using a CHI 760D electrochemical analyzer to characterize the electrochemical properties of the as-synthesized catalyst. The results have shown that the PdAg catalyst with a nanochain structure displays higher catalytic activity and stability than pure Pd and commercial Pd/C catalysts

Newly Designed Ternary Metallic PtPdBi Hollow Catalyst with High Performance for Methanol and Ethanol Oxidation

This paper reported the fabrication of ternary metallic PtPdBi hollow nanocatalyst through a facile, one-pot, wet-chemical method by adopting sodium borohydride and polyvinylpyrrolidone as reducing agent and surfactant directing agent, respectively. The hollow structure offers novel morphology and large surface areas, which are conducive to enhancing the electrocatalytic activity. The electrocatalytic properties of hollow PtPdBi nanocatalyst were investigated systematically in alkaline media through cyclic voltammetry and the as-prepared PtPdBi nanocatalyst displays greatly enhanced electrocatalytic activities towards methanol and ethanol oxidation. The calculated mass activities of PtPdBi electrocatalyst are 2.133 A mgPtPd−1 for methanol oxidation reaction and 5.256 A mgPtPd−1 for ethanol oxidation reaction, which are much better than that of commercial Pt/C and commercial Pd/C. The as-prepared hollow nanocatalyst may be a potential promising electrocatalyst in fuel cells and also may be extended to the applications of other desirable functions

The Enhanced Photo-Electrochemical Detection of Uric Acid on Au Nanoparticles Modified Glassy Carbon Electrode

Abstract In this work, a sensitive and novel method for determining uric acid (UA) has been developed, in which the glassy carbon electrode (GCE) was modified with electrodeposition Au nanoparticles and used to monitor the concentration of UA with the assistant of visible light illumination. The morphology of the Au nanoparticles deposited on GCE surface were characterized by scanning electron microscope (SEM) and the nanoparticles were found to be well-dispersed spheres with the average diameter approaching 26.1 nm. A series of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements have revealed that the introduction of visible light can greatly enhance both the strength and stability of response current due to the surface plasmon resonance (SPR). Specifically, the DPV showed a linear relationship between peak current and UA concentration in the range of 2.8 to 57.5 μM with the equation of I pa (μA) = 0.0121c UA (μM) + 0.3122 (R 2 = 0.9987). Herein, the visible light illuminated Au/GCE possesses a potential to be a sensitive electrochemical sensor in the future