Nanoscale Au-In alloy-oxide core-shell particles as electrocatalysts for efficient hydroquinone detection

The presence of hydroquinone (HQ), a phenol ubiquitous in nature and widely used in industry, needs to be monitored because of its toxicity to the environment. Here we demonstrate efficient detection of HQ using simple, fast, and noninvasive electrochemical measurements on indium tin oxide (ITO) electrodes modified with nanoparticles comprising bimetallic Au–In cores and mixed Au–In oxide shells. Whereas bare ITO electrodes show very low activity for the detection of HQ, their modification with Au–In core–shell nanoparticles induces a pronounced shift of the oxidation peak to lower potentials, i.e., facilitated oxidation. The response of the different electrodes was correlated with the initial composition of the bimetallic nanoparticle cores, which in turn determined the amount of Au and In stabilized on the surface of the amorphous Au–In oxide shells available for the electrochemical reaction. While adding core–shell nanostructures with different compositions of the alloy core facilitates the electrocatalytic (reduction-) oxidation of HQ, the activity is highest for particles with AuIn cores (i.e., a Au:In ratio of 1). This optimal system is found to follow a single pathway, the two-electron oxidation of the quinone–hydroquinone couple, which gives rise to high oxidation peaks and is most effective in facilitating the electrode-to-analyte charge transfer and thus detection. The limits of detection (LOD) decreased when increasing the amount of Au exposed on the surface of the amorphous Au–In oxide shells. The LODs were in the range of 10–5–10–6 M and were lower than those obtained using bulk Au.2022-07-72022-07-07Research carried out in part at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-SC0012704. EB- 14, University of Valladolid (PIF-UVa) Ministerio de Economía, Industria y Competitividad – FEDER (Grant CICYT AGL2012-335

Impact of nano-silicon fuel additive on combustion, performance and emission of a twin cylinder CI engine

Combustion characteristics of a fuel defines its performance and emission characteristics. Enhancement of combustion characteristics is feasible by improvisation of fuel properties. Fuel additives were used for varying fuel properties. The evolution of ‘nano-concept’ develops countless applications in the existing technologies. In this experiment silicon nanoparticles were synthesized by ball milling micron sized silicon particles for 45 hours. The elemental and structural characterizations for the additive material were carried out by EDS, SEM and TEM analysis. Silicon nano additive was mixed in three different weight proportions with diesel to prepare the test fuels. The fuel properties variation with the addition of nano additive were studied. Engine testing was carried out at constant 1200 rpm speed and varying load conditions. Diesel fuel added with 0.5 wt% Si nanoadditive (Si 0.5) showed maximum load carrying ability among the different test fuels. In comparison with diesel at 1200 rpm and 100% load condition, an increase in torque of 5.91% was observed and BTE was increased by 8.93% with a decrease in NOx emission by 27.3%. Variation in the performance and emission characteristics of the fuels were the results of change in heat release rate and combustion timing with the addition of nano additives which could be studied from the combustion characteristic curves

Impact of nano-silicon fuel additive on combustion, performance and emission of a twin cylinder CI engine

Combustion characteristics of a fuel defines its performance and emission characteristics. Enhancement of combustion characteristics is feasible by improvisation of fuel properties. Fuel additives were used for varying fuel properties. The evolution of ‘nano-concept’ develops countless applications in the existing technologies. In this experiment silicon nanoparticles were synthesized by ball milling micron sized silicon particles for 45 hours. The elemental and structural characterizations for the additive material were carried out by EDS, SEM and TEM analysis. Silicon nano additive was mixed in three different weight proportions with diesel to prepare the test fuels. The fuel properties variation with the addition of nano additive were studied. Engine testing was carried out at constant 1200 rpm speed and varying load conditions. Diesel fuel added with 0.5 wt% Si nanoadditive (Si 0.5) showed maximum load carrying ability among the different test fuels. In comparison with diesel at 1200 rpm and 100% load condition, an increase in torque of 5.91% was observed and BTE was increased by 8.93% with a decrease in NOx emission by 27.3%. Variation in the performance and emission characteristics of the fuels were the results of change in heat release rate and combustion timing with the addition of nano additives which could be studied from the combustion characteristic curves

Synthesis, Hammett spectral correlation and evaluation of antimicrobial activities of some substituted styryl 4'-piperidinophenyl ketones

1131-1143A series containing twelve substituted 4'-piperidinophenyl chalcones have been synthesized from crossed-aldol condensation between 4-piperidionphenyl methyl ketone and substituted benzaldehydes using solid Cu2+/Zeolite catalyzed microwave assisted method. The structures of chalcones have been characterized by their physical constants, analytical and spectral data. The observed spectral frequencies have been correlated with Hammett substituents, F and R parameters using both single and multi-regression analyses. All the substituted 4'-piperidinophenyl chalcones have been tested for antimicrobial activities using disc diffusion method

Assessment of substituent effects and antimicrobial activities of some 2ʹ,5ʹ-dimethyl phenyl chalcones

ABSTRACT Some 2ʹ,5ʹ-dimethyl phenyl chalcones have been synthesized by Crossed-Aldol condensation between 2,5-dimethyl acetophenone and various substituted benzaldehydes using catalytic amount of sodium hydroxide and ethanol. The yields of the chalcones are more than 93 %. The purities of these chalcones have been checked by their physical constants, UV, IR, NMR and MASS spectral data. The spectral data of these chalcones have been correlated with Hammett sigma constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effects of substituents on the spectral group frequencies have been discussed. The anti-microbial activities of these chalcones have been evaluated using Bauer-Kirby method