Flexible Supercapacitor Sheets Based on Hybrid Nanocomposite Materials

Nanomaterials with quasi-zero, one and two dimensionalities, including silicon nanoparticles, carbon nanotubes, titanium oxide particles and graphene flakes, have been incorporated into the conducting polymer polyaniline to form nanocomposite materials for making flexible supercapacitor sheets. Characterization of the capacitor sheets showed that the inclusion of the nanomaterials in polyaniline has significantly improved the energy and power capabilities of the capacitor. In particular, a specific capacitance of 477.1 F/g has been obtained. The important properties of carbon nanotubes of improving the charge storage and reducing the resistance of the nanocomposite material and hence to enhance the power capability of the capacitor sheets have been studied. Stacks of capacitor sheets have been used to power a LED lamp to demonstrate the potential of the nanocomposite-based capacitor sheet in illumination applications

Flexible Supercapacitor Sheets Based on Hybrid Nanocomposite Materials

Nanomaterials with quasi-zero, one and two dimensionalities, including silicon nanoparticles, carbon nanotubes, titanium oxide particles and graphene flakes, have been incorporated into the conducting polymer polyaniline to form nanocomposite materials for making flexible supercapacitor sheets. Characterization of the capacitor sheets showed that the inclusion of the nanomaterials in polyaniline has significantly improved the energy and power capabilities of the capacitor. In particular, a specific capacitance of 477.1 F/g has been obtained. The important properties of carbon nanotubes of improving the charge storage and reducing the resistance of the nanocomposite material and hence to enhance the power capability of the capacitor sheets have been studied. Stacks of capacitor sheets have been used to power a LED lamp to demonstrate the potential of the nanocomposite-based capacitor sheet in illumination applications

A Silicon Nanoparticle-based Polymeric Nano-composite Material for Glucose Sensing

A novel non-enzyme glucose sensing material has been prepared by incorporating ultrasmall (1–3 nm) silicon nanoparticles in polyaniline, a conducting polymer, as a nano-composite material (NCM). When deposited on electrodes, the composite material with three-dimensional loading of the nanoparticles showed a significantly enhanced amperometric response to glucose, compared to the nanoparticles deposited on bare electrodes and electrodes immobilized with the enzyme, glucose oxidase. The linear range of the glucose response of NCM electrodes covered both the hypo- and hyper-glycaemic glucose levels. The sensitivity of the NCM electrodes was 2.5 μA cm−2 mM−1. The NCM electrodes’ selectivity for glucose against interfering agents was achieved by covering the composite material with a Nafion membrane. The glucose response of Nafion–NCM electrodes was characterized with single 1 μl drops of glucose-solution, showing a sensitivity of 2.2 μA cm−2 mM−1. The NCM electrode’s long-term in vitro glucose response appeared to be reasonably stable over a period of 40 days

A Hybrid Biofuel Cell Based on Electrooxidation of Glucose Using Ultra-Small Silicon Nanoparticles

The ultra-small silicon nanoparticle was shown to be an electrocatalyst for the electrooxidation of glucose. The oxidation appeared to be a first order reaction which involves the transfer of 1 electron. The oxidation potential showed a low onset of −0.4V vs. Ag/AgCl (−0.62V vs. RHE). The particle was used as the anode catalyst of a prototype hybrid biofuel cell, which operated on glucose and hydrogen peroxide. The output power of the hybrid cell showed a dependence on the enzymes used as the cathode catalyst. The power density was optimized to 3.7μW/cm2 when horseradish peroxidase was replaced by microperoxidase-11 (MP-11). Comparing the output power of the hybrid cell to that of a biofuel cell indicates enhanced cell performance due to the fast reaction kinetics of the particle. The long-term stability of the hybrid cell was characterized by monitoring the cell voltage for 5 days. It appeared to that the robustness of the silicon particle resulted in more cell stability compared to the long-term performance of a biofuel cell

A Hybrid Biofuel Cell Based on Electrooxidation of Glucose Using Ultra-Small Silicon Nanoparticles

The ultra-small silicon nanoparticle was shown to be an electrocatalyst for the electrooxidation of glucose. The oxidation appeared to be a first order reaction which involves the transfer of 1 electron. The oxidation potential showed a low onset of −0.4V vs. Ag/AgCl (−0.62V vs. RHE). The particle was used as the anode catalyst of a prototype hybrid biofuel cell, which operated on glucose and hydrogen peroxide. The output power of the hybrid cell showed a dependence on the enzymes used as the cathode catalyst. The power density was optimized to 3.7μW/cm2 when horseradish peroxidase was replaced by microperoxidase-11 (MP-11). Comparing the output power of the hybrid cell to that of a biofuel cell indicates enhanced cell performance due to the fast reaction kinetics of the particle. The long-term stability of the hybrid cell was characterized by monitoring the cell voltage for 5 days. It appeared to that the robustness of the silicon particle resulted in more cell stability compared to the long-term performance of a biofuel cell

Fluorescent Si Nanoparticle-Based Electrode for Sensing Biomedical Substances

We have been studying the miniaturization of silicon crystals and the transition from the solid state to the atomistic state. We demonstrated the existence of “sweet spots” in cluster size in the range 1–3nm that have enhanced chemical, structural, and photo stability. The particles are produced by an electrochemical etching process as dispersion in liquid, and they are reconstituted in films, patterns, alloys, or spread on chips to produce super chips. Unlike bulk, these Si nanoparticle configurations have a spectacular ability to glow in distinct RGB colors. In this paper we describe an electrode sensor built by decorating metal or heavily doped silicon electrode with nanoparticles. We demonstrated amperometric response of the electrode to glucose and compared the response to that of heavily doped silicon wafer decorated with GOx. The all silicon electrode shows improved sensitivity, selectivity and stability. Light induced modulation of the response allows phase sensitive detection. The device is suitable for miniaturization, which may enable in vivo use

Worrying about climate change

The paper discusses the impact of climate change on ten sectors: water, water desalination, energy, renewable energy supply, health, society, agriculture, economy, industry, and built environment. Each of the sectors has unique characteristics that require special consideration. Planning for climate change adaptation is among the most complex challenges cities are facing today. Climatic alterations put a strain on 1) energy needs for cooling/heating and release of anthropogenic heat, 2) mortality and morbidity due to air pollution and air turbidity, 3) productivity and wellbeing, and 4) accessibility to public spaces and social prosperity. There are many innovate ideas and proposals suggested in order to minimize the impact of climate change, but no simple solution exists because of the interdependence and fast-moving technological solutions, and the role of the policy makers in setting targets and providing finance for solutions