Copper electrodes, prepared by reduction of oxidized metallic copper have been reported to exhibit higher activity for the electrochemical reduction of CO2 and better selectivity towards C2 and C3 (C2+) products than metallic copper that has not been pre-oxidized. We report here an investigation of the effects of four different preparations of oxide-derived electrocatalysts on their activity and selectivity for CO2 reduction, with particular attention given to the selectivity to C2+ products. All catalysts were tested for CO2 reduction in 0.1 M KHCO3 and 0.1 M CsHCO3 at applied voltages in the range of -0.7 V to -1.0 V vs RHE. The best performing oxide-derived catalysts show up to ~70% selectivity to C2+ products and only ~3% selectivity to C1 products at -1.0 V vs RHE when CsHCO3 is used as the electrolyte. In contrast, the selectivity to C2+ products decreases to ~56% for the same catalysts tested in KHCO3. By studying all catalysts under identical conditions, the key factors affecting product selectivity could be discerned. These efforts reveal that the surface area of the oxide-derived layer is a critical parameter affecting selectivity. A high selectivity to C2+ products is attained at an overpotential of -1 V vs RHE by operating at a current density sufficiently high to achieve a moderately high pH near the catalyst surface but not so high as to cause a significant reduction in the local concentration of CO2. Based on recent theoretical studies, a high pH suppresses the formation of C1 relative to C2+ products. At the same time however, a high local CO2 concentration is necessary for the formation of C2+ products.3

, GG (2012), Polypyrrole coated nylon lycra fabric as stretchable electrode for supercapacitor applications, Electrochimica Acta, 68, Polypyrrole coated nylon lycra fabric as stretchable electrode for supercapacitor applications AbstractWearable electronics offer the combined advantages of both electronics and fabrics. Being an indispensable part of these electronics, lightweight, stretchable and wearable power sources are strongly demanded. Here we describe a daily-used nylon lycra fabric coated with polypyrrole as electrode for stretchable supercapacitors. Polypyrrole was synthesized on the fabric via a simple chemical polymerization process with ammonium persulfate (APS) as an oxidant and naphthalene-2,6-disulfonic acid disodium salt (Na 2 NDS) as a dopant. This material was characterized with FESEM, FTIR, tensile stress, and studied as a supercapacitor electrode in 1.0 M NaCl. This conductive textile could endure 1000 stretching cycles with 100% strain applied, and still retained its electrical conductivity and electrochemical properties. Interestingly, we also found that this material showed improved electrochemical properties when it was being stretched. ABSTRACTWearable electronics offer the combined advantages of both electronics and fabrics.

A polypyrrole/reduced graphene oxide (PPy/r‐GO) composite film is prepared by inducing electrochemical reduction of graphene oxide incorporated into PPy as the dopant. This film has a wrinkled surface morphology with a porous structure as revealed by scanning electron microscopy. Its porous structure is attributed to the physical nature of the GO sheets, providing a templating effect during PPy deposition. This PPy/r‐GO composite is characterized using in‐situ UV–visible spectroelectrochemistry as well as Raman and Fourier‐transform IR spectroscopy. The PPy/r‐GO material shows greatly improved electrochemical properties, i.e., a high rate capability and excellent cycling stability when used as a cathode material in a lithium ion battery. It also delivers a large reversible capacity when used as an anode material, and this is mainly attributed to the reduced graphene oxide (r‐GO) component.