Ultrathin Carbon Film Electrodes from Vacuum‐Carbonised Cellulose Nanofibril Composite

Abstract

A novel way to produce ultrathin transparent carbon layers on tin-doped indium oxide (ITO) substrates is developed. The ITO surface is coated with cellulose nanofibrils (from sisal) via layer-by-layer electrostatic binding with poly(diallyldimethylammonium chloride) or PDDAC acting as the binder. The cellulose nanofibril-PDDAC composite film is then vacuum-carbonised at 500 8C. The resulting carbon films are characterised by atomic force microscopy (AFM), small angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and Raman methods. Smooth carbon films with good adhesion to the ITO substrate are formed. The electrochemical characterisation of the carbon films is based on the oxidation of hydroquinone and the reduction of benzoquinone in aqueous phosphate buffer media. A modest effect of the cellulose nanofibril-PDDAC film on the rate of electron transfer is observed. The effect of the film on the rate of electron transfer after carbonisation is more dramatic. For a 40-layer cellulose nanofibril-PDDAC film after carbonisation a two-order of magnitude change in the rate of electron transfer occurs presumably due to a better interaction of the hydroquinone/benzoquinone system with the electrode surface.

Intrinsically Microporous Polymer Retains Porosity in Vacuum Thermolysis to Electroactive Heterocarbon

“…Vacuum carbonisation 1,2 offers a direct approach to the formation of porous carbon products 3,4,5 via conversion of organic precursor materials such as cellulose, 6,7 starches, 8,9 chitosan, 10,11 poly-acrylonitrile, 12,13 poly-pyridine, 14 graphene oxide, 15,16 or other types of carbon sources. 17,18 Charring may occur under mild conditions, but graphitisation only takes place at much higher temperatures (beyond 1000 o C) yielding more ordered and more electrically conducting forms of carbon.…”

Carbon Nanoparticle Surface Electrochemistry: High‐Density Covalent Immobilisation and Pore‐Reactivity of 9,10‐Anthraquinone

“…New types of nanocarbon materials such as nanotubes [5], nanoonions [6], graphene flakelets [7], nanodiamond [8], and hydrothermal [9] or pyrolytic [10] carbons are now widely investigated and employed as a substrate for surface modification and optimisation [11]. Methods for covalent surface attachment to carbon have been developed based, for example, on diazonium chemistry [12], Kolbe attachment [13], photografting of olefins [14], silane attachment [15], and "click-coupling" [16,17].…”

Feedback‐amplified electrochemical dual‐plate boron‐doped diamond microtrench detector for flow injection analysis

“…The oxidation of hydroquinone see Eq. is employed as a model redox system to explore the sensitivity of the BDD dual‐plate microtrench detector for a classical electrochemically irreversible (but chemically reversible) test system . …”