Development of a 3-electrode system for gas phase dynamic electrochemistry

The principles of potentiometry from liquid phase electrochemistry have already been applied to the gas phase by considering a flame as an ionised gaseous environment which can behave as a dilute electrolyte. This study focused on the design, construction and optimisation of a 3-electrode electrochemical cell for direct electron transfer in the gas phase. Three electrochemical cells were developed with the final design deemed satisfactory to conduct electrochemical measurements. Particular attention was given to the development of the reference electrode, which allows for stable voltage measurements. The reference electrodes analysed for their voltage stability and polarisability were metal wires, a dynamic type electrode and metal / metal oxide powders packed into ceramic supports. Through extensive studies, titanium wire (which forms a solid oxide layer once placed in the flame) was deemed to behave as a stable reference electrode. In conjunction with the electrode assembly and the titanium metal wire reference electrode, two metal salt clusters were individually introduced into the flame. The metal salt clusters were characterised by their reproducible electrochemical responses through cyclic voltammetry. Three negative peaks were observed when ammonium molybdate tetrahydrate was introduced into the flame. In contrast, four negative peaks were observed (at different voltage positions) when the metal salt cluster was replaced with ammonium metatungstate hydrate. The results suggest that electroreduction is indeed possible in the gas phase with reproducible Faradaic current responses being observed. The results are well supported by unambiguous correlation of the reduction potentials for peaks observed for the metal salt clusters to the vertical electron detachment energies obtained from photoelectron emission spectroscopy. The developed electrochemical cell and technique can be used to further characterise other chemical compounds

Information Asymmetry, Financialisation and Financial Access

This study investigates whether information sharing channels that are meant to reduce information asymmetry have led to an increase in financial access. The study employs a Generalised Method of Moments technique using data from 53 African countries during the period from 2004-2011 to examine this linkage. Information sharing channels are theoretically designed to promote the formal financial sector and discourage the informal financial sector. The study uses two information sharing channels: private credit bureaus and public credit registries. The study found that both information sharing channels have a positive and significant impact on financial access. The study also found that public credit registries complement the formal financial sector to promote financial access. The policy implications are discussed

Plasma electrochemistry: development of a reference electrode material for high temperature plasma.

This report describes the development of a high temperature reference electrode material for gas phase electrochemistry investigations. The electrode is constructed by careful assessment of different metal/metal oxide materials and operational stability in flame electrolyte medium. This will enable reliable dynamic electrochemistry investigations into redox reactions at the solid/gas interface, free of any solvent defined potential window restrictions