Direct borohydride fuel cells

The recent, rapid progress in the development of direct borohydride fuel cells is reviewed. Electrochemical reactions are considered together with the importance of operating parameters on cell performance. The advances in technology necessary for a widespread testing and more application of borohydride fuel cells are highlighted. A comparison of borohydride and methanol fuel cells shows that both system exhibit similar cell voltages, current and power densities despite that methanol cells operate at higher temperatures. The results are encouraging although more research is necessary, particularly in the synthesis of new electrocatalysts for borohydride oxidation

A direct borohydride–peroxide fuel cell using a Pd/Ir alloy coated microfibrous carbon cathode

A direct borohydride fuel cell with a Pd/Ir catalysed microfibrous carbon cathode and a gold-catalysed microporous carbon cloth anode is reported. The fuel and oxidant were NaBH4 and H2O2, at concentrations within the range of 0.1–2.0 mol dm-3 and 0.05–0.45 mol dm-3, respectively. Different combinations of these reactants were examined at 10, 25 and 42 oC. At constant current density between 0 and 113 mA cm-2, the Pd/Ir coated microfibrous carbon electrode proved more active for the reduction of peroxide ion than a platinised-carbon one. The maximum power density achieved was 78mWcm2 at a currentdensity of 71 mA cm-2 and a cell voltage of 1.09 V

A direct borohydride – acid peroxide fuel cell

A fuel cell operating with aqueous sodium borohydride and hydrogen peroxide streams, with one, two and four cells (electrode area 64, 128 and 256 cm2) connected in a bipolar mode in a filterpress flow cell is reported. The oxidation of borohydride ion was carried out on Au/C particles supported on a carbon felt electrode while the reduction of hydrogen peroxide was carried out on carbon supported Pt on a carbon paper substrate. Comparable cell potentials and power densities to direct borohydride fuel cells reported in the literature were obtained. The challenges to further development includes: increasing the low current density and avoid decomposition of borohydride and peroxide ions. The maximum power obtained at 20oC for one, two and four cell stacks was 2.2, 3.2 and 9.6 W (34.4, 25 and 37.5 mW cm-2 respectively) with cell voltages of 1.06, 0.81 and 3.2 V at current densities of 32, 16 and 12 mA cm-2, respectively

Biofuel cells and their development

A biofuel cell electrochemical system based on the oxidation of glucose by glucose oxidase has been developed. The glucose oxidase was immobilised at the electrode surface by a cast Nafion polymer membrane neutralised and modified by tetrabutylammonium bromide to stabilise the membrane. Electrochemical communication with the electrode was established with ferrocene derivatives in solution or co-cast with the Nafion. The individual and combined properties of the components of the system were investigated to select the best components to create a biofuel cell.After establishing a functioning biofuel cell a scale-up procedure was followed in which the chemical system was transferred to higher area electrodes. A laboratory prototype biofuel cell was designed and used to test larger 3-d electrode materials. Before use as an electrochemical reactor the flow properties of the test cell and electrodes were investigated by pulse injections of concentrated buffer tracked with an inline conductivity probe.The biofuel cell generated a steady state power density of up to 50 ?W cm-2 superficial area at a graphite plate electrode or 6 ?W cm-2 (actual surface basis) at a reticulated vitreous carbon electrode. The test cell demonstrated high cell potentials for a biofuel cell based on a single enzyme electrode and gave a stable output for several days

The role of laboratory investigation in the diagnosis and management of patients with suspected herpes simplex encephalitis: a consensus report. The EU Concerted Action on Virus Meningitis and Encephalitis.

As effective therapies for the treatment of herpes simplex encephalitis (HSE) have become available, the virology laboratory has acquired a role of primary importance in the early diagnosis and clinical management of this condition. Several studies have shown that the polymerase chain reaction (PCR) of CSF for the detection of herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) DNA provides a reliable method for determining an aetiological diagnosis of HSE. The use of PCR in combination with the detection of a specific intrathecal antibody response to HSV currently represents the most reliable strategy for the diagnosis and monitoring of the treatment of adult patients with HSE. The use of these techniques has also led to the identification of atypical presentations of HSV infections of the nervous system and permits the investigation of patients who develop a relapse of encephalitic illness after an initial episode of HSE. A strategy for the optimal use of the investigative laboratory in the diagnosis of HSE and subsequent management decisions is described