ABSTRACT
For the oxidation of water to dioxygen, oxide-covered ruthenium metal is known as the most efficient catalyst, however, with limited stability. Herein, we present a strategy for incorporating a Ru/C composite onto a novel nanoporous electrode surface with low noble metal loading and improved stability. The Ru/C is coated on the pore walls of anodic alumina templates in a one-step laser-induced deposition method from Ru3(CO)12 solutions. Scanning electron microscopy proves the presence of a continuous Ru/C layer along the inner pore walls. The amorphous material consists of metallic Ru incorporated in a carbonaceous C matrix as shown by X-ray diffraction combined with Raman and X-ray photoelectron spectroscopies. These porous electrodes reveal enhanced stability during water oxidation as compared to planar samples at pH 4. Finally, their electrocatalytic performance depends on the geometric parameters and is optimized with 13 µm pore length, which yields 2.6 mA cm-2, or 49 A g-1, at η = 0.20 V.
ABSTRACT
Invited for this month's cover are collaborating researchers from the DM3 group at the European Membrane Institute of Montpellier, France. The cover picture shows an artistic view of the bioelectrochemical production of sustainable electricity. Laccase enzymes immobilized on aligned electrospun carbon fibers can efficiently reduce dissolved oxygen, and be used in the cathode compartment of an electrical biogenerator. Read the full text of the article at 10.1002/cplu.201402324.
ABSTRACT
Electrospun carbon fiber electrodes showing high performance for bio-electrochemical applications were developed. Easy to handle and manipulate aligned and unaligned carbon fibers with a mean diameter of (330±50)â nm were synthesized through an electrospinning technique. Electrical resistivity measurements, which are a challenge that has not been much explored in the case of fibrous materials, were realized through two different techniques, and a study of contact resistances between electrical clips and the carbon fibers was performed. To target the creation of a bioelectrode, carbon fibers were characterized electrochemically by cyclic voltammetry. After being modified with the enzyme laccase, its response to oxygen electroreduction was studied. Aligned fibers present a cathodic current that is 30 % higher than that of randomly distributed fibers. Overall, the results show that aligned fibers are more appropriate for bio-electrochemical applications when exploiting anisotropic spatial organization.
