Département de chimie moléculaire

This paper details the electrochem. investigation of a deuteroporphyrin dimethylester (DPDE) rhodium(III) ((DPDE)RhIII) complex, immobilized within a MWCNT/Nafion electrode, and its integration into a mol. catalysis-based glucose fuel cell. The domains of present (DPDE)RhI, (DPDE)Rh-H, (DPDE)RhII, and (DPDE)RhIII were characterized by surface electrochem. performed at a broad pH range. The Pourbaix diagrams (plots of E1/2 vs pH) support the stability of (DPDE)RhII at intermediate pH and the predominance of the two-electron redox system (DPDE)RhI/(DPDE)RhIII at both low and high pH. This two-electron system is esp. involved in the electrocatalytic oxidn. of alcs. and was applied to the glucose oxidn. The catalytic oxidn. mechanism exhibits an oxidative deactivation coupled with a reductive reactivation mechanism, which has previously been obsd. for redox enzymes but not yet for a metal-based mol. catalyst. The MWCNT/(DPDE)RhIII electrode was finally integrated in a novel design of an alk. glucose/O2 fuel cell with a MWCNT/phthalocyanin cobalt(II) (CoPc) electrode for the oxygen redn. reaction. This nonenzymic mol. catalysis-based glucose fuel cell exhibits a power d. of Pmax = 0.182 mW cm-2 at 0.22 V and an open circuit voltage (OCV) of 0.64 V. [on SciFinder(R)]