Thesis (Ph.D.)-Cairo University - Faculty of Science - Department of Chemistry

Bibliography: p. 222-227.

The continuous depletion of non-renewable energy resources and their resulting harmful emissions; particularly those of traditional combustions of fossil fuels, have attracted the attention of the global community to sustain clean, affordable and efficient energy alternatives. The recent revolution of nanoscience has motivated research in liquid fuel cells by suggesting novel nanostructured materials for the catalysis of the involved anodic and cathodic reactions. Herein, a group of novel peerless inexpensive propitious binary (FeOOH/Pt) and ternary (FeOOH/NiOx/Pt and FeOOH/CoOx/Pt) anodic nanostructured catalysts has been recommended for formic acid electro-oxidation (FAO), the principal anodic reaction in the direct formic acid fuel cells (DFAFCs). In the catalysts’ preparation via the electrochemical ”layer-by-layer” methodology, a precise engineering of spherical Pt nanoparticles (nano-Pt: ca. 100 nm in average diameter) was accomplished with intersected ferric oxyhydroxide nanotubes (nano-FeOOH: ca 20 nm in average diameter) that were crystallized principally in the -FeOOH (goethite) phase. Next, a further amendment of the FeOOH@Pt catalyst with nano-NiOx (aggregated nanoparticles ca. 56 nm) and nano-CoOx (aggregated nanorods ca. 58 nm in diameter) was achieved. The FeOOH@Pt catalyst showed a significant enhancement for FAO and a potential tendency to prevent the persistent CO poisoning of the Pt substrates that endures the inherent impairment of the catalytic performance of DFAFCs. This was synchronized (relatively to nano-Pt) with a four-fold increase in the catalytic efficiency, a ca. 172 mV shift in the open circuit potential and a much (eightfold) better catalyst’s durability for FAO. The incorporation of nano-NiOx and nano-CoOx to the catalytic ingredients has incredibly boosted the catalytic efficiency toward FAO up to ca. 12-fold and 6-fold and durability up to 4-fold and 21-fold, respectively; foreseeing a quick industrialization for DFAFCs