Oxygen evolution in alkali with gas diffusion electrodes

摘要

Progresses in the area of the oxygen evolution reaction (OER) are now occurring at a much faster rate relative to few years ago. For this reason, it has been deemed appropriate to present a critical review of the major and most recent contributions towards a fundamental understanding of what determines the OER electrocatalytic properties of a material. Furthermore, the technologies used to produce practical OER electrodes with top activities are assessed and the current benchmarks of performance are identified. Furthermore, results pertaining to our work on Raney-Ni gas diffusion anodes, which have been optimized in thickness and composition, are presented. An addition of 10 wt.% of a Co_3O_4 micrometric powder as co-catalyst (with Raney Ni-Fe) was found to enhance the polarization behavior and performance. The electrode so obtained achieves activities comparable with those of the best electrodes reported in the literature. Great emphasis has been placed in the analysis of the stability of the prepared Gas Diffusion Electrodes. Most of the GDEs were found to be stable in weeks long experiments with intermittent operation. The issue of integrating several functional layers (gas diffusion layer, active layer with current collector, separator layer) within a single, mechanically strong electrode assembly is briefly addressed.