Nanoporous silver for electrocatalysis application in alkaline fuel cells

Self-supporting porous silver foils with an average pore size < 100 nm were produced from a crystalline silver-based ternary alloy as a precursor by removing second phases present in the silver matrix. The final Ag-based porous foil shows good mechanical properties when comparing to its previous amorphous analogues. Its activity for direct electrochemical oxidation of ammonia-borane (AB), a fuel of interest for direct liquid fuel cells, has been investigated in alkaline media. The material exhibits promising electrochemical properties in long-term operation; indeed, material composition and nanostructure remain similar after 15,000 cyclic-voltammetries between − 0.3 and 0.5 V vs. RHE in a 0.1 M NaOH + 5 mM AB solution thermostated at 25 °C. Nanoporous materials, and in particular nanoporous silver, can therefore represent a relevant choice as anode in direct ammonia-borane fuel cell.