Arc melted Ag<inf>70</inf>Pd<inf>20</inf>Au<inf>10</inf> alloy specimens etched in concentrated nitric acid were studied using X-ray fluorescence spectroscopy, X-ray diffractometry, scanning electron microscopy and transmission electron microscopy. The response of nanoporous ternary alloy phase obtained from the etching to the catalytic H<inf>2</inf>O<inf>2</inf> decomposition reaction process has been studied at 298 K in aqueous acid and base mediums. The catalysis results obtained from the data analysis were compared with literature reports. Graphical Abstract: [Figure not available: see fulltext.] © 2023 Elsevier B.V., All rights reserved.