Using a new 'megalibrary' approach to materials testing, researchers evaluated 156 million different combinations of ruthenium, cobalt, manganese, and chromium, and found one (Ru52Co33Mn9Cr6 oxide) that performs as well as or better than iridium at splitting hydrogen from water, at one-sixteenth the cost.
Original paper (not open access): https://pubs.acs.org/doi/10.1021/jacs.5c08326