Novel Descriptor-Driven\nDesign of Molten Alloys for\nMethane Pyrolysis

Clean hydrogen production via methane\npyrolysis using molten metal\nalloy catalysts is an interesting approach. However, the high temperatures\nand dynamic conditions required for pyrolysis render <i>in situ</i> observation of the molten metal system difficult. In this study,\nwe identified two descriptors (H* formation energy and solute metal\ndiffusivity) based on <i>ab initio</i> molecular dynamics\nsimulations to predict the catalytic activity of Bi-based binary alloys\n(M = Ni, Pt, Cu, Ag) in methane pyrolysis. The solute metals were\nactive sites for strong hydrogen adsorption, whereas solute metal\ndiffusivity determined the extent of its exposure on the surface of\nthe molten metal bubbles. Based on these findings, we identified two\nternary alloys (Bi–Ni–Cu and Bi–Ni–Mn)\nthat are catalytically more active than the binary Bi–Ni alloy.\nThis study promotes the theory-based screening of highly active alloy\ncatalysts for methane pyrolysis, thus contributing to the advancement\nof hydrogen society.