Mesoporous Metal Sponges Produced by Explosive Decomposition
MB Cortie and S Supansomboon and A Dowd and MD Arnold, CHEMPHYSCHEM, 25 (2024).
DOI: 10.1002/cphc.202400439
The formation of mesoporous gold sponges by explosive decomposition of
'knallgold' (also known as 'fulminating' gold) is studied. Proof-of-
principle experiments are conducted and then the phenomena are further
investigated using 'toy physics' molecular dynamics simulations. The
simulations invoked various ratios of a volatile Lennard-Jones element G
and a noble metal element N. In both experiment and simulation the
morphology of the resulting sponge is found to depend on the
stoichiometry of the starting material. As the mole fraction of G
(chi(G)) is increased from 0.5 to close to 1.0 in the simulations, the
morphology of the sponges changes from closed to open, with a
corresponding increase in the average mean curvature from 0 to +0.12
inverse Lennard-Jones length (L) units. The average Gaussian curvature
of the simulated sponges is always negative, with the minimum value of
0.05 L-2 being found for chi(G)approximate to 0.65. In broad agreement
with experiment, sponge formation in the simulations is bounded by
stoichiometry; no sponges form if chi(G) is <0.52, for chi(G) between
0.52 and 0.70 the sponge is characterized by vermicular cavities whereas
classic bicontinuous fibrous sponges form for 0.70
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