The "catalyst" may be several elements that operate to block, bind, impede, or remove the many impurities that necessitate thorough repeated cleaning to allow the initial reaction to happen -- likely the reaction itself produces harmful impurities, so that the "catalysts" are needed to allow the reaction to continue.
If this is so, then it should be fairly obvious how to proceed to identify various impurities and test antidotes that plausibly might treat them. I suspect the stakes are so high for world security and progress that a clandestine operation will seize a working reactor and reverse engineer it. Logically, all facets of the Rossi network may have been under intensive surveillance for years, including moles. The reaction may well be straightforward new physics, just like fission in 1939, in which case it will apply to many elements and setups, and inevitably found and elucidated by the inevitable exponential expansion of science and technology. I suggest looking into the enormous body of research on metal hydrides, formed in diamond anvil ultrapressure tabletop experiments, up to the million bar level, the pressures at the center of Earth. Anomalous elements and heat may already have been found, but simply not cognized properly, in many experiments. Geology of minerals from the depths may also offer much of interest, as well as studies on minerals and melting from the early solar system. Laser implosion facilities should test tiny Ni balls full of H... Even small chemical explosion implosion experiments... Another avenue would be high current Z-pinch high current and voltage spark tests on tiny Ni tubes full of H, and then also combined with implosion from cylindrical symmetry chemical explosions. The facts about a possible new generation of simple, cheap nuclear weapons have to be kept in full view of all world citizens.
